Self Assessment. Done right.

You must file if you were self-employed earning over £1,000, a company director with untaxed income, a landlord with rental income above £1,000, or earned over £150,000 in employment income. You also need to file if you received over £10,000 in dividends or savings income, or if you or your partner earn over £60,000 and claim Child Benefit. If you're unsure, we'll check your position for free.

There's an automatic £100 penalty the day after the deadline, even if you owe no tax. After 3 months it becomes £10 per day for 90 days (up to £900), then a further £300 or 5% of tax owed at 6 and 12 months. Interest on unpaid tax runs at 7.75% from 1 February. We submit two weeks early so HMRC delays never become your problem.

Office costs, business travel and mileage (45p per mile for the first 10,000 miles), a proportion of home utilities if you work from home, phone and broadband, professional subscriptions, training in your existing trade, and equipment. The £1,000 trading allowance covers small earnings without receipts. We go through your bank statements line by line so nothing legitimate gets missed.

If your tax bill is over £1,000, HMRC requires two advance payments toward next year's tax — one on 31 January (alongside the balancing payment for the year you've just filed) and one on 31 July. Each is 50% of your previous year's bill. That's why your first January after a profitable year feels brutal. We forecast it months ahead so you can set the cash aside.

Self-Assessment is included in our Essentials plan from £99/month for sole traders, and in every Premium plan for directors. One-off Self-Assessment filing for non-clients starts at £150 for straightforward returns. Every return is reviewed by an ACCA-qualified accountant before submission, and we offer a 30-day money-back guarantee if you're not happy.