Reference guide

Calculator help

This page documents every input, output, rule, threshold, and assumption used by the calculator. The tables below use the same tax-year assumptions as the calculator.

Inputs

Input What it means How it affects the result
Gross annual salary Your annual employment pay before income tax, employee National Insurance, pension, and loan deductions. Used as the starting point for income tax, NI, student loans, postgraduate loans, and pension calculations.
Tax year The UK tax year used for the estimate. The current default is 2026/27. Selects the allowances, tax bands, NI thresholds, student loan thresholds, and pension qualifying earnings limits.
Tax code Your PAYE tax code, such as 1257L, S1257L, C1257L, 0T, BR, D0, D1, NT, or K475. Changes the personal allowance or tax treatment used for income tax. Prefix S applies Scottish bands; prefix C is treated as Welsh/England-style bands in this calculator.
Tax region England, Wales or Northern Ireland; or Scotland. Changes income tax bands only. Employee NI and student loan calculations use the same thresholds regardless of region.
Pension method How your employee pension contribution is treated for tax and NI. Net pay and salary sacrifice reduce taxable pay. Salary sacrifice also reduces pay for NI. Relief at source applies basic-rate relief after tax is calculated.
Employee pension The employee pension contribution as a percentage of pensionable pay. Deducted from take-home pay. The pension method determines whether it also reduces taxable pay or NI pay.
Use qualifying earnings Uses auto-enrolment qualifying earnings rather than full salary for pensionable pay. The calculator applies the lower and upper qualifying earnings limits for the selected tax year.
Monthly salary sacrifice A monthly pre-tax sacrifice amount for schemes such as an EV or car salary sacrifice arrangement. Annualised and deducted from pay before income tax, employee NI, student loan, and postgraduate loan calculations. It is also shown as a deduction from bank pay.
Annual bonus No bonus, a fixed annual bonus amount, or a maximum bonus percentage of base salary. Included in total gross income for income tax, employee NI, student loan, and postgraduate loan estimates. Pension is calculated from base salary.
Student loan None, Plan 1, Plan 2, Plan 4, or Plan 5. When selected, repayments are calculated as 9% of gross salary above the plan threshold.
Postgraduate loan Whether to include a UK postgraduate loan deduction. When selected, repayments are calculated as 6% of gross salary above the postgraduate threshold.

Outputs

Estimated take-home

Gross salary minus income tax, employee NI, employee pension, student loan, and postgraduate loan deductions.

Monthly and weekly pay

Annual take-home divided by 12 or 52. The calculator does not model payroll-period rounding.

Taxable pay

Pay after personal allowance and any pension treatment that reduces taxable pay.

Effective deduction rate

Total deductions divided by gross salary.

Income Tax

The calculator starts with pay for tax, applies the personal allowance from the tax code, then applies the tax bands for the selected region. The personal allowance is reduced by 50% of income above £100,000, which means £1 of allowance is removed for every £2 above that point.

Taxable pay is never allowed to go below zero. If the personal allowance is larger than pay for tax, income tax is zero.
Supported tax code patterns
Code How it is estimated
1257L or similar The number is multiplied by 10 to set the annual personal allowance. 1257L gives a £12,570 allowance.
S prefix Uses Scottish income tax bands, for example S1257L.
C prefix Accepted for Welsh tax codes. Current bands match England and Northern Ireland in this calculator.
0T No personal allowance is applied, but normal tax bands are still used.
BR, D0, D1 All taxable pay is taxed at 20%, 40%, or 45% respectively.
NT No income tax is deducted.
K codes The code number is treated as a negative allowance, increasing taxable pay. For example K475 adds £4,750 to taxable pay.

National Insurance

Employee National Insurance is calculated using the annual primary threshold, upper earnings limit, main rate, and additional rate for the selected tax year. Salary sacrifice pension contributions reduce pay for NI; other pension methods do not.

Boundary Meaning Current value
Primary threshold Employee NI starts above this annual level. £12,570
Upper earnings limit Main employee NI rate stops and additional rate starts above this level. £50,270
Main employee rate Rate between the primary threshold and upper earnings limit. 8%
Additional employee rate Rate above the upper earnings limit. 2%

Student and Postgraduate Loans

Student loans are calculated as 9% of gross salary above the selected plan threshold. Postgraduate loans are calculated as 6% of gross salary above £21,000. If both apply, both deductions are included.

Pensions

None

No pension contribution is deducted and taxable pay is unchanged.

Net pay

The employee contribution reduces taxable pay, but does not reduce employee NI pay.

Relief at source

The calculator deducts the employee contribution and applies basic-rate relief against income tax.

Salary sacrifice

The employee contribution reduces both taxable pay and pay for employee NI.

