GP Locum Session Rate Calculator

It runs in both directions. Give it a session rate and it tells you what you actually keep; give it the take-home you need and it tells you the rate that produces it. The second is the one worth having when a practice asks what you charge, because “I need to clear £60,000” is a figure you know and a session rate is not.

It also prices the decision you make weekly: what one more session is worth after tax, National Insurance and pension. That number is a good deal smaller than the rate on the invoice.

• Gross to profit. Sessions times rate times weeks worked, less your expenses — either a single figure or itemised across indemnity, GMC, RCGP, accountancy and equipment — plus any mileage allowance.
• Pensionable pay is 90% of gross fees. The other 10% is treated as non-pensionable expenses, which is the standard locum treatment.
• The pension tier applies to all of your pensionable pay, not just the part above the boundary. Unlike an income tax band, crossing a tier re-rates the whole amount. That makes tier boundaries genuine cliff edges, and the tool warns when you are close to one.
• A locum with no other NHS pensionable work is assessed at the top 12.5% tier. This is deliberate, and explained below — it is the single biggest assumption in the tool.
• Then tax and NI. Income tax on profit after the pension contribution, with the personal allowance taper handled so the 60% effective band appears where it should, plus Class 4 National Insurance and any student loan repayment.
• The reverse solve is a search, not algebra. Because a tier re-rates the whole of pensionable pay, take-home does not rise smoothly with the rate — it dips slightly as you cross a boundary. A plain bisection assumes it never dips and can bracket the wrong side, so the solver scans across the range first to find a crossing and only then bisects inside it.

6 sessions a week at £350, 44 weeks a year — 264 sessions, £92,400 of fees — with £3,500 of expenses and the work pensioned. Every figure below is the calculator’s own:

• Pensionable pay of £83,160 at the 12.5% tier is £10,395 of pension, which buys about £1,540 a year of CARE pension for life.
• Income tax of £18,834 and National Insurance of £3,035. Set that against the invoice and it is £82.84 per session to hold back for tax.
• Take-home is £56,636 — £214.53 of the £350 you charged.
• One extra session grosses £350 and nets £179.38. The effective marginal rate is 48.8% — worth knowing before agreeing to cover an extra clinic.
• Run it backwards: to take home £60,000 on the same sessions and expenses, the rate needs to be £374.86 a session.

The gap between £350 and £374.86 a session — about £25 — is what £3,364 more in your pocket costs at the margin. If you would rather compare all this against a salaried post, the salaried vs locum calculator does it on a total-package basis.

Estimates on 2026/27 rates for England & Wales. Not tax or financial advice. The assumptions that matter:

• The top-tier pension assumption. NHSBSA annualises a locum’s pensionable pay over actual days of pensionable service, and for a locum with no other regular NHS work those days fall far short of a full year — every gap between bookings counts against it — which pushes the annualised figure into the top tier regardless of what was really earned. Rather than approximate the day-count, this tool assesses a sole locum at the top 12.5% tier outright. If you also hold a salaried or out-of-hours post, tell it so and the tier is looked up on your combined pensionable pay instead. The locum tax calculator shows the annualisation arithmetic itself, and the locum GP pension guide explains the mechanic.
• England & Wales income tax only. Scottish rates and bands are not applied here, so if you pay Scottish income tax the tax figures will be wrong.
• One trade, one year. No VAT, no limited company, no partnership share, no capital allowances beyond the expenses you enter.
• Cashflow is a sketch. Tick the first-year box and it adds the balancing payment and payments on account, but the dated timeline of when money actually leaves — and the setup checklist — live in the locum tax calculator.
• The annual allowance. A contribution of this size can bring the annual allowance into play, which is a separate calculation — see the annual allowance calculator.