What Inside IR35 Costs at £1050/Day
£1050/day across 220 working days is £231,000 a year. Inside IR35 that whole amount is taxed like a salary (typically via an umbrella company): at 2025/26 rates (thresholds frozen to 2028) you pay £90,153 income tax and £6,631 employee National Insurance, keeping £134,216 — 58.1% of gross. Outside IR35, running the same contract through your own limited company with an optimised salary-plus-dividends structure typically retains around 78% — about £180,180 a year. The gap of roughly £45,964 works out at £209 for every day you work. Run your own split in the IR35 calculator.
The Maths Behind the Numbers
At £231,000 — about 6.6 times the UK median full-time salary of roughly £35,000 — every marginal pound inside IR35 loses 47p (45% additional-rate tax plus 2% NI). The personal allowance was fully withdrawn back at £125,140, so the 60%+ marginal zone between £100,000 and £125,140 is already priced into the figures above. That is why the inside-IR35 effective deduction rate reaches 41.9% here, and why status determinations matter so much more at £1050/day than at £500/day.
Can You Improve Either Position?
Pension contributions are the single most effective tax lever at this income, with relief at your 47% marginal rate. The standard annual allowance for 2025/26 is £60,000, and under HMRC's rules (gov.uk guidance on the tapered annual allowance) the taper only begins once adjusted income exceeds £260,000. At £231,000 you are close to that line — adjusted income includes employer pension contributions, so a large contribution can itself trigger the taper, which removes £1 of allowance for every £2 above £260,000 down to a £10,000 floor. If you work outside IR35, employer contributions made directly from your limited company are corporation-tax deductible and never touch the dividend chain, which makes them doubly efficient — but they still count towards adjusted income for the taper. Inside IR35, some umbrella companies offer salary sacrifice into a pension, which restores relief at the full marginal rate — worth asking before you sign. Read our complete contractor IR35 guide for how status is assessed, and the high-earner tax tips and £100k tax trap guides for the wider planning picture.
Day Rates Compared
| Day Rate | Outside IR35/mo | Inside IR35/mo | Annual Loss |
|---|---|---|---|
| £750/day | ~£10,725 | £8,270 | £29,464 |
| £800/day | ~£11,440 | £8,756 | £32,214 |
| £900/day | ~£12,870 | £9,727 | £37,714 |
| £1000/day | ~£14,300 | £10,699 | £43,214 |
| £1050/day | ~£15,015 | £11,185 | £45,964 |
| £1100/day | ~£15,730 | £11,671 | £48,714 |
| £1150/day | ~£16,445 | £12,156 | £51,464 |
| £1200/day | ~£17,160 | £12,642 | £54,214 |
| £1250/day | ~£17,875 | £13,128 | £56,964 |
See also the £1050 day rate take-home breakdown, the £1050/day permanent salary equivalent, or browse all IR35 rate comparisons.
FAQs
How much does inside IR35 cost on £1050/day?
Roughly £45,964 a year. Inside IR35 you take home about £134,216 (£11,185/month), while outside IR35 through a limited company you could keep around £180,180 (~£15,015/month) at a typical ~78% retention.
What is the take home for £1050/day inside IR35?
£11,185/month. £1050/day across 220 days is £231,000 gross; income tax of £90,153 and National Insurance of £6,631 at 2025/26 rates (thresholds frozen to 2028) leave £134,216/year.
Why is the outside IR35 figure an estimate?
The ~£15,015/month figure assumes roughly 78% retention through an optimised salary-plus-dividends structure. Actual retention depends on your salary/dividend split, corporation tax, allowable expenses and how much profit you retain in the company.