Self Assessment settings

Go to Settings, then Self Assessment Settings.

These are answers about the trade itself. Between them they decide how the profit on your Self Assessment is worked out, so each card tells you what the setting is doing to your figures right now.

Anyone from the Tax, Accounting & Users level up can read the page; saving needs write access as well, so a read-only accountant sees the settings without being able to change them. The page does not apply to a limited company and says so instead of erroring.

Whose trade it is

The proprietor is the person whose Self Assessment these profits go on.

A sole trader has exactly one owner, and that owner is the proprietor by definition - so Kontala states the name rather than offering a choice. To change it, change who owns the business on the Users screen.

Two things follow from being the proprietor:

• Their Self Assessment covers the profits of all their businesses together.
• They can never be paid through payroll. Money they take out of the business is drawings, not salary.

Accounting basis

This is the basis your trading profit is worked out on:

• Cash basis - income counted when you are paid, costs when you pay them. The default for sole traders and partnerships since 2024/25.
• Traditional (accruals) basis - income when you invoice it, costs when you incur them, with closing stock valued and carried.

Leave the picker empty to use the default for your business type. When the cash basis is in force, the card names the actual adjustment it is causing on your Computation tab and for which year, so you can go and check it.

This is not the same as your VAT accounting basis, which is set under VAT Registration. The two are independent, and you can be on one and not the other.

What the cash basis does to stock

On the cash basis, stock is deducted when you pay for it, so there is no closing valuation to carry - and inventory tracking is switched off.

Your Products & Services catalogue still pre-fills invoices and bills as normal. Only quantity and value tracking is unavailable.

Simplified expenses

HMRC's three flat rates, for sole traders and partnerships. Each is an independent choice - you can use one and not the others:

• Flat-rate mileage instead of actual vehicle costs. 45p a mile to 10,000 miles, then 25p. While this is on, your actual running costs are excluded from box 20.
• Flat-rate use of home, by hours worked each month. £10 to £26 a month depending on hours, instead of apportioning your household bills.
• Flat-rate adjustment for living at your business premises. For a pub or guest house where the family lives on site.

Accounting date

This card appears only if your accounting year end falls between 31 March and 4 April. Most businesses never see it.

By default HMRC treats a year end in that window as ending on 5 April, so your profits fall in a single tax year with no split and no provisional figure.

Tick Apportion my profits strictly across tax years only if you have elected to. Doing so splits each set of accounts by days across the two tax years it falls in, which makes the current year provisional until the later accounts are made up - and blocks closing it.

Why CIS is not on this page

If you work under the Construction Industry Scheme, that lives on its own screen. A contractor or subcontractor can be any legal form, including a limited company, while this whole page answers "not applicable" to one.

See CIS.

Related

• The cash basis and the accruals basis
• Your accounting date and the tax year
• Accounting dates and settings