RentalBux vs. 123 Sheets Accounting Software
Which MTD Software Is Better for UK Landlords and Sole Traders?
Overall Winner: RentalBux
RentalBux is the more complete MTD solution for landlords and sole traders. It combines full Making Tax Digital compliance across UK property income, foreign property income, and self-employment income with comprehensive property management, automated bookkeeping, AI-driven expense categorisation, joint ownership profit-splitting, and a free plan for single-property landlords until March 2028. 123 Sheets is a strong alternative for landlords and sole traders who already use Excel or another spreadsheet application and want one of the most affordable, user-friendly, and well-reviewed bridging tools on the market. However, its focus on spreadsheet submission — with no bookkeeping, property management, bank feeds, or reporting features — makes it a compliance tool rather than a management platform, and landlords must maintain their own HMRC-compliant digital records independently.
At-a-Glance MTD Software Comparison
Key differences between RentalBux and 123 Sheets across MTD compliance, property management, bookkeeping, pricing, and landlord-specific features.
| Feature | RentalBux | 123 Sheets |
|---|---|---|
| Software Type | Property/Landlord Platform | Web-Based Bridging Software |
| Target Users | Landlords, Sole Traders, Letting Agents | Landlords, Sole Traders, Accountants |
| Income Sources Supported | Sole Trader + UK Property + Foreign Property | Sole Trader + UK Property |
| Free MTD Software Plan | Free until March 2028 (1 property) | No |
| MTD Quarterly Updates to HMRC | Yes | Yes |
| Final Declaration | Yes | Yes |
| Bank Reconciliation | Yes | No |
| Automated Bank Feeds | Yes | No |
| Invoice Creation | Yes | No |
| Receipt Capture (OCR) | Yes | No |
| Expense Auto-Categorisation | Coming soon | No |
| Property Portfolio Management | Yes | No |
| Tenant Management | Yes | No |
| Joint Ownership & Profit Sharing | Yes | No |
| Payroll | No | No |
| HMO Unit-Level Tracking | Yes | No |
| HMRC SA105 Box Pre-Mapping | Yes | Yes |
| Spreadsheet Import/Export | Yes | Yes |
| Platform | Web, iOS, Android | Web browser only |
| GDPR Compliant | Yes | No |
What Is RentalBux? What Is 123 Sheets Accounting Software?
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 123 Sheets?
The Making Tax Digital Spreadsheet Specialists
123 Sheets is a web-based Making Tax Digital bridging platform founded by accountant Peter Hamilton specifically to help spreadsheet users meet HMRC's digital submission requirements without abandoning their existing workflows. It is one of the most established and highly reviewed bridging tools in the UK market, having already processed submissions for over 35,000 VAT businesses and earning a five-star average from more than 1,900 Trustpilot reviews. The platform holds ISO 27001 and Cyber Essentials Plus security certifications and is HMRC-recognised for both MTD for VAT and MTD for Income Tax (ITSA).
123 Sheets takes a guided approach to bridging. Rather than requiring users to map their own spreadsheet cells to HMRC fields — as some competitors do — it provides pre-formatted Excel, Google Sheets, LibreOffice, and Apple Numbers templates with income and expense categories already matched to HMRC's required categories. Users enter their data into the template and upload it to the 123 Sheets website for submission. Alternatively, users of Sage, QuickBooks, or other accounting packages can export their profit and loss report to Excel and upload that file directly, meaning 123 Sheets is compatible with virtually any existing bookkeeping system.
