RentalBux vs. IRIS Elements Cashbook
Which MTD Software Is Better for UK Landlords and Sole Traders?
Overall Winner: RentalBux
RentalBux is the more complete MTD software for landlords and sole traders. It combines full Making Tax Digital compliance with comprehensive property management, automated bank feeds, AI-driven expense categorisation, joint ownership profit-splitting, invoicing, and a free plan for single-property landlords until March 2028 — all accessible directly by the landlord without needing an accountant to act as an intermediary. IRIS Elements Cashbook is a strong, HMRC-recognised cloud bookkeeping tool designed specifically for sole traders, offered free to clients of accountants who subscribe to qualifying IRIS compliance products. It is well-suited for self-employed individuals and landlords whose accountant already uses IRIS — but its accountant-gated access model, sole trader orientation, and lack of property management features make it a narrower fit for landlords managing portfolios independently.
At-a-Glance MTD Software Comparison
Key differences between RentalBux and IRIS Elements Cashbook across MTD compliance, property management, bookkeeping, pricing, and landlord-specific features.
| Feature | RentalBux | IRIS Elements Cashbook |
|---|---|---|
| Software Type | Property/Landlord Platform | Cloud Bookkeeping Tool (Sole Trader-Focused) |
| Target Users | Landlords, Sole Traders, Letting Agents | Sole Traders, Landlords (via accountant access) |
| Income Sources Supported | Sole Trader + UK Property + Foreign Property | Sole Trader (property income recorded; foreign property not confirmed in Cashbook) |
| Free MTD Software Plan | Free until March 2028 (1 property) | Free to landlord/client when accountant holds qualifying IRIS subscription |
| MTD Quarterly Updates to HMRC | Yes | Yes |
| Final Declaration | Yes | Yes |
| Bank Reconciliation | Yes | Yes |
| Automated Bank Feeds | Yes | Yes |
| Invoice Creation | Yes | Yes |
| Receipt Capture (OCR) | Yes | Yes |
| Expense Auto-Categorisation | Coming soon | Manual categorisation |
| Property Portfolio Management | Yes | No |
| Tenant Management | Yes | No |
| Joint Ownership & Profit Sharing | Yes | Manual |
| Payroll | No | No |
| HMO Unit-Level Tracking | Yes | No |
| HMRC SA105 Box Pre-Mapping | Yes | No |
| Spreadsheet Import/Export | Yes | Yes |
| Platform | Web, iOS, Android | Web, iOS, Android (via IRIS Elements Bookkeeping app) |
| GDPR Compliant | Yes | Yes |
What Is RentalBux? What Is IRIS Elements Cashbook?
What Is RentalBux?
All-in-One MTD Software for Landlords and Sole Traders
RentalBux is an all-in-one property management, accounting, and Making Tax Digital compliance platform built specifically for UK landlords, letting agents, and self-employed individuals. Designed with direct input from accountants who specialise in property and sole trader tax, RentalBux covers everything from tenancy management and rent collection to full bookkeeping with a pre-configured chart of accounts tailored to the property sector.
RentalBux is fully HMRC-recognised for Making Tax Digital for Income Tax across all three qualifying income categories: UK property income, foreign property income, and self-employment. This makes it one of the only landlord-specific MTD software platforms that can handle a landlord who also runs a sole trader business, all from a single subscription.
A major differentiator is RentalBux's pricing model: single-property landlords can use the platform completely free until March 2028, making it one of the most affordable HMRC-approved MTD software options for landlords entering the MTD regime.
What Is IRIS Elements Cashbook ?
IRIS Elements Cashbook is a cloud-based bookkeeping solution developed by IRIS Software Group — one of the UK's largest and longest-established accountancy software companies, trusted by over 12,000 accountancy practices. Cashbook is designed specifically to help sole traders and landlords with straightforward income digitise their bookkeeping and comply with Making Tax Digital for Income Tax Self Assessment (MTD ITSA).
