RentalBux vs. Capium
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 seeking a direct-access, standalone platform. 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. Capium is a powerful, award-winning, cloud-based accountancy suite designed for UK accounting practices — not individual landlords. Its MTD offering is practice-first: delivered through accountants who use the Capium platform to manage their landlord and sole trader clients' MTD compliance at scale, with Capium 365 (priced at £11.99/month per client) providing the client-facing bookkeeping and record-keeping component. For landlords who want direct, self-serve access to property management and MTD compliance without accountant intermediation, RentalBux is the clear choice. For accountancy practices managing multiple landlord clients who want a fully integrated, modular cloud suite with MTD IT, Self Assessment, Accounts Production, Corporation Tax, Payroll, and AML in one platform, Capium is one of the most comprehensive practice tools available.
At-a-Glance MTD Software Comparison
Key differences between RentalBux and Capium across MTD compliance, property management, bookkeeping, pricing, and landlord-specific features.
| Feature | RentalBux | Capium |
|---|---|---|
| Software Type | Property/Landlord Platform | Accountancy Practice Management Suite + Client Bookkeeping Tool |
| Target Users | Landlords, Sole Traders, Letting Agents | Accountancy Practices; Landlord/Sole Trader Clients via Accountants |
| Income Sources Supported | Sole Trader + UK Property + Foreign Property | Self-Employment + UK Property + Foreign Property (Capium 365 supports income stream categorisation) |
| Free MTD Software Plan | Free until March 2028 (1 property) | No free plan; Capium 365 is £11.99/month per client (£7.99 introductory for existing Capium customers) |
| 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 | Yes |
| Property Portfolio Management | Yes | No |
| Tenant Management | Yes | No |
| Joint Ownership & Profit Sharing | Yes | No dedicated joint ownership feature confirmed |
| Payroll | No | Yes |
| HMO Unit-Level Tracking | Yes | No |
| HMRC SA105 Box Pre-Mapping | Yes | Partial |
| Spreadsheet Import/Export | Yes | Yes |
| Platform | Web, iOS, Android | Web, iOS, Android |
| GDPR Compliant | Yes | Yes |
What Is RentalBux? What Is Capium?
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 Capium?
Fully Integrated Accountancy Software. That Works For You
Capium is a UK-based, cloud-native accountancy practice management platform, founded in 2013, that provides a fully integrated suite of compliance and practice management tools for accountancy firms. Trusted by thousands of UK accounting practices managing over 300,000 clients, Capium is recognised by both HMRC and Companies House, and is an award-winning platform — voted Accounting Excellence Small Business Accounting Software of the Year.
Capium's product suite is modular, covering: Bookkeeping, Self Assessment, Accounts Production, Corporation Tax, Payroll, Practice Management, Company Secretarial, Anti-Money Laundering, MTD for VAT, MTD for Income Tax, Charity Accounts, Time and Fees, and — for MTD IT client record keeping — Capium 365. All modules are fully integrated so that data entered in one flows automatically through to the others.
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 MTD IT — confirmed live pilot completions for UK Property + Self-Employment
- Self-employment, UK property, and foreign income all supported via configurable income stream categorisation
- Unlimited bank feeds included free with Capium 365 licence
- Receipt upload: up to 50 invoices/receipts scanned at once via mobile or web
- Unlimited invoices, unlimited users, unlimited document storage (Capium 365)
- Full integrated practice suite: SA, AP, CT, Payroll, AML, CoSec, VAT, MTD IT in one platform
- Bulk document requests — accountant can chase multiple clients for receipts at once
- Client portal for document sharing and collaboration
- Automated transaction categorisation with supplier rules
- Multi-platform access: mobile, tablet, desktop
- 6-day-a-week support and free onboarding included
- Voted Accounting Excellence Small Business Accounting Software of the Year
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 a direct-to-landlord tool — landlords can only access Capium 365 through an accountant
- No property portfolio management, tenancy tracking, or rent collection
- No joint ownership auto-splitting feature confirmed
- Capium 365 is £11.99/month per client — cost sits with the practice (passed on to client)
- Some modules noted as less polished than others in user reviews
- Modular pricing can be expensive for full-suite practices
- No direct free plan for individual landlords
- No landlord-specific chart of accounts or property expense categories
- Third-party integrations more limited than some competitors
- No API available
- Property management entirely outside the platform's scope
- Individual landlords cannot self-register for Capium 365 directly
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 Capium Handles MTD Compliance
Capium's MTD for Income Tax solution operates at two levels. At the practice level, accountants use Capium's MTD module and practice management suite to manage all client MTD quarterly submissions, track deadlines, review submission status, and handle final declarations. At the client level, Capium 365 provides the bookkeeping and record-keeping interface through which landlords and sole traders capture receipts, connect bank feeds, and categorise income and expenses.
