SA800: The Partnership Tax Return Explained

SA800 is the tax return HMRC uses for business partnerships, separate from the personal self assessment return each partner also has to file.

It runs to eight pages and covers trading income, partnership investment income, and how profits are shared out between the partners.

A partnership doesn’t pay tax on the figures reported on the SA800 instead, each partner is taxed individually on their share. The nominated partner is responsible for completing and submitting it, usually online, by the relevant deadline.

Every year, a good number of partnership tax returns go in late simply because nobody realised the SA800 works to a different rhythm than an individual’s return.

It’s easy to see why: a partnership’s income gets reported twice, once by the business on the SA800, once by each partner individually and missing that duplication is the bit some people miss when they’re setting things up for the first time.

The form itself doesn’t calculate a tax bill. It’s a declaration, splitting the partnership’s income and gains between everyone involved so that each partner can report their share on their own self assessment return afterwards.

That division of labour catches a lot of nominated partners out, since filing the SA800 can feel like the end of the job when it’s really only the middle of it.

This guide covers what’s on the form, which supplementary pages apply, how registration works, and exactly what happens if a deadline slips.

What SA800 Actually Covers

SA800 HMRC guidance (SA800 form) confirms that every partnership gets the same eight-page core form regardless of what the business does.

Extra supplementary pages only get added on top if the partnership’s income is more varied than straightforward trading. The core form splits into four sections:

• Partnership business and investment income, covering money coming in before any partner’s share is worked out.
• Partnership trading and professional income, the main section for what the business earns from doing its work.
• The partnership statement, which splits profits, losses, and other income between the named partners.
• Other information, covering declarations and any provisional figures.

In practice, most of what goes on these pages is straightforward partnership trading income — money the business earns from its day-to-day work.

You’ll need your partnership UTR number to hand before you start; HMRC issues this once the partnership registers, and it’s separate from any individual partner’s own UTR.

Who Needs to File a Partnership Return

Any UK partnership run for profit has to submit an SA800, and that covers more ground than people often expect:

• Ordinary business partnerships, where two or more people share the work and the profits.
• Limited partnerships and limited liability partnerships (LLPs), including LLPs with a mix of individual and corporate members.
• Partnerships formed to buy and let out property, increasingly common among landlords.

None of this depends on the partnership actually turning a profit. Partnership business income tax works differently from a limited company’s corporation tax bill.

The partnership itself pays nothing directly on the figures declared, so even a loss-making or temporarily dormant partnership generally still needs to file, particularly once HMRC has issued a formal notice to do so.

Skipping it because there’s “nothing to report” is one of the more common ways a partnership ends up with a penalty for no good reason.

Registering Before You Can File

The journey from SA400 to SA800 starts before any figures get reported. Most partnerships register with HMRC using the SA400 registration form, and this needs to happen by 5 October in the partnership’s second tax year. If you miss it there’s a separate penalty before you’ve even reached your first SA800 deadline.

Each individual partner also needs to register separately, using SA401, while a partner that’s a company or another partnership uses SA402 instead.

SA800 is sometimes nicknamed the nominated partner tax return, since filing it is legally that person’s job — though every partner remains liable if it goes wrong.

Once registration goes through, HMRC posts out a ten-digit partnership UTR number, which normally takes around 28 working days to arrive, worth factoring in if you’re setting up close to a filing deadline.

Picking the Right SA800 Supplementary Pages

Think of this section as your SA800 supplementary page guide — working out which SA800 supplementary pages apply depends entirely on what kind of income the partnership had that year:

• SA800(TP) — Partnership Trading and Professional Income, needed only if the partnership carried on more than one trade or profession.
• SA801 form — for partnership UK property income, including furnished holiday lettings.
• SA802 form — for partnership foreign income, covering interest, dividends, or property income from abroad.
• SA803 form — for partnership disposal of chargeable assets tax, used whenever the partnership sold shares, land, or other chargeable assets.
• SA804 form — for partnership savings, investments, and other income that doesn’t fit the trading pages.

The partnership statement itself also comes in two versions. The short statement covers partnerships with up to three partners and only trading or bank-interest income; anything bigger, or with more varied income, needs the SA800 PS partnership statement, the full version, which covers up to six partners.

Filing Online vs by Post

If you’re wondering how to file SA800, there are two routes. SA800 online filing is the faster and more common option, though (unlike an individual self assessment return) it usually needs commercial third-party software rather than HMRC’s own portal directly.

SA800 paper filing is still allowed if you’d rather post it, and you can download SA800 form as a PDF from GOV.UK if that’s the route you’re taking.

Whichever method you choose, the SA800 tax return deadline depends on it. For the 2025/26 tax year, a paper SA800 partnership tax return needs to reach HMRC by 31 October 2026, while SA800 online filing has until 31 January 2027 — three extra months for going digital.

Filing the SA800 isn’t the end of the process for any individual partner. Each partner still needs to declare their share of profit or loss using the SA104 pages on their own self assessment return, and pay any tax due by 31 January, with a second payment on account often due by 31 July if it applies.

It’s worth reading a guide to paying your self assessment tax bill alongside this one, since the two sets of deadlines rarely line up neatly with the SA800 deadline itself.