IRIS Elements Cashbook is HMRC-recognised for MTD ITSA and supports quarterly updates and the final declaration — all submitted directly from within the product. The platform uses open banking via Yapily to deliver unlimited automated bank feeds, pulling transactions directly from the landlord or sole trader's bank account into the bookkeeping record. Cashbook features invoicing (up to 300 sales and purchase invoices per year), online payment collection via IRIS Pay and GoCardless, mileage tracking, customer and supplier management, CIS support, and receipt capture via the mobile app.
Strengths
- Free MTD software for single-property landlords until March 2028
- Handles sole trader + UK property + foreign property income in one platform
- Joint ownership with automatic profit-sharing split by ownership percentage
- Pre-built chart of accounts tailored for landlords and sole traders
- AI-powered expense auto-categorisation and OCR receipt capture
- Agent filing on behalf of landlords — ideal for accountants and letting agents
- Supports HMO properties with auto-created units
Strengths
- HMRC-recognised for MTD ITSA — quarterly updates and final declaration within product
- Free for clients of accountants with qualifying IRIS subscriptions
- Unlimited automated bank feeds via open banking (Yapily)
- Invoicing with online payments via IRIS Pay and GoCardless
- MTD submission reminder emails and quarterly update logs
- Mileage tracking
- Direct feed into IRIS Tax and Accounts Production for accountants
- Practice branding and client management via KashFlow Connect
- Backed by IRIS — one of the UK's most established accountancy software providers
Limitations
- Newer to market compared to established platforms
- No yield or LTV investment analysis tools
- No MTD for VAT support yet
- Some advanced reporting features still in development
- Limited third-party app integrations
- No offline capability
- No tax liability forecasting feature currently
Limitations
- Not available as a standalone product to landlords directly — must be provided by an accountant
- No property portfolio management, tenancy tracking, or rent collection features
- Invoice creation capped at 300 per year (sales and purchase combined)
- No AI-powered expense auto-categorisation
- No automated joint ownership profit-splitting
- Solely accountant-gated: landlords cannot self-register independently
- No dedicated property chart of accounts or landlord-specific expense categories
- Open banking consent (via Yapily) requires renewal every 90 days
- Limited suitability for landlords with multiple or complex property portfolios
- No formal accounting reports (no P&L, balance sheet, or trial balance beyond basic export)
Making Tax Digital Compliance
How RentalBux Handles MTD Compliance
RentalBux supports all three MTD qualifying income categories: sole trader income, UK property income, and foreign property income. This makes it suitable for landlords who also earn self-employment income, eliminating the need for separate software. Most accounts are pre-mapped to HMRC Self-Assessment boxes. RentalBux also supports agent filing, allowing accountants or letting agents to submit MTD returns on behalf of their landlord clients.
How IRIS Elements Cashbook Handles MTD Compliance
IRIS Elements Cashbook is fully HMRC-recognised for MTD ITSA. It supports digital record keeping of income and expenses, quarterly updates to HMRC, and the final declaration — all submitted directly within the Cashbook product. The platform includes periodic update reports, tax calculations, submission reminder emails, and submission logs, giving landlords and their accountants a clear audit trail of compliance activity.
IRIS describes Cashbook as being designed primarily for sole traders. In practice, landlords with UK property income can record their rental income and expenses and submit quarterly updates through the product. However, Cashbook does not offer property-specific features such as portfolio management, tenancy tracking, or a landlord-tailored chart of accounts. The final declaration is completed within Cashbook itself, unlike some competing bridging tools which require a separate product for year-end filing. Accountants managing multiple clients can monitor all MTD ITSA submissions from one central dashboard via KashFlow Connect.
| Feature | RentalBux | IRIS Elements Cashbook |
|---|---|---|
| HMRC Recognised (MTD ITSA) | Yes | Yes |
| MTD Quarterly Updates | Yes | Yes |
| Final Declaration | Yes | Yes |
| Digital Record Keeping | Yes | Yes |
| Digital Links Compliant | Yes | Yes |
| Sole Trader Income | Yes | Yes |
| UK Property Income | Yes | Yes |
| Foreign Property Income | Yes | Not confirmed |
| Multiple Income Streams | Yes | Yes |
| Agent Filing on Behalf | Yes | Yes |
Winner: RentalBux on coverage and independence — Both platforms cover UK property and sole trader income for MTD. RentalBux's confirmed foreign property income support and direct landlord access give it an advantage. IRIS Elements Cashbook's submission reminders and audit logs within the product are practical compliance strengths.