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 VAT and MTD ITSA
- Excellent Trustpilot rating — 5 stars from 1,900+ reviews
- Pre-formatted landlord and sole trader spreadsheet templates
- Web-based — works on any browser, any device, any OS
- Compatible with Excel, Google Sheets, Sage, QuickBooks, LibreOffice, Numbers
- Per-taxpayer licence covers all income sources (sole trader + property)
- ISO 27001 and Cyber Essentials Plus certified
- Very low annual cost — £19.75 + VAT per taxpayer
- Accountant portal with To Do and Deadline tracking
- Demo available free before purchasing
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
- Bridging only — does not create or maintain digital records
- No property management, tenant management, or rent tracking
- No bank feeds or automated transaction matching
- No AI categorisation, OCR receipt capture, or invoice creation
- No formal accounting reports (P&L, balance sheet, trial balance)
- No phone support — email and online only
- No free plan for live submissions (demo only)
- Interface described as functional but dated by some reviewers
- Foreign property income support not confirmed for ITSA
- No mobile app — browser-based only
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 123 Sheets Handles MTD Compliance
123 Sheets is HMRC-recognised for MTD for Income Tax, supporting sole trader income and UK property income for quarterly updates and final declarations. The platform provides pre-formatted spreadsheet templates with HMRC income and expense categories already matched, eliminating the need for users to configure their own cell mappings. Users upload their completed spreadsheet to the 123 Sheets website, where it is validated and transmitted to HMRC. Critically, 123 Sheets does not create or maintain the underlying digital records — that responsibility remains with the user in their spreadsheet. The per-taxpayer licensing model means a single licence covers a client with both self-employment and property income, with all their required submissions appearing on a single To Do dashboard.
| Feature | RentalBux | 123 Sheets |
|---|---|---|
| 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 | No |
| Multiple Income Streams | Yes | Yes |
| Agent Filing on Behalf | Yes | Yes |
Winner: RentalBux — Both platforms cover sole trader and UK property income, but RentalBux creates and maintains compliant digital records automatically and also covers foreign property income. 123 Sheets has an advantage on MTD for VAT, but for ITSA, RentalBux provides a more complete end-to-end compliance solution.
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.
123 Sheets: No Property Management Features
123 Sheets has no property management functionality. It does not track tenancies, manage rent, record compliance deadlines, allocate expenses to individual properties, or provide any landlord-specific workflows beyond its pre-formatted income and expense templates. All property administration must be managed in separate software or spreadsheets. For landlords who simply need a tool to submit their existing spreadsheet records to HMRC, this is a deliberate design choice that keeps the platform simple and affordable.
| Feature | RentalBux | 123 Sheets |
|---|---|---|
| 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 %) | No |
| Maintenance Tracking | No | No |
| Tenant Screening | No | No |
| Compliance Document Alerts | Yes | No |
| Arrears Tracking | No | No |
Winner: RentalBux — 123 Sheets has no property management features. RentalBux provides a full landlord management suite including tenancy management, rent tracking, HMO support, joint ownership profit-splitting, and compliance alerts. The only landlord-specific provision from 123 Sheets is its pre-formatted landlord income template.
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.
123 Sheets: Structured Templates, No Bookkeeping Engine
123 Sheets does not perform bookkeeping functions in the traditional sense, but it does provide a meaningful layer of structure for spreadsheet users through its pre-formatted templates. These templates have income and expense categories already matched to HMRC's required categories, include ledger-style reports, handle disallowable expenditure, and produce profit reports per self-employment unit for those with multiple business activities. Users of Sage, QuickBooks, and other accounting software can export their profit and loss report to Excel and upload it directly, without needing to re-enter data. However, 123 Sheets does not provide bank feeds, journal entries, a chart of accounts, or automated reconciliation.
| Feature | RentalBux | 123 Sheets |
|---|---|---|
| Cash Basis Accounting | Yes | Yes |
| Chart of Accounts (Pre-built, Landlord-Tailored) | Yes (pre-built + custom) | No |
| Journal Entries | Yes | No |
| Bank Reconciliation | Yes | No |
| Automated Bank Feeds | Yes (Major UK banks) | No |
| Open Banking Integration | Yes | No |
| Double-Entry Bookkeeping | Yes | No |
| HMRC Box Pre-Mapping | Yes | Yes |
| Xero Integration | No | No |
| Spreadsheet Import/Export | Yes | Yes |
| Digital Record Storage | Yes | No |
Winner: RentalBux — RentalBux provides a complete bookkeeping engine with chart of accounts, journals, bank feeds, and automated reconciliation. 123 Sheets Accounting Software provides well-structured templates that are genuinely useful, but does not replace bookkeeping software for landlords with complex records.
