A partnership is a straightforward structure for two or more people going into business together, but it involves joint legal liability and shared Self Assessment obligations. Understanding how partnership tax works — and where it differs from running parallel sole trader businesses — helps you make an informed decision about how to structure a joint venture.
Written and reviewed by James Whitfield · Updated August 2026 · Checked against 2026/27 HMRC rates · Editorial standards · Methodology
A partnership is not taxed as a separate entity — it files one partnership return (SA800), then each partner pays Income Tax and Class 4 NI on their share through their own Self Assessment.2 The tax advantage over one person trading alone is income splitting: two partners each get their own £12,570 Personal Allowance and basic-rate band, so profit that would hit 40% in one person's hands can stay at 20%. On £80,000 split equally, a partnership pays about £8,025 less than a sole trader on the full £80,000. The trade-off is joint and several liability — each partner is personally liable for the whole partnership's debts.
A partnership exists when two or more people carry on a business in common with a view to profit. There is no formal registration required to form a partnership — it can come into existence informally when partners start trading together, though a formal partnership agreement is strongly advisable.
Partnerships make sense when multiple people are genuinely sharing the running of a business — where the contribution is collaborative and the profit genuinely shared rather than one person paying another for services. Freelancers who occasionally collaborate on projects do not necessarily form a partnership; a husband and wife running a guest house together probably do.
The main practical advantage of a partnership over two separate sole trader businesses is that profits can be allocated in any agreed ratio, which allows income to be managed across partners with different tax positions. The main disadvantage is joint and several liability — in a general partnership, each partner is personally liable for the debts of the whole partnership, not just their own share.
A partnership is not itself a taxable entity. Instead, it files a partnership return (SA800) each year showing the partnership's total income, expenses and profit. The profit is then allocated to each partner according to the partnership agreement, and each partner pays income tax and Class 4 NI on their own share through their individual Self Assessment return.
One partner must be nominated as the designated partner (or 'nominated partner') for filing purposes. This person is responsible for filing the SA800 partnership return by 31 January each year and for ensuring the partnership's records are maintained. Each partner then independently files their own SA100 showing their allocated share of the partnership profit alongside any other income.
The allocated share is taxed as self-employment income in each partner's hands. Income tax applies at the partner's personal marginal rate; Class 4 NI at 6% up to £50,270 and 2% above applies to each partner's share. Each partner has their own personal allowance, which is not pooled — a partner who has allocated profit below their personal allowance pays no income tax on that share.
Take a business generating £80,000 of annual profit. Split equally between two partners, each is taxed on £40,000 — comfortably inside the basic-rate band. Earned by one person as a sole trader, the same £80,000 pushes a large slice into the 40% band. The gap is the whole point of the structure.
| Total business profit | £80,000 |
| Partner A share (£40,000) — Income Tax + Class 4 NI | £7,132 |
| Partner B share (£40,000) — Income Tax + Class 4 NI | £7,132 |
| Partnership — combined tax and NI | £14,264 |
| Same £80,000 as one sole trader — tax and NI | £22,289 |
This only works where both partners genuinely work in the business and the profit split reflects that. HMRC can challenge an allocation that shovels profit to a lower-earning spouse purely to save tax with no commercial basis. Get the split right — and documented in a partnership agreement — and the saving is legitimate.
As profits grow above £60,000–£80,000 combined, a limited company often becomes worth considering. The company pays corporation tax on profits (currently up to 25% on profits above £250,000, but lower on smaller profits), and the partners-turned-directors extract income as a combination of salary and dividends. Dividend tax rates (10.75% basic rate, 35.75% higher rate for 2026/27) are lower than income tax rates on the equivalent income.
The additional administration of a limited company — annual accounts, corporation tax return, confirmation statement, payroll, dividend paperwork — costs roughly £1,000–£2,000 more per year in accountancy fees than a partnership of comparable size. This cost needs to be factored against the tax saving.
One partnership-specific consideration is limited liability partnerships (LLPs). An LLP combines the flexibility of a partnership with limited personal liability for partners in respect of the LLP's debts, while maintaining pass-through taxation rather than corporation tax. LLPs are more commonly used by professional services firms than small trades businesses, but they are worth knowing about if liability protection is a concern.
There is no requirement to register a general partnership at Companies House. However, an LLP (limited liability partnership) must be registered. All partnerships must register with HMRC and file an annual partnership return (SA800).
Yes, provided both genuinely work in the business. HMRC scrutinises arrangements where profit is allocated to a lower-earning spouse primarily for tax reasons without genuine commercial justification. The allocation should reflect the commercial reality of each partner's contribution.
The nominated partner is responsible for filing the partnership's SA800 tax return. Any partner can be nominated. The nominated partner must be registered as such with HMRC.
The partnership dissolves or is reconstituted depending on the partnership agreement. Tax adjustments may be required for the year of change. A good partnership agreement will define the process for a partner exiting.
In terms of personal liability, a general partnership is arguably riskier because each partner is jointly and severally liable for the partnership's debts — including debts incurred by the other partners. An LLP removes this risk but involves more administration.
The rates, thresholds and rules in this guide are drawn from the official HMRC and GOV.UK sources below, using the confirmed 2026/27 figures. Each link opens the relevant official page in a new tab.
The sole trader tax calculator turns this guidance into a concrete monthly take-home and tax reserve estimate, based on 2026/27 HMRC rates. Enter taxable profit — not turnover.
Self Assessment checklist, expense tracker and payments on account calendar — all in one practical PDF. Updated for 2026/27.
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