TapTax vs RentalBux
Two free MTD plans, two very different catches
RentalBux Free is one of only three products on HMRC directory that are free, have a mobile app, keep digital records and cover all three income sources. Its free plan is capped at one property and ends in March 2028. Here is the honest side-by-side.
Estimate your self-employed tax in seconds
See what you would owe for the year, then file the real figures with TapTax in a couple of taps.
Total turnover before expenses
Under £1,000 we use the trading allowance automatically
Estimated tax bill
£6,872
15.3% effective rate for 2026/27
- Income tax
- £5,286
- Class 4 NI
- £1,586
Take-home pay
£32,128
after tax, NI and expenses
This is an estimate using HMRC-confirmed rates for 2026/27, not your official tax calculation. TapTax is MTD-compatible, so you can connect to HMRC and file the real figures in a couple of taps.
RentalBux is the single most interesting name on HMRC's directory if you are looking at TapTax, and it is worth saying why up front rather than burying it. Of the 122 products HMRC lists, only four combine a free version, a mobile app on both platforms and all three business income sources: DIY Tax, Abridge (MTD for Excel/Sheets), Self Assessment Direct and RentalBux Free. Require native digital record-keeping as well, which rules out Abridge because it is a bridging tool rather than a record-keeper, and three are left: DIY Tax, Self Assessment Direct and RentalBux Free.
That is the quadrant TapTax occupies, so these are the products standing closest to it. RentalBux Free is the most direct neighbour of the three, because DIY Tax's free edition is capped hard (one business or property, 30 invoices and expenses, and MTD for VAT or Income Tax but not both) and Self Assessment Direct is a web-first bridging and cashbook product whose mobile flag is vendor-declared and looks inconsistent with its own site.
The differences are real, though, and they are mostly about shape rather than capability. RentalBux is a landlord product that added self-employment. TapTax is a tax-filing product that covers property. And the two free plans, which look equivalent in a feature grid, carry very different conditions once you read them properly.
- RentalBux is listed on HMRC's MTD directory twice, as RentalBux and RentalBux Free, and both are graded with 15 of the 16 tax-return items ready.
- Free plus a mobile app plus all three income sources is four products on the directory; requiring native digital records too narrows it to three, RentalBux Free among them. That is the quadrant TapTax occupies.
- The RentalBux free plan is capped at one property and is described as free until March 2028, the month before the final MTD threshold lands.
- RentalBux paid runs £4.50/mo landlord, £5.75/mo self-employed or £9.50/mo for both, billed yearly, as checked August 2026; TapTax is £0, £4.99 or £9.99 a month.
- RentalBux is property-first with self-employment added; TapTax is tax-first and mobile-first, MTD-compatible and going through HMRC's recognition process.
How HMRC's own directory grades RentalBux
This is not our assessment. HMRC publishes a feature grid for every product on its find-MTD-software service, using its own three-state scale of ready now, in development, or not included. We scraped all 122 listings on 5 August 2026 and RentalBux appears twice.
RentalBux Free
£0(checked August 2026)
- Free version: yes
- Android; Apple iOS: yes
- Sole trader income: yes
- UK property income: yes
- Foreign property income: yes
- Keeps digital records: yes
15/16 tax-return items ready.
HMRC MTD for Income Tax directory, scraped 5 August 2026. Feature flags are vendor-declared. Vendor site
Free plan covers one property and is described as free until March 2028. Paid plans are £4.50/mo landlord, £5.75/mo self-employed or £9.50/mo for both, billed yearly.
RentalBux
£4.50 to £9.50/mo billed yearly(checked August 2026)
- Free version: no
- Android; Apple iOS: yes
- Sole trader income: yes
- UK property income: yes
- Foreign property income: yes
- Keeps digital records: yes
15/16 tax-return items ready.
HMRC MTD for Income Tax directory, scraped 5 August 2026. Feature flags are vendor-declared. Vendor site
Paid plans are free until your first MTD submission, so the trial is genuinely usable rather than read-only.
HMRC lists what each vendor declares. Feature flags, mobile-app support in particular, are vendor claims rather than verified facts, and listings change. Check with the vendor before you buy. Data: HMRC find-MTD-software service (tax.service.gov.uk), scraped 5 August 2026.
