In one paragraph: price the pages, not "a tax return". Start with a base fee for the main return (personal details, interest, review with the client, filing), then add a set amount for each page it needs: each employment (SA102), each self-employment (SA103S or SA103F), each partnership share (SA104), property (SA105, more for each extra property), foreign income (SA106), each capital gains disposal (SA108) and residence (SA109). Multiply the bookwork for self-employment and property when the client sends bank statements or a bag of receipts instead of totals. Add a written surcharge for records that arrive in December or January, and quote Making Tax Digital quarterly updates as a separate yearly service. Work each price out from your minutes and your hourly rate: the calculator below does the sums.
Jump to: Free fee calculator · The method · What each page costs you · Records and late surcharges · Late-records clause · MTD for Income Tax · Price list · If you're hiring someone · Mistakes · Using AI · FAQ
Free calculator: a fixed fee for one client's Self Assessment return
Tick what the return contains and how the records will arrive. Results update as you type. The minutes are starting guesses, so open "Your own minutes" and replace them once you've timed a few returns. Nothing you type leaves your browser.
What's on the return
The records
Late-records surcharges
Your own minutes
The fee
Quote email
Late-records clause for your engagement letter
Your price list
Each item at your rate and contingency, from categorised records, rounded up to the next £5.
The method: base fee plus pages, from your own minutes
A single "£X per tax return" fee is the reason so many bookkeepers lose money in January. Returns differ hugely: an employee with a bit of interest takes under two hours, while a landlord with four flats and a share sale can take a day. Clients accept different prices once they can see why.
- Know your hourly rate. If you haven't worked it out from the income you need and the hours you can really bill, do that first with the bookkeeping fee calculator. Self Assessment work all lands in about ten weeks, so it's the worst place to undercharge.
- Time a few real returns. Track the minutes for three or four of last year's returns, page by page, including the chasing and the call to explain the bill. Use those in "Your own minutes".
- Price the main return, then each page. Every return has the main SA100 (personal details, interest and dividends, reliefs, review, filing). Each supplementary page adds a known chunk.
- Multiply the bookwork, not the whole return. Messy records make self-employment and property slow, not the P60 or the share sale. The calculator only applies the records multiplier to those pages.
- Add contingency and a written late surcharge. Then round up and quote one fixed fee with the assumptions in writing.
| Worked example (rate £40 an hour, 10% contingency) | Minutes |
|---|---|
| Main return, review and filing | 45 |
| One self-employment, short pages, from bank statements and receipts (90 × 1.6) | 144 |
| Queries, chasing and explaining the bill | 30 |
| Total 219 minutes, plus 10% contingency | 241 (4 hours) |
| Records by 30 November: 4.0 hours × £40, rounded up | £165 |
| Records in December (+15%) | £185 |
What each page costs you, and what makes it slow
These are the pages of the SA100 tax return listed on gov.uk. Your software shows them as sections, but the time drivers are the same.
| Page | Starting guess | What makes it take longer |
|---|---|---|
| Main return (SA100) | 45 min | New clients, changes of address or name, Gift Aid and pension relief to check, a long review call. |
| Employment (SA102) | 15 min each | Missing P60s, benefits on a P11D, several jobs, expenses claims, company directors. |
| Self-employment, short (SA103S) | 90 min each, from totals | Records that need categorising, mixed personal and business accounts, use-of-home and vehicle claims, capital allowances. Short pages are only for turnover below the VAT threshold (£90,000). |
| Self-employment, full (SA103F) | 150 min each, from totals | Balance sheet figures, stock, losses, more than one business, adjustments. |
| Partnership (SA104) | 20 min each | Usually quick if the partnership return is done; slow if you're waiting on it. |
| UK property (SA105) | 60 min, plus 30 per extra property | Joint ownership splits, finance costs (which get a basic-rate tax credit, not a deduction), repairs versus improvements, furnished holiday lets in earlier years. |
| Foreign (SA106) | 60 min | Foreign tax credit relief, exchange rates, overseas pensions or rental income. |
| Capital gains (SA108) | 45 min per disposal | Share pools, crypto, missing purchase costs, private residence relief. A UK residential property sale also needs a separate return within 60 days of completion (gov.uk): price that as its own job. |
| Residence (SA109) | 90 min | Statutory residence test, split years, the new foreign income and gains rules. |
| Reduce payments on account (SA303) | 15 min | Explaining to the client why a lower claim can mean interest later. |
The minutes are planning assumptions, not survey data. Software, experience and the client all change them, which is why the calculator lets you replace every one.
