RentalBux vs. Otis Tax
Which MTD Software Is Better for UK Landlords vs. Self-Employed?
Overall Winner: RentalBux
RentalBux is the more complete MTD software for landlords and sole traders who need an all-in-one 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. Otis Tax is a lightweight, spreadsheet-based bridging tool designed for self-employed individuals and freelancers who want the simplest possible path to MTD compliance — but it lacks property management, bank feeds, invoicing, and the accounting depth that landlords require.
At-a-Glance MTD Software Comparison
Key differences between RentalBux and Otis Tax across MTD compliance, property management, bookkeeping, pricing, and landlord-specific features.
| Feature | RentalBux | Otis Tax |
|---|---|---|
| Software Type | Property/Landlord Platform | Bridging/Submission Tool |
| Target Users | Landlords, Sole Traders, Letting Agents | Sole Traders, Freelancers, Contractors |
| Income Sources Supported | Sole Trader + UK Property + Foreign Property | Sole Trader + UK Property + Foreign Property |
| Free MTD Software Plan | Free until March 2028 (1 property) | Free to sign up; pay per submission |
| 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 | No |
| Spreadsheet Import/Export | Yes | Yes (core workflow) |
| Platform | Web, iOS, Android | Web |
| GDPR Compliant | Yes | Yes |
What Is RentalBux? What Is Otis Tax?
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 Otis Tax?
Tax returns are complicated, Otis makes them easy.
Otis Tax (otistax.co.uk) is a UK-based, HMRC-recognised MTD bridging software designed for the self-employed — sole traders, freelancers, and contractors — who want the simplest possible route to MTD compliance without switching to full accounting software. Made in London and operated by This is Otis Ltd, the platform allows users to continue keeping their records in Excel or CSV spreadsheets and submit quarterly updates to HMRC by uploading those spreadsheets directly into Otis.
Otis Tax's core philosophy is radical simplicity: most users complete a quarterly update in under 10 minutes. Upload your spreadsheet, review the income and expense summary, and submit directly to HMRC. The platform automatically updates an estimated tax liability after every upload, helping users avoid year-end surprises. At the end of the tax year, Otis pre-populates the Final Declaration from quarterly data, replacing the old Self Assessment return. Otis supports multiple income streams — a user with both self-employment and property income can manage both from the same account, with separate dashboards for each.
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 (sole trader, UK property, foreign property)
- Extremely simple: upload spreadsheet, review, submit in under 10 minutes
- Pay-as-you-go or annual bundle pricing — no subscription lock-in
- Real-time estimated tax liability updates after every upload
- Final Declaration pre-populated from quarterly data
- Supports multiple income sources (self-employment + property)
- Deadline reminders for each quarter
- Free to sign up; only pay when ready to submit
- Keeps existing spreadsheet workflow intact
- Foreign property support included
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
- No property management features whatsoever
- No bank feeds or automated transaction matching
- No receipt capture, OCR, or AI categorisation
- No invoicing or payment collection
- No accountant/agent portal or multi-user access
- No chart of accounts, journal entries, or formal P&L
- No phone support — email contact only
- Not suitable for landlords needing full accounting
- No joint ownership or profit-splitting capability
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 Otis Tax Handles MTD Compliance
Otis Tax covers sole trader income, UK property income, and foreign property income for MTD purposes, with quarterly updates and final declarations submitted directly to HMRC. Its spreadsheet-upload workflow means users do not need to change how they keep records — they simply upload their existing Excel or CSV file and Otis validates and submits it. Otis also provides an end-of-period statement process and a pre-populated Final Declaration at year end. However, Otis does not support agent filing, accountant access, or multi-user collaboration.
| Feature | RentalBux | Otis Tax |
|---|---|---|
| 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 | No |
Winner: RentalBux — While both platforms cover the same income types for MTD, RentalBux adds structured digital record keeping, automated bookkeeping, and agent filing capability — giving landlords and their accountants a decisive advantage for full MTD compliance.
