File your SA100 Self Assessment tax return
HMRC-recognised Self Assessment tax return software for company directors and employees. Enter your salary, dividends and savings, watch your tax calculated live, and submit your SA100 straight to HMRC. Free while we launch.
File your Self Assessment online — free while we launch
Start your Self Assessment return- HMRC recognised
- Live tax calculation
- Salary, dividends & savings
- Free during launch
Self Assessment tax return software for directors
Salary and dividends
Built for the classic director's return — PAYE salary and dividends from your own company. Enter the figures once; we work out the tax across the basic, higher and additional rate bands.
Live tax calculation
Your income tax, dividend tax and the balance to pay update as you type — calculated on the server, never guessed in the browser. No more reconciling against HMRC's online form at the end.
Scottish and Welsh rates
Tell us your taxpayer status and we apply the right rate bands — Scottish income tax on your employment income, UK rates on savings and dividends, exactly as HMRC expects.
Savings interest
Add your gross savings interest and we apply your Personal Savings Allowance and the starting rate for savings automatically.
The common adjustments
Student Loan repayments, the High Income Child Benefit Charge, pension contributions, Gift Aid and Marriage Allowance are all handled and flow through to the right boxes.
Submitted straight to HMRC
We file your SA100 through the live HMRC Self Assessment service and track it to acceptance — you get the confirmation, not a screenshot of a portal.
How it works
From your figures to a filed SA100 in minutes
1. Enter your income
Sign in and add your salary, dividends and savings. If you're a director, your company details prefill from Companies House.
2. Check your tax
See your full Self Assessment calculation — income tax, dividend tax, and the balance to pay — before anything is sent.
3. Submit your SA100
File directly to HMRC with your Government Gateway details. We track the submission to acceptance and confirm when it's done.
More Happy. Tiny Tax.
A director's tax return shouldn't mean wrestling with HMRC's eight-page form. Enter your salary, dividends and savings, see your tax worked out live, and submit your SA100 straight to HMRC. You answer a few questions; we file the return.
Free while we launch
File your SA100 Self Assessment return to HMRC at no cost while we launch. We’ll introduce pricing later — and we’ll always show you the price before you pay.
Frequently asked questions
What is the SA100?
The SA100 is the main HMRC Self Assessment tax return — the form individuals use to report income that isn't fully taxed through PAYE, such as dividends from their own company. TinyTax fills in the SA100 (and the employment pages) from the figures you enter and submits it to HMRC for you.
Who is this for?
Company directors and employees who need to file a Self Assessment return for salary, dividends and savings income — the typical owner-director return. If your tax affairs are limited to those sources plus the common adjustments below, you're exactly who this is built for.
What income and adjustments are supported?
Employment (salary and PAYE tax deducted), dividends, and savings interest, plus Student Loan repayments, the High Income Child Benefit Charge, pension contributions, Gift Aid and Marriage Allowance. Scottish and Welsh taxpayer rates are applied automatically.
What is not supported yet?
Self-employment (sole trader), rental and property income, capital gains, and foreign income are not supported yet. If your return needs any of those, this isn't the right tool for you this year — we'd rather tell you up front than have you start a return we can't file.
Is this recognised by HMRC?
TinyTax is HMRC-recognised for Self Assessment and submits through the live HMRC Self Assessment service, the same channel HMRC's own online filing uses. You file under your own Government Gateway credentials.
Do I need my own Government Gateway login?
Yes. You file your own SA100 using your personal Government Gateway user ID and password and your Unique Taxpayer Reference (UTR). If you don't have a UTR yet you'll need to register for Self Assessment with HMRC first.
How much does it cost?
Self Assessment filing is free while we launch the SA100 — file your return to HMRC at no cost. We'll introduce pricing later, and we'll always tell you the price before you pay anything.
How is my tax calculated?
On the server, using the same calculation engine across every return — never in your browser. Income tax uses your taxpayer status (UK, Scottish or Welsh) and rate bands; dividends use the dividend allowance and dividend rates; savings use your Personal Savings Allowance. You see every figure before you submit.
Ready to file your SA100?
Start your Self Assessment return now — free while we launch.
Start your Self Assessment return