IT contractor on £143,000

Inside-IR35 Umbrella. Inside IR35. Age 40. Pension preference: aggressive.

Every figure on this page is computed at build time by the same engines that power the live salary–dividend split, take-home and SIPP optimiser calculators. Inputs come from a single CSV row; outputs come from the engines. No static lookup tables, no hand-coded numbers.

Net cash

£69,898

Pension

£21,450

Effective rate

36.1%

Marginal rate

42%

Worked example: IT contractor, 40, £143,000 of contract value

Picture a it contractor aged 40 for the 2026/27 tax year, on an inside-IR35 umbrella contract billing £650 per day for 220 days. The optimisation goal for this profile is maximum net wealth (treating £1 of pension as £1 of cash today).

Running the engine for this exact profile:

Day rate: £650 (220 billable days)
Contract value: £143,000
Net cash to the contractor: £69,898
Pension via salary sacrifice: £21,450
Total deductions through the chain: £51,652 (36.1% effective on contract value)
Break-even outside-IR35 day rate: £724/day

The vignette is hypothetical but the numbers are not — every figure above was produced by the same engine code that powers the live BracketMath calculators, run at build time on inputs drawn from a single CSV row.

The numbers, line by line

Day rate	£650
Contract value (220 days)	£143,000
Inside-IR35 net cash	£69,898
Inside-IR35 pension	£21,450
Outside-IR35 net cash	£75,551
Outside-IR35 pension	£21,000
Cost of being inside IR35 (net wealth)	£5,204
Break-even outside-IR35 day rate	£724

Why this scenario is different

Compared to the closest peer profile — Project manager contractor at £143,000 — this scenario sits £0 higher on gross income. That moves net cash by +£0, the pension contribution by +£0, and the effective rate by +0%. The effective rate moves only modestly — both scenarios sit inside the same binding tax band. The break-even outside-IR35 day rate moves from £724 to £724 per day.

Questions this scenario raises

How much can I put into pension this year?

The 2026/27 pension Annual Allowance is £60,000. Below £260,000 of adjusted income the full £60,000 Annual Allowance is available. Carry-forward of unused AA from the last three tax years is available subject to membership-in-each-year rules.

Is the Apprenticeship Levy actually due on my umbrella rate?

Legally, only if the umbrella's total annual paybill exceeds £3 million — and even then it falls on the umbrella, not the contractor. In practice many umbrellas pass it through as a 0.5% deduction. This page models the levy as off by default; toggle it on in the take-home calculator to see the effect.

Why does the take-home calculator default to 220 billable days?

220 is the conservative consultancy assumption for a working year after holiday (typically 25–28 days), bank holidays (8–9 days), illness (3–5 days) and unbillable time (training, business development, gaps between contracts). Many calculators use 230 or 240; we lean conservative because the gap between billable expectation and reality is a common contractor planning error.

Is salary sacrifice into a pension worth it inside IR35?

Yes — by a wide margin. Salary sacrifice removes the pension contribution from the gross before the employer-NI / employee-NI / income-tax stack is applied. Each £1 sacrificed costs the contractor roughly 50–70p of cash today (depending on tax band) and lands £1 in the pension. There is no other comparable lever inside IR35.

What is the cost of being inside IR35 vs outside at this day rate?

For this row, operating inside IR35 instead of outside costs £5,204 per year of net wealth (cash + pension). To match the outside-IR35 take-home at the same day rate, an inside contract would need to be priced at approximately £724/day.

Methodology

Income tax, National Insurance and Corporation Tax bands taken from HMRC's 2026/27 rates and allowances tables (gov.uk/.../income-tax; corporation-tax). Pension Annual Allowance and taper rules from Finance Act 2004 / 2023. Trading allowance per ITTOIA 2005 s.783A. Voluntary Class 2 figure (£179.40/yr = £3.45/wk × 52) from HMRC voluntary NI guidance.

Style: 2026/27 tax year throughout; figures rounded to whole pounds in the user-facing prose; effective rates computed as (deductions / gross). The voice is methodological — no first person, no claimed credentials, no marketing fluff.

This page is not personalised advice; for advice regulated by the FCA, consult an adviser registered with the Financial Conduct Authority. See the full disclaimer.