Property Management
RentalBux: Property Management
RentalBux provides comprehensive property portfolio management with tenant management, rent tracking, property expense allocation, and support for multiple properties. A standout feature is its joint ownership and profit-sharing capability: landlords can define ownership percentages once, and RentalBux automatically splits rental income and expenses. RentalBux also supports HMO properties, automatically creating individual units.
IRIS Elements Cashbook: No Property Management Features
IRIS Elements Cashbook does not include property portfolio management, tenant management, rent tracking, property expense allocation, or HMO-specific support. It is not a property management platform; it is a general bookkeeping and MTD compliance tool that accommodates landlords as users alongside sole traders. Landlords must record their rental income and expenses within Cashbook's standard bookkeeping interface. Joint ownership is handled manually — there is no automated profit-splitting. Users must enter only their personal share of income and expenses for jointly owned properties.
AccountingWEB community discussion has noted that IRIS Elements' property accounts functionality can require workarounds — for instance, some accountants have experienced difficulty producing separate property income accounts for clients with combined sole trader and property income within the IRIS Elements Tax environment. This is a known limitation worth confirming with your accountant before committing to the platform.
| Feature | RentalBux | IRIS Elements Cashbook |
|---|---|---|
| Property Portfolio Management | Yes | No |
| Tenant Management | Yes | No |
| Rent Tracking | Yes | No |
| Property Expense Allocation | Yes | No |
| Multiple Property Support | Yes | No |
| HMO Property Support | Yes (auto-creates units) | No |
| Joint Ownership/Profit Sharing | Yes (auto-split by %) | Manual (enter owner's share only) |
| Maintenance Tracking | No | No |
| Tenant Screening | No | No |
| Compliance Document Alerts | Yes | No |
| Arrears Tracking | No | No |
Winner: RentalBux — IRIS Elements Cashbook does not provide property management features. Landlords who need tenancy tracking, rent management, multi-property expense allocation, or HMO support must use RentalBux or manage these outside of Cashbook entirely.
Bookkeeping, Accounting & Digital Record Keeping
RentalBux: Structured Accounting
RentalBux includes a pre-built chart of accounts specifically designed for landlords and sole traders, covering rental income, mortgage interest, insurance, property repairs, professional services, utilities, and tenant deposits. All accounts are pre-mapped to HMRC Self-Assessment boxes. The platform supports cash basis accounting, bank reconciliation, and journal entries.
IRIS Elements Cashbook: Cloud Bookkeeping with Unlimited Bank Feeds
IRIS Elements Cashbook uses open banking via Yapily to deliver unlimited automated bank feeds, pulling transactions from the user's bank account directly into Cashbook. This eliminates manual data entry and ensures the bookkeeping record stays current. Cashbook uses a standard chart of accounts rather than a landlord-tailored one, and does not offer journal entries or formal accounting reports such as a profit & loss statement, balance sheet, or trial balance within the product itself. A trial balance can be exported into IRIS Accounts Production or IRIS Elements Tax, where the accountant can complete formal accounts and tax work. Note that Yapily open banking consent requires renewal every 90 days.
| Feature | RentalBux | IRIS Elements Cashbook |
|---|---|---|
| Cash Basis Accounting | Yes | Yes |
| Chart of Accounts (Pre-built, Landlord-Tailored) | Yes (pre-built + custom) | Standard (not landlord-specific) |
| Journal Entries | Yes | No |
| Bank Reconciliation | Yes | Yes |
| Automated Bank Feeds | Yes (Major UK banks) | Yes |
| Open Banking Integration | Yes | Yes |
| Double-Entry Bookkeeping | Yes | No |
| HMRC Box Pre-Mapping | Yes | No |
| Xero Integration | No | No |
| Spreadsheet Import/Export | Yes | Yes |
| Digital Record Storage | Yes | Yes |
Winner: RentalBux — The landlord-tailored chart of accounts, journal entries, double-entry bookkeeping, and structured accounting framework give RentalBux a deeper accounting foundation. IRIS Elements Cashbook's unlimited bank feeds are a genuine strength for day-to-day digital record keeping, but it relies on the accountant and IRIS Tax products to complete formal year-end accounts.