When qualifying earnings are enabled, pensionable pay is capped between £6,240 and £50,270 for the current tax year.

Annual Bonus

The calculator can include an annual bonus either as a fixed sum or as a percentage of base salary. A percentage bonus moves with the target salary in the pay rise comparison, which is useful for offers with a maximum bonus such as 10% or 20%.

Fixed amount

Enter the expected annual bonus in pounds. It is added to base salary as taxable gross income.

Percentage of salary

Enter the maximum bonus percentage. The calculator multiplies base salary by this percentage.

Tax treatment

Bonus is included for income tax, employee National Insurance, student loan, and postgraduate loan estimates.

Bonus month

When a bonus is entered, the results show a typical month and a bonus month. The bonus month includes the estimated net bonus as a single payment.

First iteration limit

Pension contributions are calculated from base salary only. Bonus-specific pension or payroll-period handling is not modelled yet.

Salary Sacrifice Schemes

Use the monthly salary sacrifice field for arrangements such as an electric vehicle or car salary sacrifice scheme. The calculator multiplies the monthly amount by 12, then reduces pay for income tax, employee National Insurance, student loan, and postgraduate loan calculations.

What is included

The sacrificed amount is deducted from estimated bank pay and appears in the deductions breakdown.

Tax and NI effect

The sacrificed amount reduces taxable pay and pay for employee NI before those deductions are calculated.

Loan effect

Student and postgraduate loan estimates are based on pay after this salary sacrifice.

Not yet included

Company car benefit-in-kind, employer-specific fees, insurance extras, early termination costs, and optional accessories are not modelled.

For EV schemes, the benefit-in-kind tax can still matter. This first iteration models the sacrificed salary only; it does not add car benefit-in-kind back into taxable pay.

Tax-Year Data

2026/27

Personal allowance

£12,570

Allowance taper starts

£100,000

Employee NI boundaries

£12,570 to £50,270

Qualifying earnings

£6,240 to £50,270

Income tax bands: England, Wales and Northern Ireland
Band Taxable income Rate
Basic rate Up to £37,700 20%
Higher rate £37,700 to £125,140 40%
Additional rate £125,140 and above 45%
Income tax bands: Scotland
Band Taxable income Rate
Starter rate Up to £2,827 19%
Basic rate £2,827 to £14,921 20%
Intermediate rate £14,921 to £31,092 21%
Higher rate £31,092 to £62,430 42%
Advanced rate £62,430 to £125,140 45%
Top rate £125,140 and above 48%
Loan thresholds
Loan type Annual threshold Rate
Plan1 £26,065 9%
Plan2 £28,470 9%
Plan4 £32,745 9%
Plan5 £25,000 9%
Postgraduate loan £21,000 6%

2025/26

Personal allowance

£12,570

Allowance taper starts

£100,000

Employee NI boundaries

£12,570 to £50,270

Qualifying earnings

£6,240 to £50,270

Income tax bands: England, Wales and Northern Ireland
Band Taxable income Rate
Basic rate Up to £37,700 20%
Higher rate £37,700 to £125,140 40%
Additional rate £125,140 and above 45%
Income tax bands: Scotland
Band Taxable income Rate
Starter rate Up to £2,827 19%
Basic rate £2,827 to £14,921 20%
Intermediate rate £14,921 to £31,092 21%
Higher rate £31,092 to £62,430 42%
Advanced rate £62,430 to £125,140 45%
Top rate £125,140 and above 48%
Loan thresholds
Loan type Annual threshold Rate
Plan1 £26,065 9%
Plan2 £28,470 9%
Plan4 £32,745 9%
Plan5 £25,000 9%
Postgraduate loan £21,000 6%

Not Included

The calculator is designed for a straightforward employee salary estimate. It does not currently model:

  • Employer National Insurance, employer pension contributions, or apprenticeship levy.
  • Emergency tax on specific payroll periods, cumulative/non-cumulative month-one handling, or HMRC payroll caps for unusual tax codes.
  • Marriage allowance, blind person's allowance, Scottish starter savings interactions outside the listed bands, or High Income Child Benefit Charge.
  • Benefits in kind, company cars, bonuses paid in specific payroll periods, dividends, savings interest, rental income, or capital gains.
  • Self-employment, director NI, umbrella company fees, salary sacrifice arrangements other than pension, or payroll-period rounding.
  • Employer-specific pension tax relief rules, annual allowance tapering, pension carry forward, or lifetime allowance protections.

Sources and Assumptions

The calculator uses tax-year rules based on published UK tax, National Insurance, pension, and student loan guidance. The values should be checked whenever HMRC, Student Loans Company, or Scottish Government guidance changes.