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FinToolSuite
Updated May 14, 2026 · Income · Educational use only ·

After-Tax Yield Calculator

Yield kept after tax on investment income.

Calculate after-tax yield on bonds or savings by entering your pre-tax yield and marginal income tax rate to see the return you actually keep.

What this tool does

Two investments at the same headline yield can leave very different amounts after tax. This calculator models how tax on investment income reduces the actual return you keep. You enter the pre-tax yield, your marginal tax rate on that income, and the principal amount. The calculator then estimates the after-tax yield, the cash income generated, the portion you retain after tax, and the total tax paid across the year. The marginal tax rate is the primary driver of the result—higher rates significantly compress the after-tax outcome. The tool illustrates scenarios like comparing bond yields or dividend income across different tax situations. Results assume tax is levied at a single flat rate and do not account for tax relief, deductions, or timing of payments. This is for educational modelling only.


Enter Values

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Formula Used
Headline yield as a decimal
Marginal income tax rate as a decimal

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Disclaimer

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

A 5% pre-tax savings yield at a 40% marginal rate is a 3% after-tax yield. On 10,000 that means 300 kept versus 500 of headline income. Comparing taxable bonds, tax-free wrappers and dividend-paying assets requires comparing them on after-tax yield, not the headline number.

What the result means

After-tax yield is what you actually grow assets by. Use it to compare a taxable account against a sheltered wrapper at the same headline yield, or to compare two products at different headline yields and tax treatments.

The same math gives the equivalent taxable yield needed to match a tax-free product: divide the tax-free yield by (1 − tax rate).

Quick example

With pre-tax yield of 5% and marginal tax rate of 40% (plus investment amount of 10,000), the result is 3.00%. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Pre-Tax Yield, Marginal Tax Rate, and Investment Amount. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

What's happening under the hood

After-tax yield is the pre-tax yield multiplied by one minus the marginal rate. Cash income is principal times pre-tax yield; cash kept is principal times after-tax yield; tax paid is the difference. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

What the headline number hides

Gross pay, net pay, and what actually lands in your account can differ by thousands depending on tax code, benefits, pension contributions, and student loan deductions. This tool isolates one piece of that picture — always pair it with a take-home calculator for the full view.

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

An investment of £10,000 at 5 pre-tax yield becomes 3.00% after accounting for 40 in taxes.

Inputs

Pre-Tax Yield:5
Marginal Tax Rate:40
Investment Amount:£10,000
Expected Result3.00%

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 after-tax yield by applying the marginal tax rate to the pre-tax yield. The calculation multiplies the pre-tax yield by the factor (1 minus the marginal tax rate), producing the yield rate retained after tax. The annual cash income is derived by multiplying the investment amount by the pre-tax yield. The after-tax cash income is then calculated by multiplying the investment amount by the after-tax yield. The tax paid is the difference between these two income figures. The model assumes a constant marginal tax rate applied uniformly to all investment income and does not account for progressive tax brackets, variations in tax treatment across income types, transaction fees, timing effects, or changes in tax rates over time.

Frequently Asked Questions

Why care about after-tax yield?
It is the yield that actually grows your wealth. Two products with different headline yields can be ranked correctly only after tax is applied.
What rate ranges are typical?
The marginal rate on the income type. Savings interest, dividends, capital gains and bond coupons are sometimes taxed differently — pick the rate that applies.
Does this work for tax-free wrappers?
Set the rate to 0% to see the headline yield as the after-tax yield. Compare that to a taxable equivalent's after-tax yield to see the wrapper's value.
Inflation?
After-tax is a step on the way to after-tax real return. Subtract inflation (or use the Fisher formula) on the after-tax yield to get real growth.

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