Invoicing, Expense Tracking
RentalBux: Expense Management
RentalBux includes OCR receipt capture, structured expense tracking with landlord-specific categories, auto-categorisation, invoice creation with customisable branding, and payment tracking with reminders.
IRIS Elements Cashbook: Capped Invoicing with IRIS Pay
IRIS Elements Cashbook supports creating and sending sales and purchase invoices — up to 300 of each per year — with invoice customisation including a logo. Clients can receive payments directly via IRIS Pay (IRIS's integrated payment solution) or GoCardless for direct debit. Customer statements can be scheduled. Mileage tracking is available. Receipt capture is available via the IRIS Elements Bookkeeping mobile app. However, there is no AI-powered auto-categorisation of expenses; users categorise transactions manually after bank feeds pull them in.
The 300-invoice annual cap is worth noting. For landlords with a small number of properties issuing a handful of rent invoices each month, this is unlikely to be a constraint. For commercial landlords or those with large numbers of tenants issuing invoices monthly, the cap may be a limiting factor.
| Feature | RentalBux | IRIS Elements Cashbook |
|---|---|---|
| Invoice Creation & Sending | Yes | Yes |
| Invoice Customisation/Branding | Yes | Yes |
| Online Payment Collection | Yes | Yes |
| Payment Tracking/Reminders | Yes | Yes |
| Expense Tracking | Yes | Yes |
| Receipt Capture (OCR/Photo) | Yes | Yes |
| Expense Categorisation | Yes | Yes |
| Automated Transaction Matching | Yes | Yes |
| Mileage Tracking | No | Yes |
| AI Auto-Categorisation | Coming soon | No |
Winner: Tie — RentalBux wins on AI auto-categorisation and invoice volume. IRIS Elements Cashbook wins on mileage tracking and the IRIS Pay / GoCardless payment integration. For most residential landlords, both provide adequate invoicing capability within the annual cap.
Reporting & Tax Forecasting
RentalBux: Formal Accounting Reports
RentalBux produces structured financial reports including profit & loss statements, balance sheets, journal reports, ledger reports, and trial balances. Smart categorisation helps ensure accuracy.
IRIS Elements Cashbook: Bookkeeping Dashboard with Accountant-Side Reporting
IRIS Elements Cashbook provides clients with a live dashboard showing current financial status based on bank feed data. Formal accounting reports are not generated within Cashbook itself. Instead, the trial balance is exported to IRIS Accounts Production or IRIS Elements Tax, where the accountant produces the formal accounts. IRIS's broader suite — including the IRIS Accountancy Suite — provides comprehensive reporting capabilities for practices, but this sits outside the Cashbook product itself.
| Feature | RentalBux | IRIS Elements Cashbook |
|---|---|---|
| Profit & Loss Report | Yes (formal) | No (trial balance export to accountant only) |
| Balance Sheet | Yes | No |
| Trial Balance | Yes | Yes |
| Dashboard/Overview | Yes | Yes |
| Real-Time Financial Data | Yes | Yes |
| Cash Flow Reporting | No | Partial |
| Tax Estimate/Forecast | Yes | No |
| AI-Powered Features | Coming soon | No |
Winner: RentalBux — RentalBux produces formal P&L, balance sheet, and trial balance reports within the platform. IRIS Elements Cashbook relies on the accountant to generate these using IRIS Tax or Accounts Production products. For landlords who want direct access to their own financial reports, RentalBux is the stronger choice.