Two things stand out. The first is the 15 out of 16 return items, which puts RentalBux in the top cohort of the entire directory: 3 of 122 (2%) products have all 16, and only 27 of 122 (22%) have nine or more. The second is that the free listing carries the same grades as the paid one, which is unusual. Plenty of products on the directory list a free version that quietly withholds the thing you actually need.
The completeness cliff, and why 15 of 16 matters
Most buyers assume that anything on HMRC's directory can handle their tax return. It cannot, and the gap is much larger than the market lets on.
87of 122 (71%)cannot complete a single tax-return itemHMRC MTD for Income Tax directory, scraped 5 August 2026Those products can file the four quarterly updates. They cannot complete a single one of HMRC's 16 tax-return items, which is the work of finishing the year: interest, dividends, pension income, Construction Industry Scheme deductions, capital gains, student loan, marriage allowance and the rest. If your tax life has anything beyond trading or rental income in it, a product on that side of the cliff means a second tool at year end.
RentalBux is firmly on the right side of that line. So are Kletta, untied, Clear Books, FreeAgent, QuickBooks, TaxHeaven and My Tax Digital. We wrote up the full picture, including which products sit where, in our analysis of all 122 HMRC-listed MTD tools, and you can filter the whole list yourself on the MTD software directory.
TapTax's own honest position on that axis: mid-pack today. TapTax covers all three income sources, keeps digital records, files standard and calendar quarters and runs on iOS and Android, but roughly six to eight of the 16 return items are live, with pensions income, CIS, capital gains and partnership income still to come. RentalBux is ahead of TapTax on return-item completeness right now. Saying otherwise would be the kind of claim this page exists to debunk.
- Tax-return items (MTD ITSA)
- The 16 categories HMRC grades separately on its software directory, covering everything outside your quarterly business updates: UK interest, employment (PAYE), UK dividends, state and private pension income, partnership income, foreign dividends and interest, pension contributions, Construction Industry Scheme, charitable giving, capital gains, student loan, marriage allowance, voluntary Class 2 NI and the High Income Child Benefit Charge. A product with none of these can file quarterly updates but cannot finish your return.
Pricing in detail, checked August 2026
| TapTax Free | TapTax Starter | TapTax Pro | RentalBux Free | RentalBux paid | |
|---|---|---|---|---|---|
| Monthly cost | £0 | £4.99 | £9.99 | £0 | £4.50 landlord, £5.75 self-employed, £9.50 both |
| Billing | Monthly | Monthly | Monthly | n/a | Yearly for these rates |
| Approx. annual cost | £0 | £59.88 | £119.88 | £0 | £54 to £114 |
| Free plan cap | Core MTD features | n/a | n/a | 1 property, free until March 2028 | n/a |
| Includes MTD submission on free | Yes | n/a | n/a | Yes | n/a |
| Sole trader income | Yes | Yes | Yes | Ready (HMRC grade) | Ready (HMRC grade) |
| UK property | Yes | Yes | Yes | Ready (HMRC grade) | Ready (HMRC grade) |
| Foreign property | Yes | Yes | Yes | Ready (HMRC grade) | Ready (HMRC grade) |
| Return items ready | 6 to 8 of 16 | 6 to 8 of 16 | 6 to 8 of 16 | 15 of 16 | 15 of 16 |
| Mobile app | iOS and Android | iOS and Android | iOS and Android | iOS and Android | iOS and Android |
| HMRC directory status | Not listed; recognition in progress | Not listed; recognition in progress | Not listed; recognition in progress | Listed | Listed |
RentalBux prices are from its published pricing as checked in August 2026 and are the yearly-billed rates. Feature grades in the RentalBux columns are HMRC's, from the 5 August 2026 scrape, not the vendor's marketing. TapTax pricing is our own published pricing.
On raw cost these two are close enough that price should not decide it. £54 a year against £59.88 a year is not a meaningful difference for anyone whose tax bill runs to four figures. What should decide it is the free plan's shape and what you are actually trying to do.