Capium's official MTD IT page explicitly states that self-employment, UK property, and foreign income reports are automatically populated from live digital records for MTD quarterly updates and final declarations. AccountingWEB confirmed that Capium 365 allows accountants to configure income stream categorisation so clients can clearly distinguish between UK and foreign sources, or between property and self-employment income. Capium has confirmed live pilot completions for both UK Property income and Self-Employment tax returns through the HMRC MTD pilot.
| Feature | RentalBux | Capium |
|---|---|---|
| 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 | Yes |
| Multiple Income Streams | Yes | Yes |
| Agent Filing on Behalf | Yes | Yes |
Winner: RentalBux for direct landlord access; Capium for practice-led multi-client management — Both platforms cover all three MTD income categories. RentalBux allows landlords to submit directly without accountant involvement. Capium's MTD IT is designed for accountants managing multiple clients; it does not provide direct self-service submission for individual landlords. For practices managing large landlord client bases, Capium's structured workflow, deadline tracking, and bulk document request tools are genuine operational advantages.
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.
Capium: No Property Management Features
Capium does not include property portfolio management, tenant management, rent tracking, compliance document reminders, HMO support, or any landlord-specific property administration tools. It is an accountancy practice management platform. Property management is entirely outside Capium's scope and must be handled separately by the landlord or via other specialist tools.
| Feature | RentalBux | Capium |
|---|---|---|
| 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 | Partial |
Winner: RentalBux — by a very wide margin Capium has no landlord or property management features. This reflects its design as an accountancy practice tool rather than a landlord platform.
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.
Capium 365: Cloud Bookkeeping for Sole Traders and Landlords (Practice-Delivered)
Capium 365 is a cloud-based bookkeeping solution that provides the client-facing record keeping for MTD IT. It includes unlimited bank feeds (free with a Capium 365 licence), automated bank reconciliation, automated transaction categorisation with supplier rules, and the ability to upload up to 50 invoices and receipts at once. Income streams can be configured by the accountant to clearly separate UK property, foreign property, and self-employment income. P&L reports are available for limited company clients within Capium 365. For landlords with more complex accounting needs, all Capium 365 data feeds directly into the practice's Capium suite for self-assessment, accounts production, and year-end work.
| Feature | RentalBux | Capium |
|---|---|---|
| Cash Basis Accounting | Yes | Yes |
| Chart of Accounts (Pre-built, Landlord-Tailored) | Yes (pre-built + custom) | No |
| Journal Entries | Yes | Yes |
| Bank Reconciliation | Yes | Yes |
| Automated Bank Feeds | Yes (Major UK banks) | Yes |
| Open Banking Integration | Yes | Yes |
| Double-Entry Bookkeeping | Yes | Yes |
| HMRC Box Pre-Mapping | Yes | Partial |
| Xero Integration | No | Yes |
| Spreadsheet Import/Export | Yes | Yes |
| Digital Record Storage | Yes | Yes |
Winner: Depends on the user — RentalBux wins for landlords who want direct, self-serve accounting with a landlord-specific structure. Capium wins comprehensively for accountancy practices that need a full integrated suite covering MTD IT, VAT, SA, AP, CT, Payroll, AML, and CoSec in one platform — representing a depth of compliance tooling that no landlord-facing software can match.
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.
Capium 365: Bulk Receipt Upload with Accountant-Driven Document Requests
Capium 365 allows clients to scan and upload up to 50 invoices and receipts at once through the mobile app or web platform. Supplier rules and automation handle transaction categorisation. A distinctive feature is Capium's bulk document request tool: accountants can send batched requests to multiple clients simultaneously, asking for specific receipts or documents, and then track which clients have submitted and which have not — significantly reducing the time spent chasing clients ahead of quarterly MTD submissions.
| Feature | RentalBux | Capium |
|---|---|---|
| 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 | No |
| AI Auto-Categorisation | Coming soon | Partial |
Winner: Tie — RentalBux wins on receipt extraction. Capium 365 wins on bulk document management and accountant-side tracking — features with no equivalent in direct-to-landlord platforms.
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.
Capium: Practice-Wide Dashboards and Statutory Reporting
Capium's practice dashboard gives accountants full submission status visibility across all MTD IT clients — tracking which quarterly updates have been submitted, which are pending, and which are overdue. Capium's Accounts Production module produces full statutory accounts (full, abbreviated, or abridged year-end accounts) submitted directly to Companies House. The Self Assessment module produces all SA forms. Real-time data flows between modules so information entered once in bookkeeping or Capium 365 auto-populates into SA, CT, and AP.
| Feature | RentalBux | Capium |
|---|---|---|
| Profit & Loss Report | Yes (formal) | Yes |
| Balance Sheet | Yes | Yes |
| Trial Balance | Yes | Yes |
| Dashboard/Overview | Yes | Yes |
| Real-Time Financial Data | Yes | Yes |
| Cash Flow Reporting | No | Yes |
| Tax Estimate/Forecast | Yes | Yes |
| AI-Powered Features | Coming soon | Partial |
Winner: RentalBux for direct landlord financial reports. RentalBux gives landlords direct access to their own financial statements.