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.
Otis Tax: No Property Management Features
Otis Tax does not offer any property management functionality. It supports property income from a tax submission perspective — landlords can record rental income and expenses in a spreadsheet and submit them via Otis — but there is no tenant management, no rent tracking, no maintenance logging, no compliance document alerts, no joint ownership tools, and no HMO support. For a landlord managing even a single property with any complexity, this is a significant limitation.
| Feature | RentalBux | Otis Tax |
|---|---|---|
| Property Portfolio Management | Yes | No |
| Tenant Management | Yes | No |
| Rent Tracking | Yes | No |
| Property Expense Allocation | Yes | No |
| Multiple Property Support | Yes | Yes |
| 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 — Otis Tax has no property management capability. For any landlord who needs to manage tenancies, track rent, handle joint ownership, or monitor compliance, RentalBux is the only viable choice of the two.
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.
Otis Tax: Spreadsheet Upload — No Native Bookkeeping
Otis Tax does not include any bookkeeping features. The platform's entire record-keeping model relies on the user maintaining their own spreadsheet (Excel or CSV) and uploading it to Otis for validation and submission. There is no chart of accounts, no journal entries, no bank reconciliation, no bank feeds, and no automated transaction categorisation. Otis stores digital backups of uploaded spreadsheets for compliance purposes, which satisfies HMRC's digital record-keeping requirement — but only if the spreadsheet itself has been maintained accurately.
| Feature | RentalBux | Otis Tax |
|---|---|---|
| Cash Basis Accounting | Yes | Via spreadsheet |
| Chart of Accounts (Pre-built, Landlord-Tailored) | Yes (pre-built + custom) | |
| 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 | No |
| Xero Integration | No | No |
| Spreadsheet Import/Export | Yes | Yes |
| Digital Record Storage | Yes | Yes |
| Chart of Accounts (Pre-built) | No |
Winner: RentalBux — RentalBux provides a complete, structured accounting backbone. Otis Tax is a submission tool only; bookkeeping is entirely the user's own responsibility in their spreadsheet.
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.
Otis Tax: No Invoicing or Expense Automation
Otis Tax has no invoicing capability, no receipt capture, no OCR, and no AI categorisation. Expense tracking is handled entirely by the user in their own spreadsheet before upload. The platform does not automate any aspect of bookkeeping — its role begins when the user uploads a completed spreadsheet for submission.
| Feature | RentalBux | Otis Tax |
|---|---|---|
| Invoice Creation & Sending | Yes | No |
| Invoice Customisation/Branding | Yes | No |
| Online Payment Collection | Yes | No |
| Payment Tracking/Reminders | Yes | Yes |
| Expense Tracking | Yes | Via spreadsheet only |
| Receipt Capture (OCR/Photo) | Yes | No |
| Expense Categorisation | Yes | No |
| Automated Transaction Matching | Yes | No |
| Mileage Tracking | No | No |
| AI Auto-Categorisation | Coming soon | No |
Winner: RentalBux — Otis Tax offers no invoicing, receipt capture, or expense automation whatsoever. For landlords who want to maximise allowable deductions and minimise manual admin under MTD, RentalBux is the only viable choice.
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.
Otis Tax: Real-Time Tax Estimate Only
Otis Tax provides a single reporting feature: a real-time estimated tax liability that updates after every spreadsheet upload. This is a genuinely useful feature for sole traders who want to know approximately what they owe HMRC throughout the year. Beyond this estimate, Otis Tax produces no formal financial reports — no P&L, no balance sheet, no dashboard, no portfolio overview.
| Feature | RentalBux | Otis Tax |
|---|---|---|
| Profit & Loss Report | Yes (formal) | No |
| Balance Sheet | Yes | No |
| Trial Balance | Yes | No |
| Dashboard/Overview | Yes | No |
| Real-Time Financial Data | Yes | Estimated tax liability only |
| Cash Flow Reporting | No | No |
| Tax Estimate/Forecast | Yes | Yes |
| AI-Powered Features | Coming soon | No |
Winner: RentalBux- RentalBux leads on all formal accounting reports. Otis Tax's running tax estimate is its sole reporting feature, which suits self-employed individuals with simple needs but is wholly insufficient for landlords.