Collaboration & Mobile Apps
RentalBux's Collaborative Features
RentalBux enables agent filing, which gives accountants and letting agents the ability to submit directly on a landlord's behalf.
IRIS Elements Cashbook: Accountant-Controlled Client Access
The collaboration model for IRIS Elements Cashbook is uniquely accountant-centric. The accountant uses their free KashFlow Connect account to create accounts for sole trader clients, control which features are visible, apply practice branding, and publish bulk announcements to all clients' dashboards. The accountant can submit MTD returns on behalf of clients (agent filing) directly from KashFlow Connect. Clients access their own data but within the accountant-configured environment. This is a well-designed workflow for IRIS accountancy practices that want to centralise client bookkeeping within their existing IRIS ecosystem --- but it means clients are entirely dependent on their accountant's subscription remaining active and eligible.
| Feature | RentalBux | IRIS Elements Cashbook |
|---|---|---|
| Accountant/Advisor Portal | Yes | Yes |
| Multi-User Access | Yes | Yes |
| Agent Filing on Behalf | Yes | Yes |
| Bank Integration | Yes | Yes |
| Platform | iOS, Android | iOS, Android |
| Web Browser Access | Yes | Yes |
| FCA Regulated | Yes | No |
| GDPR Compliant | Yes | Yes |
Winner: Depends on use case — RentalBux wins for landlords who want independent self-serve access and agent support. IRIS Elements Cashbook wins for accountants managing large numbers of sole trader and landlord clients within the IRIS ecosystem, with the practice management and branding capabilities of KashFlow Connect.
Ease of Use, Support & Security
RentalBux: Guided Workflows
RentalBux uses guided workflows, clear dashboards, and no accounting jargon. The platform offers phone support, email/chat support, and a help centre with guides and knowledge base articles.
IRIS Elements Cashbook: Ease of Use
IRIS Elements Cashbook is described by IRIS as an easy, step-by-step tool to help sole traders start the digital journey. It is accessed via a web browser or the IRIS Elements Bookkeeping mobile app (available on Android, iOS, and Chromebook). IRIS Software Group is one of the UK's largest and most established accountancy software providers, with an HMRC acceptance rate of over 98% cited across its product suite. Phone support is available on 0344 815 5555. However, AccountingWEB community discussions have noted that support responsiveness for some IRIS Elements products can be variable, and that certain property accounting workflows within the IRIS Elements ecosystem require workarounds. As a cloud product, Cashbook can be accessed anytime, anywhere, from any internet-connected device.
| Feature | RentalBux | IRIS Elements Cashbook |
|---|---|---|
| Phone Support | Yes | Yes |
| Chat Support | Yes | No |
| Email Support | Yes | Yes |
| Help Centre/Knowledge Base | Yes | Yes |
| FCA Regulated | Yes | No |
| Enterprise-Grade Security | Yes | Yes |
RentalBux Features
Sole Trader Income Support for MTD
RentalBux is one of the few landlord-focused MTD software platforms that supports self-employment income alongside UK and foreign property income within a single account. Landlords who also run a trade, consultancy, or freelance business can manage all quarterly submissions from one dashboard. Landlord Studio covers property income only.
Custom Chart of Accounts for Landlords
A property-tailored chart of accounts covering rental income, mortgage interest, insurance, repairs, utilities, letting agent fees, and more — all pre-mapped to HMRC Self-Assessment boxes. No setup required; the system is ready to use from day one. Landlord Studio has no equivalent.
Agent Filing on Behalf of Landlords
Letting agents and accountants can submit MTD quarterly updates and the Final Declaration on behalf of landlord clients directly from the platform. Landlord Studio allows accountant access but does not support submission on the landlord's behalf.
Branded Invoice Creation
Invoice creation with customisable branding for service charges and commercial landlords. Not available in Landlord Studio.
AI-Powered OCR Receipt Capture with Auto-Categorisation (Coming soon)
RentalBux's AI will read uploaded receipts and categorise the expense automatically against the pre-built chart of accounts. Landlord Studio's Smart Scan extracts dates and amounts but does not include AI-driven expense categorisation.