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.
Capium's Collaborative Features
Capium is accountant focused. The accountant is the primary user, and the landlord (as a client) accesses Capium 365 as a data capture and record-keeping layer that feeds directly into the accountant's compliance workflow. For practices managing large numbers of landlord and sole trader clients under MTD, Capium's collaboration infrastructure — unlimited users, client portal, bulk document requests, multi-client submission dashboard, and 6-day-a-week support — is genuinely best-in-class.
| Feature | RentalBux | Capium |
|---|---|---|
| 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: Capium for practice-side collaboration tools; RentalBux for direct landlord agent access — Capium's practice suite provides unmatched multi-client management, unlimited users, client portal, and bulk document workflows for accountancy firms. RentalBux provides straightforward agent filing for individual landlord clients without requiring a full accountancy practice infrastructure.
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.
PaTMa's Ease of Use
Capium is consistently described by users as easy to use and intuitive for an accounting practice platform. User reviews on Capterra and G2 praise its usability, integration between modules, and strong customer relationship with management. Capium offers 6-day-a-week support (phone: 020 3322 5578), free onboarding for all clients, and proactive updates via a community Facebook group. The platform was established in 2013 and has a ten-year+ track record.
| Feature | RentalBux | Capium |
|---|---|---|
| Phone Support | Yes | Yes |
| Chat Support | Yes | Yes |
| 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 Capium Offers
Full-Suite Practice Accountancy Platform in One Integrated System
Capium uniquely integrates Accounts Production, Corporation Tax, Self Assessment, Payroll, Practice Management, Company Secretarial, AML, MTD for VAT, MTD for Income Tax, and bookkeeping in a single cloud platform — with data flowing between modules automatically. This eliminates the need for multiple separate software products and is the core value proposition for UK accounting practices.
MTD for VAT (9-Box Submissions with Spreadsheet Bridging)
Capium supports MTD for VAT with automated 9-box calculations and spreadsheet bridging alongside its MTD IT offering.
Accounts Production — Statutory Accounts to Companies House
Capium's Accounts Production module produces full, abbreviated, and abridged year-end accounts and files them directly to Companies House — recognised by both HMRC and Companies House. This is an accountancy practice tool with no equivalent in a landlord platform.
Self Assessment (SA100, SA800, SA900, SA109)
Capium's Self Assessment module automatically pulls through financial data for all SA forms and submits directly to HMRC, supporting sole traders, partnerships, trusts, and landlords. All form types and client categories are covered.
Payroll with Auto-Enrolment and RTI Submissions
Capium's Payroll module handles payroll calculations, auto-enrolment, and Real Time Information (RTI) submissions — covering the full payroll compliance cycle for employment-based clients.
Anti-Money Laundering (AML) — KYC, Risk Assessments, Sanctions and PEP Checks
Capium's AML module provides Know Your Customer checks, risk assessments, and third-party client verification including sanctions and PEP (Politically Exposed Persons) screening — essential compliance tooling for accountancy practices under UK AML regulations.
Bulk Document Requests with Client Submission Tracking
Accountants using Capium 365 can send batched document requests to multiple clients simultaneously and track which have responded. This is a material efficiency gain for practices managing large volumes of MTD IT client work.
Multi-Client MTD Submission Dashboard
Capium's practice-side dashboard gives accountants full visibility of MTD IT submission status across all clients — showing quarterly update status, outstanding obligations, and deadline positions in one view.
Capium 365 — Client-Facing Bookkeeping with Unlimited Bank Feeds and Document Storage
Capium 365 provides clients with unlimited bank feeds (free with licence), unlimited user access at no additional cost, unlimited document storage, and full integration with the practice suite — a comprehensive client collaboration tool that feeds directly into the accountant's compliance workflow.
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 Capium?
Capium is the better choice for:
Accountancy Practices Managing Multiple Landlord and Sole Trader Clients
Capium is purpose-built for practices. Its multi-client MTD IT dashboard, bulk document requests, structured submission workflows, unlimited users, free onboarding, and 6-day support make it one of the most capable UK practice platforms for managing MTD IT at scale.
Practices That Need a Full Integrated Compliance Suite
If your practice needs Accounts Production, Self Assessment, Corporation Tax, Payroll, AML, Company Secretarial, MTD for VAT, and MTD for Income Tax in one integrated platform — Capium's full suite is designed exactly for this. No other platform in this comparison series covers this breadth.
Landlords Whose Accountant Already Uses Capium
If your accountant uses Capium and can provision Capium 365 for you, the client-facing bookkeeping tool with unlimited bank feeds, receipt capture, and automated categorisation provides a capable digital record-keeping solution that integrates seamlessly with your accountant's compliance workflow.
Accountants Seeking the Lowest Total Cost of Compliance Ownership
User reviews consistently highlight Capium as strong value for the combination of Accounts Production, Corporation Tax, Self Assessment, and Payroll relative to competitor platforms.