SupaCalc
SupaCalc
CalculatorsProResources
Home
Resources
Glossary
Marginal Rate
Income Tax

Marginal Rate

The rate of tax you pay on your next pound of income, which can be higher than your effective rate due to allowance withdrawal.

Key Points

  • ✓Tax rate on your next pound of income
  • ✓Includes Income Tax + National Insurance (+ Student Loan if applicable)
  • ✓60% trap between £100k-£125k due to Personal Allowance withdrawal
  • ✓Different from your effective/average tax rate
  • ✓Crucial for financial planning decisions

Detailed Explanation

Your Marginal Rate is the tax rate you pay on your next pound of income. It's different from your effective (average) tax rate and is crucial for making financial decisions about overtime, bonuses, or Pension Contribution.

For most people, Marginal Rate equals their highest Income Tax rate plus National Insurance: 32% for Basic Rate Tax payers (20% + 12%), 42% for Higher Rate Tax payers (40% + 2%), and 47% for Additional Rate Tax payers (45% + 2%).

However, the highest Marginal Rate in the UK is actually 60%, applying to income between £100,000 and £125,140. This is because every £2 earned reduces your Personal Allowance by £1, effectively adding an extra 20% tax.

If you have a Student Loan, add 9% (or 6% for postgraduate). A Higher Rate Tax payer with a Plan 2 Student Loan has a Marginal Rate of 51% (40% + 2% + 9%).

Understanding your Marginal Rate helps you make better financial decisions. For example, a £1,000 pension contribution saves £600 for someone in the 60% bracket, but only £320 for a Basic Rate Tax payer.

Practical Examples

  • •Basic Rate Tax payer: 20% Income Tax + 12% National Insurance = 32% Marginal Rate
  • •Earner at £110,000: 40% + 2% + 20% (allowance loss) = 62% Marginal Rate on next £15,140
  • •Higher Rate Tax payer with Plan 2 Student Loan: 40% + 2% + 9% = 51% Marginal Rate

Related Resources

Frequently Asked Questions

Related Terms

Income Tax

Income Tax

A progressive tax on your earnings, charged at 20%, 40%, or 45% depending on your income level (after personal allowance).

National Insurance

National Insurance (NI)

Mandatory contributions that fund State benefits including the State Pension, charged at different rates for employees, employers, and self-employed.

Allowances

Personal Allowance

The amount of income you can earn tax-free each year (£12,570 for 2024/25), reduced if you earn over £100,000.

Income Tax

Higher Rate Tax

Income Tax charged at 40% on income between £50,271 and £125,140 (2024/25).

Income Tax

Additional Rate Tax

The highest Income Tax band in the UK, charged at 45% (47% in Scotland) on income over £125,140.

Calculate Your Take-Home Pay

Use our free UK salary calculator to see how marginal rate affects your actual take-home pay. Get instant, accurate calculations with full breakdowns.

SupaCalc
SupaCalc

Free UK salary calculator with instant take-home pay calculations and comprehensive tax planning tools.

Calculators

  • Take Home Pay
  • Salary Sacrifice
  • Pension Calculator
  • Student Loan
  • Benefits vs Work
  • View All Calculators →

Resources

  • Tax Codes Explained
  • UK Tax Bands
  • National Insurance
  • Pension Guide
  • Student Loans
  • IR35 Guide

Learn

  • Tax Glossary
  • Blog & Guides
  • What is Take Home Pay?
  • Personal Allowance
  • Marginal Tax Rate

Company

  • Pricing
  • Pro Features
  • Privacy Policy
  • Terms of Service
  • Usage Policy

© 2025 SupaCalc. All rights reserved. UK Tax Year 2025/26.

Calculations are estimates only. Always consult HMRC or a qualified tax professional for official guidance.