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.
Otis Tax's Collaborative Features
Under Making Tax Digital, many landlords work closely with accountants or letting agents to manage quarterly submissions and year-end declarations. The ability to delegate filing, share access, and manage records on the go are practical necessities — and this is where the gap between RentalBux and Otis Tax becomes especially stark.
| Feature | RentalBux | Otis Tax |
|---|---|---|
| Accountant/Advisor Portal | Yes | No |
| Multi-User Access | Yes | No |
| Agent Filing on Behalf | Yes | No |
| Bank Integration | Yes | No |
| Platform | iOS, Android | Web Browser only |
| Web Browser Access | Yes | Yes |
| FCA Regulated | Yes | Yes |
| GDPR Compliant | Yes | Yes |
Winner: RentalBux — Otis Tax is a single-user, web-only platform with no accountant portal, no agent filing, and no mobile app. For any landlord working with a letting agent or accountant, or who wants mobile access, RentalBux is the only option.
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.
Otis Tax's Ease of Use, Customer Support & Security
Otis Tax is designed around maximum simplicity — upload a spreadsheet, review, submit. The platform is web-only with no mobile app. Customer support is via email at team@otistax.co.uk; there is no phone support or live chat listed on the platform's website. Otis Tax describes itself as still in active development, with plans to integrate with fintech systems and additional APIs in future. No Trustpilot rating is publicly available for Otis Tax at the time of publication.
| Feature | RentalBux | Otis Tax |
|---|---|---|
| Phone Support | Yes | No |
| Chat Support | Yes | No |
| Email Support | Yes | Yes |
| Help Centre/Knowledge Base | Yes | Blog/guide articles |
| FCA Regulated | Yes | Yes |
| 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 Otis Tax Offers
True Pay-as-You-Go Pricing
Otis Tax's £25-per-submission model means users only pay when they actually submit. There are no monthly subscription fees, no commitment, and no charge for signing up or setting up the account. For a sole trader who files infrequently or wants to test the platform before committing, this is a genuinely unique pricing structure.
Spreadsheet-First Workflow
Otis Tax is built specifically for users who want to keep their existing spreadsheet records and simply need a compliant submission bridge to HMRC. No new software to learn, no data migration, no change to existing habits — just upload and submit.
Extreme Simplicity
Otis claims most users complete a quarterly update in under 10 minutes. For a sole trader with straightforward income and no property complexity, this frictionless experience is a genuine advantage over full accounting platforms.
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 Otis Tax?
Otis Tax is the better choice for:
Sole Traders and Freelancers with Simple Income
If you are self-employed with a single business, already maintain records in a spreadsheet, and simply need a compliant way to submit four quarterly updates to HMRC per year — Otis Tax delivers exactly this with minimal cost and minimal effort.
Contractors Who Don't Want to Change Their Workflow
tis Tax's spreadsheet-upload model means zero disruption to existing record-keeping habits. No new software to learn, no data migration.
Budget-Sensitive Self-Employed Individuals
At £80/year for a sole trader with one income source, Otis Tax is one of the lowest-cost HMRC-recognised MTD submission options available.
Users Who Prioritise Simplicity Over Features
If accounting software feels overwhelming and you simply want to stay HMRC-compliant with minimum admin, Otis Tax's promise of a 10-minute quarterly update is genuinely attractive.
Self-Employed Individuals Who Already Have an Accountant
If your accountant handles your books and you just need the submission layer, Otis Tax covers the compliance requirement at low cost — though note that your accountant cannot access Otis Tax on your behalf (no agent portal).