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

Bonus to Pension Conversion Calculator

Compare cash bonus vs pension contribution.

Compare taking a bonus as cash versus routing it into your pension — see the long-term wealth difference at compounding rates.

What this tool does

This calculator models the outcome of choosing between receiving a bonus as cash or routing it into a pension. It calculates the net cash value after tax and the projected future value of the pension contribution based on your expected investment return and time horizon. The comparison shows how each path grows (or doesn't) until retirement. The result is driven primarily by your marginal tax rate, the annual return you anticipate, and how many years the money has to grow. A typical scenario: an employee receiving a discretionary bonus and needing to understand the long-term retirement impact of each option. Note that the calculation doesn't account for taxes owed when you eventually withdraw from the pension, so the actual retirement value may differ. Results are for illustration only and don't reflect individual circumstances or regulatory rules.


Enter Values

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Formula Used
Gross bonus
Combined marginal rate (entered as a percentage value)
Annual return (entered as a percentage value)
Years to retirement

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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 10,000 bonus taken as cash at 42% combined tax leaves 5,800. The same 10,000 sacrificed to pension and grown at 5% for 20 years becomes 26,533 — almost 5× the cash equivalent before any drawdown tax. Even after retirement tax of 25-30%, the pension route usually wins for long horizons.

What the result means

Pension route is the future value of the gross bonus invested for the period. Cash route is the after-tax cash today. Compare both to your priorities — pension wealth at retirement vs cash now.

Quick example

With gross bonus of 10,000 and combined marginal rate of 42% (plus expected annual return of 5% and years to retirement of 20), the result is 26,532.98. 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 Gross Bonus, Combined Marginal Rate, Expected Annual Return, and Years to Retirement. 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

Pension future value is gross bonus compounded at the supplied return for the years to retirement. Cash route applies the marginal rate to the gross. Drawdown tax in retirement is not netted off — apply separately if comparing net retirement income. 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

Converting a £10,000 bonus at 42 tax grows to 26,532.98 over 20 years at 5 annual return.

Inputs

Gross Bonus:£10,000
Combined Marginal Rate:42
Expected Annual Return:5
Years to Retirement:20
Expected Result26,532.98

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

The calculator computes two scenarios. For the pension route, it applies compound growth to the gross bonus amount at the expected annual return rate over the years remaining until retirement, using the formula FV = Gross × (1+r)^n. For the cash route, it reduces the gross bonus by the combined marginal tax rate, treating this as the net amount received. The model assumes a constant annual return, ignores investment fees and charges, and does not account for taxes applied during drawdown in retirement—these should be assessed separately when comparing net retirement income between the two routes.

Frequently Asked Questions

What about retirement tax?
Drawdown is taxed at retirement, sometimes at lower rates. Even after tax, pension route usually wins for horizons over 10 years.
Lifetime allowance risk?
If your pot is approaching the lifetime allowance, additional contributions may face a tax charge — review carefully.
Is cash ever better?
If you need the money now (debt, deposit), or expect to be in a upper rate at retirement than today, cash applies.
Employer NI rebate?
Some employers pass on the employer NI saving on bonus sacrifice — that can add 13.8% to the pension contribution. Check employer policy.

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