Formal Accounting Reports
Balance sheet, trial balance, ledger reports, and journal reports. Landlord Studio does not produce these natively.
Free Plan Including MTD Submissions Until March 2028
RentalBux's free single-property plan includes MTD quarterly submissions. Landlord Studio's free GO plan covers property management for up to three units but requires a paid PRO plan (from £12/month) to access MTD submission functionality.
Unique Features Only IRIS Elements Cashbook Offers
Accountant-Managed Client Experience via KashFlow Connect
Accountants using IRIS can give clients access to a practice-branded version of Cashbook, control which features they see, and send bulk announcements to all clients from one dashboard.
Seamless Integration with IRIS Tax and Accounts Production
Trial balances export directly from Cashbook into IRIS Elements Tax, IRIS Accountancy Suite Personal Tax, Business Tax, and Accounts Production — making year-end work faster for IRIS-based practices without any manual rekeying.
Mileage Tracking
IRIS Elements Cashbook includes built-in mileage recording, which is useful for sole traders and landlords who travel to and from properties and wish to claim mileage as an allowable expense.
IRIS Pay and GoCardless Payment Integration
IRIS Pay is IRIS's market-leading invoice payment solution, allowing clients to request and receive payments on the go via mobile. GoCardless direct debit integration is also available. Together these offer a flexible payment collection toolkit within the bookkeeping product.
Unlimited Bank Feeds
IRIS Elements Cashbook provides unlimited bank feeds via Yapily open banking, with no restriction on the number of bank accounts connected. This is particularly useful for landlords with transactions spread across multiple accounts.
Practice Branding
Accountants can apply their own branding to the client-facing Cashbook interface, presenting a professionally consistent experience that reinforces the accountant-client relationship.
Who Should Choose RentalBux?
RentalBux is a strong fit if you:
Landlords with Mixed Income Streams
If you earn from both property and self-employment, RentalBux handles sole trader income alongside UK and foreign property income in a single MTD-compliant platform.
Joint Owners and Family Portfolios
The automated profit-sharing split is a standout feature. Define ownership percentages once and RentalBux calculates each owner's share automatically.
Budget-Conscious Landlords Entering MTD
Free MTD software for single-property landlords until March 2028, with no upfront commitment.
Landlords Who Want Proper Accounting Structure
Chart of accounts, journal entries, profit & loss, balance sheet, and trial balance give RentalBux a structured accounting foundation.
Accountants and Letting Agents
Agent filing on behalf, multi-user access, and spreadsheet import make RentalBux practical for professionals managing multiple landlord portfolios.
Commercial Landlords and HMO Owners
Invoice creation with branding for service charges, plus automatic HMO unit creation and tenant management.
Who should choose IRIS Elements Cashbook?
IRIS Elements Cashbook is the better choice for:
Landlords Whose Accountant Already Uses IRIS
f your accountant subscribes to IRIS Personal Tax, IRIS Business Tax, IRIS Elements Tax, or other qualifying IRIS products, Cashbook is available to you at no additional cost, with a seamless end-to-end workflow from bookkeeping through to tax filing.
Sole Traders with Simple Property Income as a Secondary Income
Cashbook is designed first and foremost for sole traders. Landlords who also have self-employment income, and whose property portfolio is relatively simple, will find it a clean and capable MTD bookkeeping tool.
Landlords Who Want Automated Bank Feeds Without Migration Complexity
Cashbook's unlimited open banking feeds via Yapily make it easy to start capturing transactions digitally with minimal setup — ideal for landlords moving away from spreadsheets or manual records.
Landlords Who Want In-Product Payment Collection
IRIS Pay and GoCardless integration within Cashbook make it easy to send invoices and collect rent or service charge payments directly, without needing a separate payment tool.
Accountants Building an IRIS-First Client Workflow
For practices wanting a branded, tightly integrated bookkeeping-to-tax pipeline using IRIS products exclusively, Cashbook is a natural, free addition to the accountant's toolkit — with KashFlow Connect providing full practice-side management.