Why your day rate is not your wageA £300 day rate does not mean £300 in your pocket. Before you see any of it, that money has to cover:Business costs: van finance, fuel, insurance, tools, phone, accountant, software, certification, waste disposal.Income Tax and Class 4 National Insurance on what is left.The days you are not on site: holidays, bank holidays, illness, and every hour spent quoting, chasing invoices and buying materials.Work through the figures above and you can see how costs and fewer chargeable days raise the rate you need. Working four days a week does not reduce annual business costs by a fifth, so the day rate has to rise.The days you can actually charge forThere are 260 weekdays in a year. Almost nobody bills 260. Using the default example, take four weeks off, the eight bank holidays and five days of illness, and you are at 227. Take off half a day a week for quoting, paperwork and merchant runs, and you are at roughly 203 chargeable days. That is the number your rate has to be built on, based on the default entries above.If you plan around more days than you can actually invoice, the shortfall has to be recovered in the day rate.How much you need to chargeThe calculator works it out in four steps:Start with your take-home target. Not turnover. The money you want in your account.Gross it up through tax. On the 2026/27 basis that means a £12,570 Personal Allowance, Income Tax at 20% up to £50,270 and 40% above, and Class 4 National Insurance at 6% between £12,570 and £50,270 then 2%.Add your business costs. These come out of turnover, so they have to be earned on top.Divide by your chargeable days. Use chargeable days, not every weekday.The result is an estimated starting rate based on the figures you entered. Add a margin for unexpected costs and jobs that take longer than planned.Charging by the hour insteadThe calculator shows an hourly equivalent on an eight-hour day. Two things to watch: Hourly pricing can underprice experience. Get faster and you earn less for the same job. If you are experienced, price by the job or the day.Minimum call-out charges exist for a reason. A twenty-minute job that takes forty minutes of driving is not a twenty-minute job.What the day rate does not coverThree things sit outside the calculation and all three catch people out.Payments on account. In your first year of self-employment, the bill due on 31 January is not just last year’s tax. HMRC also asks for half of next year’s up front, and another half on 31 July. On £49,945 of profit that turns a £9,718 tax bill into roughly £14,576 in January and £4,859 in July. The calculator flags this once your tax bill goes over £1,000, although payments on account are not normally required if more than 80% of the tax due was collected outside Self Assessment. Budget separately for this cash-flow timing.Student loan. Repaid through Self Assessment, on top of Income Tax and National Insurance. Plan 2 takes 9% of everything above £29,385; Plan 1 above £26,065; Plan 5 above £25,000; postgraduate loans another 6% above £21,000, and they stack. On £49,945 of profit a Plan 2 borrower repays about £1,850 a year. Set the plan in the calculator and it is built into your rate.Pension. A personal pension contribution is not a business expense. It does not reduce your trading profit, and it never reduces Class 4 National Insurance. Basic-rate relief is normally added by the provider, while any further relief depends on your tax position. So pension money comes out of your take-home, which is why the calculator asks you to include it in your target rather than entering it separately.Common questionsWhat is a good day rate for a UK tradesperson?It depends far more on your costs and your chargeable days than on your trade. Rather than copy someone else’s number, put your own costs and days into the calculator. Two electricians in the same town can need different rates because their costs and chargeable days differ.Should I charge VAT on top of my day rate?Charge VAT only if you are VAT registered and the VAT rules require it for that supply. You may need to register when your VAT-taxable turnover exceeds £90,000 under either of HMRC’s registration tests.How do I put my rate up with existing customers?Give customers reasonable notice, explain the new rate clearly and confirm when it starts. Keep the wording factual and apply the change consistently.Should I include a pension?Yes, if you can. There is no employer paying into one for you. Put the figure into the calculator and it will be built into the rate rather than being something you find money for at the end of the year.Does this cover Scotland?Not yet. Scotland sets its own Income Tax bands, so the tax figures here apply to England, Wales and Northern Ireland.Related guidesHow much should you charge? Day rates and pricing for UK tradesHow to price a job and make a profitHow much should you set aside for tax as a sole trader?Written by Chris, founder of TradePilot. Last reviewed 10 September 2026. Figures on this page use the 2026/27 tax year for England, Wales and Northern Ireland. This is general information, not tax advice.