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FinToolSuite
Updated April 20, 2026 · Income · Educational use only ·

Marginal vs Average Tax Calculator

Compare marginal rate to effective average rate.

Compare your marginal tax rate against your effective average rate — the gap explains why an extra dollar feels different from your 'tax bracket'.

What this tool does

Marginal rate applies to the next pound earned; average rate applies to all earnings to date — the gap matters for decisions about overtime, bonuses, or pension contributions. This calculator takes your gross income, total tax paid, and top marginal rate, then returns both your average tax rate and the gap between the two. The average rate is computed by dividing total tax by gross income. The result illustrates how much of each additional pound of earnings goes to tax versus how much tax you've paid on your overall income. This distinction is useful when modelling income scenarios where a change in earnings moves you into a higher tax bracket. The calculation is illustrative and assumes your marginal rate and tax figures are accurate for your jurisdiction; it does not account for allowances, deductions, or variations in tax structures.


Enter Values

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Formula Used
All tax paid on the income (entered as a percentage value)
Gross income for the period
Rate on the next pound earned (entered as a percentage value)

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Calculations or display — let us know.

Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

A taxpayer earning 60,000 with 14,000 of tax paid has a 23.3% effective average rate. If their marginal rate is 40%, the next 1,000 of income is taxed at 40% — not 23.3%. Confusing the two leads to bad decisions on whether to take overtime, salary-sacrifice into pension, or accept a bonus.

What the result means

Effective average is total tax over total income. Marginal is the rate on the next pound. The gap is the marginal minus the average and shows how much more painful additional income is than the average suggests.

Use the marginal rate when deciding whether to take an extra job, accept a bonus, or contribute more to a pension. Use the average rate when assessing affordability or comparing year-on-year totals.

Run it with sensible defaults

Using gross annual income of 60,000, total tax paid of 14,000, marginal rate of 40%, the calculation works out to 23.33%. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Gross Annual Income, Total Tax Paid, and Marginal Rate — do not pull with equal force. Two inputs usually tip the answer one way or the other. Identify which ones matter most by flipping each value past a round threshold and watching whether the option with the lower calculated total changes.

How the math works

Average rate is total tax divided by gross income. Gap is the difference between the supplied marginal rate and the calculated average. Both are expressed as percentages.

Using this in pay negotiations

Knowing the exact figure behind a headline rate gives you specific numbers to anchor to in conversations about pay. "The difference is £X per month after tax" lands harder than "a couple of grand a year". Concrete numbers move decisions.

What this doesn't capture

Tax bands, pension contributions, student-loan deductions, and benefits-in-kind sit outside this calculation. The figure is the headline; your actual position depends on local tax rules and personal circumstances. Pair with a dedicated take-home calculator for the full picture.

Example Scenario

At £60,000 income with £14,000 paid, your effective average tax rate is 23.33%, compared to your marginal rate of 40.

Inputs

Gross Annual Income:£60,000
Total Tax Paid:£14,000
Marginal Rate:40
Expected Result23.33%

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

This calculator computes two core metrics to illustrate the relationship between marginal and average tax rates. The average tax rate is calculated by dividing total tax paid by gross annual income, then multiplying by 100 to express the result as a percentage. The gap between rates is found by subtracting the calculated average rate from the supplied marginal rate. The calculator assumes that the marginal rate provided represents the tax rate applicable to the next unit of income earned. It does not model progressive tax bracket structures, account for deductions or allowances, adjust for tax credits, or incorporate changes in rates across different income levels. Results are presented as percentages for comparison purposes.

Frequently Asked Questions

Why are they different?
Most tax systems use bands. Lower bands tax at lower rates, so the average across all earnings is below the rate on the highest band — which is the marginal.
Which to use to decide a pension contribution?
The marginal rate. Pension contributions reduce taxable income from the top down, so you save tax at the marginal rate, not the average.
What about overtime?
Same — extra income lands on top, taxed at the marginal rate. Use the marginal figure to assess whether overtime is potentially useful.
Why isn't the gap zero?
If the gap is zero, you are in a flat-tax system or your entire income falls within one band. Most progressive systems will show a positive gap.

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