Methodology

How UKCalc calculates income tax, National Insurance, take-home pay and other UK financial figures for 2026/27.

Tax year: 2026/27 (6 April 2026 – 5 April 2027)  ·  Last updated: 26 May 2026. Report an error.

Income Tax — How We Calculate It

UK income tax is marginal — each rate applies only to the slice of income within that band, not to all income. Our calculators apply the following 2026/27 rates for England, Wales and Northern Ireland:

BandTaxable IncomeRateSource
Personal AllowanceUp to £12,5700%GOV.UK
Basic Rate£12,571 – £50,27020%GOV.UK
Higher Rate£50,271 – £125,14040%GOV.UK
Additional RateAbove £125,14045%GOV.UK

Personal Allowance Taper

For incomes above £100,000, the personal allowance is reduced by £1 for every £2 of income above £100,000. This creates an effective marginal rate of 60% on income between £100,000 and £125,140. At £125,140 the personal allowance is fully withdrawn.

Worked Example: £55,000 salary

Personal allowance (£12,570) → £0 tax

Basic rate band (£12,571–£50,270 = £37,700 × 20%) → £7,540

Higher rate slice (£50,271–£55,000 = £4,730 × 40%) → £1,892

Total income tax: £9,432/year

National Insurance — How We Calculate It

Employee National Insurance contributions (NICs) for 2026/27 are:

BandEarningsRateSource
Below Primary ThresholdUp to £12,570/year0%GOV.UK
Main Rate£12,570 – £50,270/year8%GOV.UK
Upper RateAbove £50,270/year2%GOV.UK

Worked Example: £50,000 salary

NI on £12,570–£50,000 = £37,430 × 8% → £2,994

Total employee NI: £2,994/year

Take-Home Pay — Calculation Order

We calculate take-home pay by applying deductions in this order:

  1. Salary sacrifice pension contributions are deducted from gross salary first, reducing the taxable base for both income tax and NI.
  2. Income tax is calculated on the adjusted gross salary (after salary sacrifice) using the PAYE bands above.
  3. Employee National Insurance is calculated on the adjusted gross salary.
  4. Student loan repayments are calculated after tax and NI, based on the plan-specific threshold applied to gross salary (not taxable pay).

Default assumptions: Standard 1257L tax code (full personal allowance of £12,570). No additional income sources. No benefits in kind. Single employer. The user can override these by adjusting the pension contribution field and student loan plan selector.

Student Loan Repayments

PlanThreshold (2026/27)RateSource
Plan 1£24,990/year9% above thresholdGOV.UK
Plan 2£27,295/year9% above thresholdGOV.UK
Plan 5£25,000/year9% above thresholdGOV.UK
Postgraduate Loan£21,000/year6% above thresholdGOV.UK

Salary Sacrifice Pension

Salary sacrifice pension contributions are deducted from gross salary before income tax and National Insurance are calculated. This means both taxes are reduced — unlike personal pension contributions (relief at source), which only save income tax.

Example: £35,000 salary, 5% salary sacrifice

Gross salary: £35,000

Salary sacrifice contribution (5%): £1,750

Adjusted taxable salary: £33,250

Income tax on £33,250: 20% × (£33,250 − £12,570) = 20% × £20,680 = £4,136

NI on £33,250: 8% × (£33,250 − £12,570) = 8% × £20,680 = £1,654

Monthly take-home: (£35,000 − £1,750 − £4,136 − £1,654) ÷ 12 = £2,288/month

Stamp Duty Land Tax (SDLT)

Our stamp duty calculator uses the 2026/27 SDLT rates for England and Northern Ireland:

Purchase PriceStandard RateFirst-Time Buyer Rate
Up to £250,0000%0% (up to £425,000)
£250,001 – £925,0005%5% (above £425,000)
£925,001 – £1,500,00010%10%
Above £1,500,00012%12%

Source: GOV.UK — Stamp Duty Land Tax. Our calculator assumes a standard residential purchase. Additional-rate surcharges (for second homes/buy-to-let) are not currently included — confirm with a conveyancer for non-standard purchases.

Mortgage Calculator

Our mortgage calculator uses the standard annuity repayment formula. For a mortgage of principal P, monthly interest rate r (annual rate ÷ 12), and n monthly payments:

Monthly payment = P × r × (1+r)^n / ((1+r)^n − 1)

Interest rates shown are illustrative. Actual mortgage rates depend on your lender, LTV, credit history and market conditions. We use Bank of England base rate publications as a reference for rate context.

Car Finance (HP and PCP)

Our car finance calculator uses the same annuity formula for Hire Purchase (HP) monthly payments, applied to the full vehicle price minus deposit. For Personal Contract Purchase (PCP), monthly payments are calculated on the amount financed between the purchase price and the Guaranteed Minimum Future Value (GMFV / balloon payment), using the same annuity formula.

Limitations of Our Calculations

What our calculators do not account for: Non-standard tax codes · Multiple employment income or self-employment · Benefits in kind (company cars, private medical insurance, etc.) · Scottish income tax (which has different rates and bands) · Marriage allowance transfers · Pension income alongside employment income · Blind Person's Allowance · Gift Aid adjustments to adjusted net income. If any of these apply to you, your actual tax will differ from our estimates.

Data Sources

National Insurance
Inheritance Tax

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