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.
123 Sheets: No Expense Tracking or Invoicing Features
123 Sheets takes no active role in expense management. As a bridging submission tool, it does not record, categorise, or process any individual expense data — that work is entirely the responsibility of the user in their spreadsheet, prior to uploading. There are no automation features, no receipt scanning, and no invoice creation capabilities. The pre-formatted templates do provide HMRC-matched expense categories as a structural guide, which helps users ensure their records are organised correctly before submission — but the data entry itself is entirely manual.
| Feature | RentalBux | 123 Sheets |
|---|---|---|
| Invoice Creation & Sending | Yes | No |
| Invoice Customisation/Branding | Yes | No |
| Online Payment Collection | Yes | No |
| Payment Tracking/Reminders | Yes | No |
| Expense Tracking | Yes | No |
| Receipt Capture (OCR/Photo) | Yes | No |
| Expense Categorisation | Yes | Partial |
| Automated Transaction Matching | Yes | No |
| Mileage Tracking | No | No |
| AI Auto-Categorisation | Coming soon | No |
Winner: RentalBux — 123 Sheets' HMRC-matched template categories are a useful structural guide but do not replace active expense tracking. RentalBux's OCR, automatic expense categorisation, and branded invoicing give it a decisive advantage for landlords who want to maximise allowable deductions.
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.
123 Sheets: Template-Level Reporting, No Formal Accounting Reports
123 Sheets does not produce formal standalone accounting reports from within the platform. However, its own spreadsheet templates do include ledger reports, profit summaries per self-employment unit, and disallowable expenditure handling — providing a level of financial visibility that goes beyond a basic submission form. For landlords who already use Sage or QuickBooks, the underlying software will continue to generate their full financial reports; 123 Sheets simply handles the HMRC transmission layer. The platform does not produce tax estimates, portfolio dashboards, or investment analysis of any kind.
| Feature | RentalBux | 123 Sheets |
|---|---|---|
| Profit & Loss Report | Yes (formal) | Partial |
| Balance Sheet | Yes | No |
| Trial Balance | Yes | No |
| Dashboard/Overview | Yes | Yes |
| Real-Time Financial Data | Yes | No |
| Cash Flow Reporting | No | No |
| Tax Estimate/Forecast | Yes | No |
| AI-Powered Features | Coming soon | No |
Winner: RentalBux — RentalBux leads on all formal accounting reports. 123 Sheets Accounting Software provides useful template-level summaries but does not produce standalone accounting reports from within the platform itself.
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.
123 Sheets: Accountant-First Design with Per-Taxpayer Licensing
123 Sheets was designed with accountants in mind from the outset, and its agent features reflect that priority. The dedicated agent login provides access to a To Do page listing all client submissions ordered by due date, a Deadline tracking system, and historic submission records — all without requiring the landlord to log in or action anything themselves. The per-taxpayer licensing model is a significant practical advantage for accountancy practices: a single licence covers all of a client's income sources, whether self-employed, a landlord, or both, avoiding the per-business charges that some competitors apply. The platform is web-based, meaning it works on any device with a browser — though there is no dedicated mobile app.
| Feature | RentalBux | 123 Sheets |
|---|---|---|
| Accountant/Advisor Portal | Yes | Yes |
| Multi-User Access | Yes | Yes |
| Agent Filing on Behalf | Yes | Yes |
| Bank Integration | Yes | Yes |
| Platform | iOS, Android | Web browser only |
| Web Browser Access | Yes | Yes |
| FCA Regulated | Yes | No |
| GDPR Compliant | Yes | No |
Winner: Tie — depends on priorities. RentalBux wins on mobile access, bank integration, and enabling landlord self-management. 123 Sheets wins on per-taxpayer licensing value and its purpose-built accountant workflow tools. Accountants managing many clients with mixed income sources may prefer 123 Sheets' pricing structure.