Records quality and late surcharges
Two things wreck Self Assessment pricing: the records come in a worse state than you assumed, and they come too late. Price both openly.
Records quality
| What the client sends | Multiplier on self-employment and property |
|---|---|
| Categorised totals, a spreadsheet, or bookkeeping software you already keep | ×1 |
| Bank statements and receipts you have to categorise | ×1.6 |
| A bag or box of loose paperwork | ×2.2 |
If you do their bookkeeping all year, the bookwork is already done: use ×1 and price the return on its own. A client who sends a bag of receipts every year is a good candidate for monthly bookkeeping; the records-chasing guide has the emails.
Late records
The online deadline for 2025/26 returns is 31 January 2027, and the tax is due the same day (gov.uk: deadlines). Work that arrives in January has to be done in your busiest weeks, often in the evenings. A surcharge set out in advance is fair, and it moves clients earlier, which matters more than the money.
| Complete records arrive | Suggested surcharge | Why |
|---|---|---|
| By 30 November | None | Time to spread the work and ask questions. |
| In December | +15% | Fewer working days left; Christmas closures. |
| 1 to 15 January | +30% | Peak weeks; other clients' work gets pushed. |
| After 15 January | +50%, and no promise to file on time | Any missing document means a late return. |
The percentages are suggestions; set your own. Whatever you charge, tell clients the stakes: HMRC charges £100 for a late return even if no tax is due, then £10 a day after 3 months for up to 90 days, then 5% of the tax due or £300 (whichever is more) at 6 and again at 12 months. Clients who are employed or get a pension and owe less than £3,000 can have it collected through their tax code, but only if the online return is filed by 30 December 2026 (gov.uk). That's a good reason to ask for records by the end of November.
A late-records clause for your engagement letter
Put the surcharge in the engagement letter so it isn't a surprise in January. The calculator writes this with your own percentages; the default version reads:
Records and deadlines. Our fixed fee assumes we receive your complete records by 30 November 2026. If they arrive in December the fee rises by 15%, and between 1 and 15 January 2027 by 30%, because the work has to be done in our busiest weeks. If they arrive after 15 January we will do our best, add 50%, and cannot promise to file by 31 January 2027. HMRC charges a £100 penalty for a late return even if no tax is due, and that penalty is yours to pay.
Make sure it fits the rest of your letter and your professional body's guidance. The engagement letter guide has the scope and exclusions sections it sits beside.
Making Tax Digital for Income Tax: price it separately
Sole traders and landlords with qualifying income over £50,000 (from their 2024/25 return) have had to use Making Tax Digital for Income Tax since 6 April 2026, and the threshold drops to £30,000 from April 2027. They send a quarterly update for each self-employment and for their property business, then a tax return at the end of the year. The MTD guide has the thresholds, deadlines and a start-date checker.
- Quote the quarterly updates as a yearly service, priced per income source (four updates each), and show it as a monthly amount. The calculator does this when you tick MTD.
- Keep the return fee separate. The end-of-year return still needs the work on the main return, employments, gains and reliefs.
- Bookwork is the real cost. A client who sends a bag of receipts each quarter costs you that four times a year. The records multiplier applies to the updates too.
A Self Assessment price list you can publish
A published price list saves you writing every quote from scratch and filters out clients looking for the cheapest possible number. The calculator builds one at your rate; download it as a CSV. Good price lists:
- show a base fee and add-ons, so a simple return isn't overcharged and a complex one isn't underpriced;
- say "from" and what the price assumes (records as categorised totals, by 30 November);
- show the late-records surcharges and the records-quality multipliers as plain lines;
- say whether prices include VAT (if you're VAT-registered, quote "plus VAT" consistently);
- list what's not included: HMRC enquiries, amendments after filing, earlier years, 60-day property returns.
If you're hiring someone to do your return
Fees vary a lot by region, firm and how complicated the return is, and most published "average" figures are from firms selling a service, so we don't quote one. What you can do is compare like with like:
- Ask for a fixed fee in writing, with what it includes and what it assumes about your records.
- Tell them everything up front: every job, pension, rental, sale of shares or property, foreign income, Child Benefit. Each one changes the price, and leaving one out means a second bill later.
- Send tidy records early. Categorised totals by the end of November usually cost less than a bag of receipts in January.
- Check who you're dealing with: anyone doing returns for money in the UK must be supervised for anti-money laundering, so ask who their supervisor is.
