PayMetric Labs
2026/27 UK IR35 · Inside vs Outside comparison

Site Reliability Engineer Day Rate Calculator: UK 2026/27

Pre-filled with the £625/day Site Reliability Engineer benchmark rate in United Kingdom. Adjust to your actual rate for a precise take-home figure.

IR35 take-home calculator

Pre-filled with the Site Reliability Engineer median £625/day benchmark. Adjust for your actual rate.

Your contract details

£

230 days = 46 weeks billed, allowing for holiday and downtime

£

Equipment, software, training, travel. £1,500 accountancy already included.

%

Company pension (outside) or salary sacrifice (inside). Reduces taxable income.

Common day rates:

OUTSIDE IR35

Limited company

£87,116

Effective tax rate: 39.4%

INSIDE IR35

Umbrella company

£76,540

Effective tax rate: 46.8%

Being outside IR35 puts £10,576 more in your pocket per year (13.8% more than inside IR35)

Contract revenue: £143,750 · Working days: 230 · Day rate: £625

Calculations use 2026/27 UK tax rates. Outside IR35 assumes optimal salary/dividend structure with a fixed director salary of £12,570, employer NI at 15% above the £5,000 secondary threshold, and £1,500 accountancy fees. Inside IR35 assumes a compliant umbrella company deducting employer NI before deemed salary. Pension contributions are assumed to be company contributions (outside) or salary sacrifice (inside). Figures are estimates only. Consult a qualified contractor accountant before making decisions.

Frequently asked questions

1

What is IR35 and does it affect Site Reliability Engineer contractors?

IR35 is HMRC's off-payroll working legislation. If your engagement is deemed "inside IR35," you are taxed as an employee (Income Tax and National Insurance on your full contract rate), even if you operate through a limited company. Outside IR35 you can pay yourself a mix of salary and dividends through your limited company, retaining more of your income. Site Reliability Engineer contractors typically work on project-based engagements, which may qualify as outside IR35 if the contract and working practices confirm genuine business-to-business arrangements.

2

How much more do Site Reliability Engineer contractors earn outside IR35?

The difference depends on day rate and working days. At a typical mid-market rate the outside IR35 advantage is often £8,000–£20,000/year after all taxes and costs. The calculator above shows an exact comparison for the Site Reliability Engineer benchmark rate.

3

How are Site Reliability Engineer contractor rates determined in the UK?

Contract rates reflect supply and demand in the freelance and contract market, adjusted for specialisation, seniority, and location. Site Reliability Engineer rates have historically commanded a premium over equivalent permanent-salary daily equivalents to account for the absence of benefits, pension contributions, and employment security. The benchmark on this page is derived from published UK contract market data.

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