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.
123 Sheets: Simple Web Interface with Strong Security Credentials
123 Sheets is consistently praised by users for its simplicity and speed. The three-step submission workflow — enter data in the template, upload the spreadsheet, submit to HMRC — is described by many reviewers as taking only a few minutes per quarter. The web-based interface requires no installation, works on any device with a browser, and has been refined over years of VAT submissions. Some reviewers note the interface looks functional rather than modern, but the overwhelming consensus across 1,900+ Trustpilot reviews is that it does exactly what it promises with minimal friction. Customer support is available via email and online, but there is no phone support. On the security side, 123 Sheets holds ISO 27001 and Cyber Essentials Plus certifications alongside GDPR compliance — security credentials that exceed those of many competing bridging tools.
| Feature | RentalBux | 123 Sheets |
|---|---|---|
| Phone Support | Yes | No |
| Chat Support | Yes | Yes |
| Email Support | Yes | Yes |
| Help Centre/Knowledge Base | Yes | Yes |
| FCA Regulated | Yes | No |
| Enterprise-Grade Security | Yes | No |
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 123 Sheets Offers
Per-taxpayer licensing for accountants
A single licence covers all income sources for one client (sole trader + property), regardless of how many businesses or properties they have. Competitors often charge per business entity, making 123 Sheets significantly more cost-effective for practices managing mixed-income clients.
Pre-formatted HMRC-matched templates for multiple platforms
Ready-to-use spreadsheet templates for Excel (1997+ and 2010+), Google Sheets, Apple Numbers, LibreOffice, and OpenOffice — covering both landlord and sole trader income. Users can adopt the 123 Sheets template or link their own existing spreadsheet.
MTD for VAT — established and proven
123 Sheets has been submitting VAT returns for over 35,000 businesses since MTD for VAT launched.
Sage and QuickBooks compatibility
Users of Sage 50, QuickBooks, and similar accounting software can export their profit and loss report to Excel and upload it directly to 123 Sheets, preserving existing workflows.
ISO 27001 and Cyber Essentials Plus certification
123 Sheets holds independently verified security certifications that go beyond standard GDPR compliance — relevant for accountancy practices with data security obligations.
Accountant-oriented To Do and Deadline dashboard
A dedicated agent view listing all clients' outstanding submissions ordered by due date, with historic records — purpose-built for practices managing multiple MTD clients efficiently.
Free demo before purchasing
Prospective users can try a full single-taxpayer demo before committing to a paid licence, reducing purchasing risk.
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 123 Sheets?
123 Sheets is the better choice for:
Landlords and sole traders who already use spreadsheets.
If your records are well-organised in Excel, Google Sheets, LibreOffice, or a similar application, 123 Sheets provides the cheapest and simplest path to MTD compliance without rebuilding your workflow.
Existing Sage or QuickBooks users
Export your profit and loss report from your accounting software to Excel, upload it to 123 Sheets, and submit — no additional data entry, no software migration.
Accountants managing large volumes of mixed-income clients
The per-taxpayer licence covers all income sources for each client under one National Insurance number. This is significantly more cost-effective than per-business pricing models for practices with many mixed-income clients.
VAT-registered landlords and sole traders
123 Sheets has a well-proven MTD for VAT offering used by 35,000+ businesses. If you already use it for VAT, staying with the same platform for ITSA reduces complexity and cost.
Users who prioritise independently verified security
ISO 27001 and Cyber Essentials Plus certifications are particularly relevant for accountancy practices with data protection obligations.
Landlords seeking a low-cost interim or permanent compliance solution
At £19.75 + VAT per year (with introductory discounts available), 123 Sheets is one of the most affordable HMRC-recognised MTD options available for any landlord or sole trader.