How to set your freelance day rate in the UK (with actual maths)

Most new UK freelancers set their day rate the same way: take the salary they used to earn, divide by 260 working days, add a bit. Six months later they're working more than they did as an employee and taking home less. The maths is wrong in three places.

The three errors in "salary ÷ 260"

Error 1: you won't bill 260 days. Between holidays (25+ days if you want an employee-equivalent life), bank holidays, sales calls, proposals, admin, invoicing, gaps between contracts, and the occasional sick day, most freelancers bill 150–200 days a year. Contract developers on long engagements sit at the top of that range; project-based designers and writers at the bottom.

Error 2: employees don't pay business costs. Your laptop, software subscriptions, insurance (professional indemnity is often contractually required), accountant, co-working space, and training all come out of your rate now. For a typical solo developer that's £2,000–£4,000 a year before anything exotic.

Error 3: turnover isn't take-home. As a sole trader you'll pay income tax and National Insurance on profits through self-assessment. A common planning habit is setting aside 25% of everything you invoice into a separate account. Your real effective rate might be lower (personal allowance) or higher (higher-rate band) — but 25% is a buffer that rarely leaves you short at the January payment deadline.

The formula

gross needed = (target take-home + annual expenses) / (1 − tax set-aside)
day rate     = gross needed / realistic billable days

Worked example — you want £40,000 take-home, expect 170 billable days, spend £2,500 on the business, and set aside 25%:

gross needed = (40,000 + 2,500) / 0.75 = £56,667
day rate     = 56,667 / 170        = £333/day

Not the £154/day that "£40k ÷ 260" suggests. That gap is why freelancers who price from the naive formula burn out.

We built a free day-rate calculator that runs this exact formula — change the billable-days assumption and watch how violently the rate moves. That sensitivity is the real lesson: protecting billable days is worth more than small rate increases.

Sanity-check against the market

The formula gives you your floor. The market sets your ceiling. Check both:

• Contract job boards show day-rate ranges for your stack and seniority — if your floor is above the market ceiling, the answer is repositioning (different clients, different offer), not quietly accepting less.
• If your floor is well below market, charge market anyway. Pricing at your personal floor just donates the difference to clients.

One admin note

If you're earning more than £1,000 a year from self-employment, you need to register for self-assessment with HMRC — the £1,000 trading allowance covers genuine micro side-income only. Track everything from day one; a spreadsheet is fine at the start (we're releasing a purpose-built UK freelancer finance spreadsheet that does the tax set-aside automatically).

This is general information, not tax advice — for anything non-trivial, an hour with an accountant pays for itself.