Collect the figures by return section
Enter employment, self-employment, property, dividends, savings, capital gains, pensions, Gift Aid and tax already paid.
UK Self Assessment Companion
See the tax bill before you file.
Bring the figures for your 2025/26 return together, estimate Income Tax, National Insurance, Capital Gains Tax, student loan and payments on account, then prepare a box-by-box worksheet for the official service.
£18 one-time 2025/26 return Works offline Import Methodwise backups
The actual dashboard, shown with example 2025/26 return figures.
From source figures to return boxes
See the whole tax position, not a pile of separate notes
Each section feeds the estimate, payment schedule, readiness checks and return worksheet.
Build up the bill in one calculation
Estimate Income Tax for Scotland or the rest of the UK, Class 4 National Insurance, Capital Gains Tax and student-loan repayment.
See the January amount and what follows
Separate the balancing payment from the first payment on account, then see the next July and January instalments.
Prepare figures box by box
Review return-shaped sections, copy individual figures, print the worksheet and keep the source behind each amount nearby.
Find gaps before opening the official service
Checks flag missing or inconsistent details and show which return sections are ready for final review.
Test the decisions around the return
Compare the trading allowance with actual expenses, test extra income, estimate set-aside and explore a reduced payment on account.
Return workspace
Move from totals to the boxes that need them
The annual worksheet groups the figures by return section and keeps copy, table and printable views in the same workspace.
- Return-shaped sections for each income source you select
- Copy individual values without retyping the whole calculation
- Readiness checks beside the figures they affect
- Printable worksheet for a final review or accountant discussion
Clear filing boundary
It prepares a 2025/26 return. It does not file one.
The companion is an organiser and estimate, not recognised filing software or tax advice. It does not connect to your Government Gateway account. Review every figure against current guidance before copying it into the official service or giving it to an accountant.
2025/26 return Use the current GOV.UK completion guideSending the return Check official filing optionsProfessional help Ask a tax adviser where needed
How it works
Build the return picture in three passes
No installation, account or subscription is required.
Choose the sections
Set your region and tax-year details, then switch on the income and adjustment sections that apply to you.
Add or import figures
Enter the totals directly or import compatible backups from selected Methodwise money and tax apps.
Review and copy
Check the estimate and payment schedule, resolve readiness flags and use the worksheet beside the official service.
A connected tax workspace
Bring the source records into the annual picture
Private by design
Your tax figures stay on your device
The companion runs locally in your browser. It has no account, cloud database, analytics, bank feed or connection to HMRC, and it does not upload income or tax details.
Imports and backups are manual files that you choose. The app cannot submit the return, take a payment or verify HMRC's record of your income. Keep regular backups somewhere separate from the downloaded app.
Frequently asked
Before you buy
Who is the companion designed for?
It is designed for UK individuals who need to organise figures from one or more common Self Assessment sections before completing the official return or discussing it with an accountant.
Which tax return does it prepare?
The current edition prepares the 2025/26 return. Check the listing and app version before buying if you need a different tax year.
Does it file with HMRC?
No. It does not connect to Government Gateway or submit a return. It prepares an estimate and a box-by-box worksheet for you to review and copy.
Is the tax estimate guaranteed?
No. The estimate is based on the figures and choices you enter and cannot model every personal circumstance. Check it against current guidance and seek professional advice where needed.
Can it import other Methodwise apps?
Yes. It can read compatible backup files from selected Methodwise products, including the Sole Trader Ledger and Mileage Tracker, through a review-first import flow.
Does it support Scottish Income Tax?
Yes. Choose Scotland or the rest of the UK for the Income Tax calculation. Other parts of the estimate use the applicable UK-wide treatment built into the 2025/26 edition.
Which computers and browsers does it work on?
It works on Windows, Mac and Linux computers in a modern version of Chrome, Edge, Safari or Firefox.
What is included in the download?
The single-file UK Self Assessment Companion app, a quick-start guide, and licence and support details. Etsy delivers the download after purchase.
Turn scattered tax figures into one return-ready worksheet
Buy UK Self Assessment Companion on Etsy, download it once and prepare your 2025/26 figures without an account or subscription.
Buy on Etsy