GeraCash / UK Tax Calculator / Methodology
Gera Effective Tax Rate (GETR) — Methodology
Full reproducible formula behind the Gera Effective Tax Rate (GETR), computed only from HMRC's published 2024-25 income tax and NIC rates (Open Government Licence v3.0).
What is the Gera Effective Tax Rate (GETR)?
The Gera Effective Tax Rate (GETR) is a Gera-computed metric that expresses the combined income tax and employee Class 1 NIC burden as a single percentage of gross earnings:
GETR = (income_tax + employee_NIC) / gross_salary × 100Unlike the headline income-tax rate, GETR includes National Insurance — the second mandatory deduction on employment income — making it the true cost of earning £1 more. A higher GETR means more of each additional pound goes to the Exchequer. Gera publishes GETR figures for every salary band across England/Wales/ Northern Ireland and Scotland so taxpayers can compare their position at a glance.
Step 1 — Income tax
England, Wales and Northern Ireland
Source: HMRC Income Tax rates and allowances, England, Northern Ireland and Wales table, 2024-25.
| Band | Rate | Taxable income range |
|---|---|---|
| Personal Allowance | 0% | Up to £12,570 |
| Basic rate | 20% | £12,570–£50,270 |
| Higher rate | 40% | £50,271–£125,140 |
| Additional rate | 45% | Above £125,140 |
Personal Allowance tapers by £1 for every £2 of income above £100,000, reaching zero at £125,140.
Scotland
Source: HMRC Income Tax rates and allowances, Scotland table, 2024-25.
| Band | Rate | Gross income range |
|---|---|---|
| Personal Allowance | 0% | Up to £12,570 |
| Starter rate | 19% | £12,571–£14,876 |
| Basic rate | 20% | £14,877–£26,561 |
| Intermediate rate | 21% | £26,562–£43,662 |
| Higher rate | 42% | £43,663–£75,000 |
| Advanced rate | 45% | £75,001–£125,140 |
| Top rate | 48% | Above £125,140 |
Step 2 — Employee NIC (Class 1, Category A)
Source: HMRC Rates and thresholds for employers 2024-25. NIC rules are reserved (UK-wide) — they apply equally in England, Scotland, Wales and Northern Ireland.
| Earnings band | Rate | Annual threshold |
|---|---|---|
| Below Primary Threshold | 0% | Up to £12,570 |
| Main rate | 8% | £12,570–£50,270 |
| Additional rate | 2% | Above £50,270 |
Step 3 — Gera Effective Tax Rate (GETR)
GETR = (income_tax + employee_NIC) / gross_salary × 100Rounded to one decimal place. Example at £35,000 gross (England/Wales/NI):
employee_NIC = £1,794
gross = £35,000
GETR = (£4,486 + £1,794) / £35,000 × 100
GETR = 17.9%
What GETR does not include
- –Employer NIC (a cost to the employer, not a deduction from pay)
- –Pension contributions — depend on individual auto-enrolment opt-in and employer scheme
- –Student loan repayments (Plans 1, 2, 4, 5) — depend on plan type and income
- –Child Benefit high-income charge
- –Marriage Allowance, Blind Person's Allowance, or other individual allowances
- –Benefits in kind or other non-cash remuneration
- –Income from sources other than employment (savings interest, dividends, rental income)
GETR is the statutory minimum deduction rate on employment income — the base from which any personalised net calculation starts.
Licence and attribution
Contains public sector information published by HM Revenue & Customs and licensed under the Open Government Licence v3.0. Source: HMRC — Income Tax rates and allowances: current and past (tax year 2024-25).
Contains public sector information published by HM Revenue & Customs and licensed under the Open Government Licence v3.0. Source: HMRC — Rates and thresholds for employers 2024 to 2025 (tax year 2024-25).
Gera's computation (the GETR formula and the salary grid) is original work by Gera Systems Ltd. The underlying rate/threshold data is Crown copyright, published by HMRC under the Open Government Licence v3.0. Last updated: 2026-06-20.