UK Contractor & IR35 Calculators
A central hub of free, HMRC-aligned tools for UK contractors. Compare inside vs outside IR35, model umbrella vs limited company take-home, price new day rates and project the dividend tax on a tax-efficient salary + dividend split — all built around the 2025/26 UK tax year.
UK contractor taxation in 2025/26
Three ways to be paid as a UK contractor — and three very different tax bills
Most UK contractors are paid through one of three structures: agency PAYE, an umbrella company, or their own limited company. Which one applies depends on your IR35 status, the end client's size, and how comfortable you are running a small business. The take-home difference between these routes on a typical £500 day rate can easily exceed £15,000 a year.
IR35 (the off-payroll working rules) is the rule that decides whether your engagement is genuine self-employment or disguised employment. Inside IR35 income is taxed via PAYE Income Tax and National Insurance with no salary/dividend split. Outside IR35 income flows through your limited company, where corporation tax (19–25%), the £500 dividend allowance and dividend tax rates of 8.75 / 33.75 / 39.35% all come into play.
The calculators below model these flows using current HMRC thresholds: the £12,570 personal allowance, 20 / 40 / 45% Income Tax bands, employee NI at 8% and 2%, employer NI at 15% above £5,000, the apprenticeship levy of 0.5% on umbrella assignments, and the standard salary + dividend mix for director-shareholders. Use them to compare offers, plan drawings, or decide between umbrella and limited company contracting.
The calculators
Seven contractor tools covering IR35 status, umbrella vs limited company take-home, day rate pricing and dividend tax planning.
IR35 Comparison Calculator
Compare inside IR35, outside IR35 and umbrella take-home side by side on the same day rate.
Best for: Contractors weighing up status & structure
Open calculatorContractor Calculator (Outside IR35)
Model a tax-efficient salary + dividend split through your limited company, with corporation tax and dividend tax included.
Best for: Outside IR35 limited company contractors
Open calculatorInside IR35 Calculator
Estimate take-home pay when your engagement is caught by the off-payroll working rules and taxed via PAYE.
Best for: Public sector & medium/large private contracts
Open calculatorUmbrella Company Calculator
See net pay after employer NI, the apprenticeship levy, umbrella margin, PAYE and pension contributions.
Best for: Umbrella employees on PAYE assignments
Open calculatorContractor Take-Home Pay
UK PAYE take-home calculator covering Income Tax, National Insurance, pension and student loan deductions.
Best for: Benchmarking permanent vs contract offers
Open calculatorDay Rate Calculator
Convert annual salary into an equivalent contractor day rate (or vice versa) with realistic billable-day assumptions.
Best for: Pricing new contracts & negotiating rates
Open calculatorDividend Tax Calculator
Built into the Contractor Calculator — model salary + dividends with the £500 dividend allowance and 8.75 / 33.75 / 39.35% rates.
Best for: Limited company directors planning drawings
Open calculatorHMRC-aligned
Built around the 2025/26 personal allowance, Income Tax bands, NI rates and dividend thresholds.
Transparent assumptions
Every calculator shows the inputs and methodology — no black boxes, no email gates.
Always free
Educational tools for UK contractors. For complex decisions, speak to a qualified UK accountant.
Read up before you decide
Plain-English UK contracting guides covering IR35 status, umbrella deductions and limited company structuring.
FAQs
UK contractor & IR35 questions
Not sure where to start? Compare IR35 status first.
The IR35 Comparison Calculator shows umbrella, inside IR35 and outside IR35 take-home for the same day rate — the fastest way to understand what your engagement is actually worth.