- You're still responsible. If the return is late or wrong, the penalty is yours, so check it before you approve it.
Six Self Assessment pricing mistakes
- One flat fee for every return. Simple returns subsidise complex ones, and the complex ones arrive late.
- Pricing in November, discovering in January. Ask the year-end questions before you quote; the year-end questionnaire does it.
- Doing the bookkeeping for free. A bag of receipts is bookkeeping. Price it as such, or move the client to monthly bookkeeping.
- No written late surcharge. If it isn't in the letter, January clients pay the same as October ones.
- Forgetting the 60-day return. A UK property sale needs its own Capital Gains Tax return within 60 days of completion; it's a separate job, often months before the main return.
- Folding MTD updates into the return fee. Four updates per source a year is real, repeated work.
Using AI to help
AI chat tools are good at structure and wording, and unreliable on market data and tax rules. A prompt that works:
I'm a UK bookkeeper doing Self Assessment returns. My rate is £40 an hour. My minutes: main return 45, each SA102 15, SA103S 90, each rental property 60 then 30 for each extra, each capital gains disposal 45, queries 30. Bank statements multiply self-employment and property by 1.6. Records in December add 15%. Client C22 has one job, a small self-employment from bank statements, one rental flat, and records arriving in December. 1. List each item with its minutes and total them, showing the sums. 2. Add 10% contingency and the December surcharge, and give a fixed fee rounded up to the next £5. 3. Write a short, friendly quote email listing what's included and what isn't. Don't mention other firms' prices or claim anything about the market.
- Check every sum. The calculator above is a quick cross-check.
- Check any tax rule it states against gov.uk. It can be out of date.
- Use a client code, not the client's name, UTR or National Insurance number.
Get the records in by November without chasing by hand. The free records-chaser skill writes polite, firm chasers for ChatGPT, Gemini or Claude, and client-explainer explains the bill and payments on account in plain English. Set-up takes about 3 minutes, no coding.
Bookkeeper Skills Pro adds fee-review (effective rates against your target, priced quotes and fee-increase letters, using only your own numbers) and year-end-pack for the year-end checklist and client pack.
FAQ
How much should I charge for a Self Assessment tax return?
Price the pages rather than one flat fee. Work out a base fee for the main return (personal details, interest, review and filing) from the minutes it takes and your hourly rate, then add a set amount for each employment, self-employment, rental property, capital gains disposal and any foreign or residence pages. Multiply the self-employment and property work if the records are bank statements or loose receipts, and add a written surcharge for records that arrive late. The free calculator on this page does the sums from your own minutes.
Should I charge more for late records?
Yes, if you say so in advance. Work done in December and January is squeezed into your busiest weeks, and a written surcharge (for example 15% for December, 30% for early January and 50% after 15 January, with no promise to file on time) is fair and moves clients earlier. Put it in your engagement letter and in the quote. HMRC's £100 late filing penalty applies even if no tax is due, and it's the client's to pay.
Do I charge separately for Making Tax Digital quarterly updates?
Yes. Clients in Making Tax Digital for Income Tax (qualifying income over £50,000 from 6 April 2026, over £30,000 from April 2027) send four quarterly updates a year for each self-employment and for their property business, as well as the year-end return. Price the updates as a yearly service per income source, shown as a monthly amount, and keep the return fee separate.
What does an accountant charge for a Self Assessment tax return in the UK?
Fees vary widely by region, firm and how complicated the return is, and most published averages come from firms selling a service. To compare fairly, ask each one for a fixed fee in writing with what it includes, tell them about every source of income up front, and send tidy records early: categorised totals in November usually cost less than a bag of receipts in January.
Is a 60-day property Capital Gains Tax return included in the tax return fee?
It shouldn't be. When a UK resident sells a UK home or flat with a gain, the Capital Gains Tax has to be reported and paid within 60 days of completion, which is a separate return from the annual Self Assessment. Quote it as its own job, usually when the sale completes, and then include the disposal on the main return as well.
This page is general information written by an AI agent and checked on 31 October 2026 against gov.uk (Self Assessment deadlines for 2025/26 returns, the supplementary pages list, SA103S turnover limit, paying through your tax code, reducing payments on account, 60-day Capital Gains Tax returns for UK property, and the late filing penalties). Task minutes, multipliers and surcharges are planning assumptions, not measurements or market data: replace them with your own. It isn't business, legal or tax advice. Check your engagement terms against your professional body's guidance.