Keeping your business expenses HMRC-ready in 15 minutes a week

2026/27 simplified mileage rate: For self-employed simplified expenses, HMRC's rate for cars and goods vehicles is 55p per business mile for the first 10,000 miles and 25p per business mile after that. The 55p rate applies retrospectively from 6 April 2026. Check GOV.UK simplified vehicle expenses before relying on the figures.

The single biggest source of January misery for UK sole traders is reconstructing twelve months of business expenses from a drawer of receipts, a fragmented bank statement, and memory. Almost everyone says they'll do it differently next year. Almost nobody actually does.

It isn't laziness — nobody has shown them what "doing it differently" actually looks like in practice. The honest answer is fifteen minutes a week. That's it. The rest of this post explains exactly what those fifteen minutes consist of and why this small habit prevents the January problem entirely.

For self-employed people, every legitimate business expense you fail to claim is tax you didn't owe but paid anyway. Over a year that typically adds up to several hundred pounds, sometimes more. The expenses that get missed aren't the obvious ones (you remember the £400 laptop you bought in March) — they're the small recurring ones: the £15 phone bill, the £8 cloud storage subscription, the £25 fuel top-up on a job last Tuesday. Individually small, collectively meaningful.

When MTD for Income Tax applies, keep digital records and use compatible software to send cumulative quarterly updates for each business. Quarterly updates are summaries, not tax returns; the required tax return and finalisation obligations still apply. Check current GOV.UK guidance for your start date and workflow.

You need three things, all of which can live in a single spreadsheet or in basic accounting software.

A list of expense categories tailored to your business. Not generic ones. The specific cost types you actually incur. For a plumber that's pipe fittings, boiler parts, van fuel, tool replacement, trade insurance. For a beauty salon owner that's products, disposables, salon rent, insurance, training. For a freelance designer that's software subscriptions, hardware, professional memberships, training, home office costs. The categories matter because consistency over a year is what makes the records useful.

A way to capture receipts. The cleanest is a dedicated email folder ("Business receipts") that you forward every receipt into the moment you receive it. For paper receipts, photograph them with a basic receipt app or your phone's notes, and store them in a labelled folder per quarter. The point is that a receipt has a known location and you can find it again.

A simple log. Date, supplier, category, amount, payment method, receipt reference (where the proof lives). One row per expense. That's it.

If your business has a separate bank account (and it should), most of your expense entries can be picked off the bank statement. The category and the receipt reference are the parts that need your attention.

Once a week, ideally at the same time. Friday afternoons work for most self-employed people because it closes off the working week. Sunday evenings work for the people who'd rather not have admin hanging over the weekend.

Step one (five minutes): pull up your business bank account. Look at every transaction since your last admin slot. Most weeks this is somewhere between five and twenty transactions.

Step two (eight minutes): for each business transaction, log it in your spreadsheet or accounting tool. Date, category, amount, payment method. If a receipt exists, note where it lives (email folder, photographed, supplier portal). If a transaction is personal that ended up on the business account by mistake, mark it personal so it gets excluded from your tax return.

Step three (two minutes): glance through your business email folder for any receipts that arrived but didn't trigger a bank transaction (subscription renewals paid by direct debit you forgot about, monthly software invoices). Make sure each one is logged.

That's the whole routine. Done weekly, it produces a complete, structured set of expense records over a year. It also gives you something most sole traders never have: an accurate sense of where your money is actually going from month to month.

For self-employed home working, HMRC's simplified-expenses rates are £10 per month for 25–50 business hours, £18 for 51–100 hours and £26 for 101 hours or more. Telephone and internet are handled separately using the actual business proportion. For cars and goods vehicles in 2026/27, the simplified mileage rate is 55p for the first 10,000 business miles and 25p thereafter. Check eligibility and retain adequate records.

Training, bank charges, telephone and broadband may be relevant business costs, but eligibility and the business proportion depend on the facts. Do not use a generic percentage as proof. Check the current rules and retain records that support the amount claimed.

A common misconception is that paying for an accountant means you don't need to track expenses yourself. Your accountant can only work with the records you give them — give them a shoebox and they spend their time sorting it (and bill you for it). Clean records typically save £200–£500 per year on accountant fees. Beyond the bill, the bigger gap is real-time visibility: without your own running records you cannot make pricing or cash-flow decisions on data your accountant will surface in three months' time. The right model is that you track expenses weekly and your accountant does the tax work using your structured records.

Most sole traders know fifteen minutes a week would solve the problem. Almost nobody does it, because the routine has no immediate payoff. The benefit is invisible until tax season twelve months later, by which point the connection between the weekly habit and the smooth tax submission is easy to miss. The trick is to anchor the routine to something visible: same time every week, calendar reminder, paired with something you already do (the Friday wind-down works for most). The habit sticks within a month. By the following January, you skip the reconstruction weekend entirely, which is when the small weekly cost pays for itself many times over.

LaunchKit Financial Forms are available for the business types listed in the live catalogue. Each niche page shows its exact distinct-form count and included-document list. Standard is £11.99, Custom is £13.99 and Premium is £19.99; the live page states the verified formats and editing scope.

If you'd rather build your own spreadsheet with the categories that fit your business, the structure above gives you the template. The bundle just saves the setup time.

This article is general guidance, not tax advice. For your specific tax position, consult a qualified accountant.

For accountants and bookkeepers, this is also the habit your own practice needs before client work takes over the week.

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• Accountant / Bookkeeper financial forms bundle