The two free plans, read properly
Both free plans clear the bar that most do not: they include the submission. That sounds obvious and it is not. The directory has 31 of 122 (25%) products listing a free version, and a good number of those free tiers are record-keeping only, bank-account acquisition deals, or trials that cannot file.
Where they differ is in the conditions.
RentalBux Free covers one property. If you own a single flat and no self-employment, that is a complete answer at zero cost, and it is a better answer than most of the market can give you. Add a second property and you are on a paid plan. RentalBux also describes the free plan as free until March 2028, as checked in August 2026. That date is deliberate: MTD lands at £50,000 in April 2026, £30,000 in April 2027 and £20,000 in April 2028, so a free window ending March 2028 spans the entire phase-in and closes just as the last wave arrives. It is a well-judged land-grab, and it is time-limited by design.
TapTax's free tier is not property-capped and does not carry an end date, but it comes with the caveat we put on every page: TapTax is MTD-compatible and going through HMRC's recognition process, so it is not on the directory yet. If you need to file a live submission this month, that matters, and RentalBux is listed today.
A free tier that includes the submission is worth ten that include everything except the submission. Read the cap and the end date before you read the feature list.
Where RentalBux genuinely wins
It is property-first, and that shows in the parts of the job that are not tax. Rent tracking, tenancies and the day-to-day admin of being a landlord are the problem RentalBux started from, and a tax engine was built onto that. If you are managing several tenancies and you want the rent ledger and the MTD filing to be the same system, that integration is real and TapTax does not offer it.
It is also further along on return items, and it is listed with HMRC today. Both of those are straightforward wins that we are not going to argue around.
Where TapTax fits better
If property is one part of your income rather than the whole of it, the shape flips. TapTax was built as a tax filing product for people whose income is mixed: some trading, some rental, sometimes an overseas property, all filed from a phone in a few taps. Open banking pulls the transactions in, AI categorisation sorts them, receipt capture and CSV import cover what the bank feed misses, and the quarterly update becomes a review-and-submit rather than a data-entry evening.
The free tier is also not capped at one property, which matters if you are a landlord with two or three and no self-employment: that is precisely the case RentalBux Free does not cover and where its paid plan starts.
Before you choose either, it is worth knowing your numbers. The rental income tax calculator applies the finance-cost restriction, where mortgage interest relief is limited to a 20% credit rather than a deduction, and the sole trader calculator covers the trading side including Class 4 NIC.
Who should choose which
One rental property, no self-employment, wants zero cost. RentalBux Free, and it is not close. One property is exactly the cap, the submission is included, and it is listed with HMRC now. Diarise a check before March 2028.
Two or more properties, no self-employment. RentalBux Free does not reach you, so you are comparing RentalBux at £4.50 a month billed yearly against TapTax Free or Starter. If you want tenancy management alongside, RentalBux. If you want the cheapest clean route to four quarterly updates and a final declaration, start on TapTax's free tier and see whether you ever need to pay.
Mixed trading and rental income. TapTax is built for this shape and prices it as one product rather than two add-ons. RentalBux charges £9.50 a month billed yearly to cover both, which is still reasonable, but the product is landlord-shaped and the self-employment side is the addition.
An overseas property. Only 60 of 122 (49%) of the directory can report foreign property at all. Both of these can. That alone rules out most of the alternatives you will find recommended elsewhere.
Needs to file a live submission this week. RentalBux, or another listed product. TapTax's recognition is in progress and we will not tell you otherwise.
The bottom line
RentalBux is a genuinely good product and the closest thing TapTax has to a structural twin on HMRC's directory: free, mobile, all three income sources, and further ahead than us on return items today. If you have one rental property, take the free plan and note the March 2028 date.
TapTax is the better fit when property is part of a mixed tax life rather than all of it, when you have more than one property and do not want to pay for tenancy tooling you will not use, or when you want a free tier without a property cap. The honest caveat stands: TapTax is MTD-compatible and going through HMRC's recognition process, so confirm current status before you rely on it for a live filing.
Either way, choose from the data rather than the marketing. Every product on HMRC's list, with its real grades, is in the MTD software directory.
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