One change worth knowing if you haven’t filed for a couple of years: from the 2024/25 tax year, the cash basis became the default way of calculating trading profits for most partnerships with only individual partners (LLPs and partnerships with a corporate partner are excluded).

If your partnership has always used the accruals basis and wants to keep doing so, that now needs an active election on the return rather than being assumed.

What Happens If Your SA800 Is Late

The first SA800 penalty lands the moment the deadline passes, not three months later. HMRC charges a £100 fixed penalty per partner as soon as the return is late, whichever filing method was chosen.

That’s the detail a lot of other guidance skips, and it matters, because these penalties apply to each partner individually rather than once to the return as a whole. A partnership with four partners can be looking at £400 before any daily penalties even start.

If the return still isn’t in, further SA800 late filing penalty tiers follow, again per partner:

• More than three months late — £10 for each additional day, up to a maximum of £900 over 90 days.
• More than six months late — a further fixed £300.
• More than twelve months late — another fixed £300.

Unlike an individual’s self assessment penalties, these don’t scale up with a percentage of tax owed.

HMRC’s own guidance notes that because a partnership doesn’t have a tax bill of its own, the tax-geared version of the penalty can’t apply here, it stays a flat £300 at each stage, whatever the partnership’s profits.

HMRC can cancel a penalty where there’s a genuine reasonable excuse. Examples include a bereavement, a serious illness, or a failure on HMRC’s own systems tend to be accepted but you’ll need to appeal it rather than assume it’ll be waived automatically.

Before You File

The HMRC partnership tax return process covers a lot of ground for an eight-page form: it declares the partnership’s income, splits it between partners, and pulls in extra supplementary pages depending on what the business earned.

Getting the paperwork right starts with registration, runs through choosing the correct supplementary pages, and ends with hitting whichever deadline applies to your filing method.

Because the return itself doesn’t calculate what any individual partner owes, filing the SA800 is only half the job — each partner still needs to complete their own self assessment return and pay any tax due.

If you’re the nominated partner and this is your first time filing, it’s worth reading the partnership tax guide beforehand to understand exactly where your responsibilities start and end.

Key Takeaways

The main SA800 points to consider:

• SA800 is the partnership’s own return; it doesn’t calculate what any partner owes, so each partner still needs to file their own self assessment (SA104) afterwards.
• Registration comes first, through SA400, with a 5 October deadline in the partnership’s second tax year.
• Which SA800 supplementary pages apply — SA801 to SA804, or the full SA800(PS) statement — depends on the partnership’s income sources that year.
• Paper SA800 returns are due 31 October, online returns 31 January, both following the end of the tax year.
• Late filing triggers an immediate £100 penalty per partner, rising to £10 a day after three months and further £300 penalties at six and twelve months.
• HMRC can cancel penalties for a genuine reasonable excuse, but only on appeal — they aren’t waived automatically.

Common SA800 questions

Once the core form is filled in, it’s usually the edge cases that catch people out — the scenarios HMRC’s own guidance covers but the main sections of the SA800 don’t really spell out.

What happens if a partner joins or leaves the partnership partway through the year?

The partnership statement still needs to reflect everyone who was a partner at any point during the return period, with profits and losses allocated based on how long each person was actually a partner. A partner who leaves part-way through still needs their share reported for the time they were involved, even if they’re not there by the time the SA800 gets filed.

Anyone joining a partnership for the first time also needs to register separately using SA401 before their share of the profits can be correctly reported on their own tax return.

Can a partnership get extra time to file its SA800?

Sometimes, depending on when HMRC issues the notice to file. If HMRC sends the notice after 31 July, the partnership generally gets three months from the date of the notice to file, or until 31 January if that’s later.

Partnerships made up entirely of corporate partners work to a different timetable altogether — nine months for a paper return and twelve months online — while mixed partnerships with both individual and corporate members can face more complex deadlines depending on their accounting date.

Does the partnership pay tax on the profits declared in the SA800?

No. Partnerships are tax transparent, meaning the SA800 itself doesn’t generate a tax bill for the business. Each partner is taxed on their share of the profits instead — individual partners pay Income Tax and Class 2 and Class 4 National Insurance, while a corporate partner pays Corporation Tax on its share.

This is often the point that trips people up: submitting the SA800 correctly doesn’t mean anyone’s tax has actually been calculated yet, since that happens separately on each partner’s own return.

Does a high-turnover partnership have extra reporting duties?

Yes. Partnerships with annual turnover above £15 million must submit full accounts and computations alongside the SA800. Below that threshold, accounts don’t need to be submitted with the return unless HMRC specifically asks for them.

Many partnerships choose to include accounts voluntarily anyway, since they support the figures reported on the return if HMRC ever queries them.

Is the SA800 the same thing as an individual partner’s tax return?

No, and confusing the two is one of the more common misunderstandings. The SA800 is the partnership’s own return; each partner’s personal tax position is reported separately on their SA100, with the SA104 pages added to show their share of the partnership’s profit or loss.

The two returns have different UTRs and can even have different deadlines in some circumstances, which is why it’s worth keeping the partnership’s paperwork and each partner’s personal paperwork clearly separated.