UK Bonus Sacrifice into Pension Calculator 2026/27

What bonus sacrifice into pension actually does

A bonus paid through normal PAYE pays Income Tax at your marginal rate plus 8% (basic) or 2% (above the Upper Earnings Limit) of employee National Insurance. The employer also pays Class 1 secondary NIC on the bonus - 15% from 6 April 2025, applied to the bonus amount above the Secondary Threshold of £5,000. The worker only sees their personal deductions on the payslip; the employer NI is borne separately by the employer and never appears in the take-home figure.

Bonus sacrifice replaces that flow. You agree with your employer, in writing and before the bonus is paid, that some or all of the upcoming bonus will be paid as an employer pension contribution instead of as cash earnings. That single contractual change has three effects:

1. The sacrificed portion is no longer employment income, so no Income Tax is due on it.
2. The sacrificed portion is no longer earnings, so no employee NI (8% / 2%) is due on it.
3. The sacrificed portion is no longer in the employer’s pay bill, so the employer also avoids paying their 15% Class 1 secondary NIC.

What lands in your pension is the headline bonus amount. If your employer chooses to share back the 15% NIC saving they would otherwise have paid, the pension contribution becomes 115% of the headline bonus. A generous scheme can therefore turn a £10,000 bonus into £11,500 inside the pension pot.

Why bonus sacrifice is so much more powerful than regular salary sacrifice

The arithmetic is identical to ongoing salary sacrifice. The reason bonus sacrifice gets singled out in tax planning is that one-off bonuses often push earners into temporary high-marginal-rate bands - the £100,000-£125,140 Personal Allowance taper, the £125,140 additional rate, or the £100,000 child-benefit clawback threshold. Every pound paid in those bands costs more than 50p in tax and NI. Every pound sacrificed escapes that hit.

A worker on £100,000 base salary who receives a £10,000 bonus:

• Cash route: the £10,000 lands entirely in the PA taper band. 40% Income Tax + 2% NI = 42% deduction directly. The PA also shrinks by £5,000 (£1 for every £2 over £100k), reclassifying £5,000 of previously tax-free income at 40%. That’s an extra £2,000 hit on the salary, working out to a 62% effective marginal rate on the bonus. Net cash: about £3,800.
• Sacrifice route: £10,000 goes into pension. If the employer shares the 15% NIC saving, £11,500 lands. Worker keeps £11,500 in pension, locked but pre-tax, versus £3,800 in cash.

The same £10,000 produces three times as much wealth if sacrificed. That ratio is what drives the popularity of bonus sacrifice for the £100k-£125k earner segment.

Worked example: £130k base + £20k bonus

A mid-senior tech earner has £130,000 base salary and is awarded a £20,000 annual bonus. Their base is already above £125,140 so they have completely lost their Personal Allowance and are paying 45% additional rate on the marginal pound. The bonus lands fully in additional-rate territory.

• Cash bonus through PAYE: 45% Income Tax + 2% NI = 47% deduction. Net cash kept: £20,000 × 53% = £10,600. The employer also pays £3,000 of secondary NIC (15% × £20k) to HMRC - cost to employer: £23,000 gross to deliver £10,600 net.
• Sacrifice 100% into pension, employer does not share NIC: £20,000 lands in the pension pot. Worker has lost £10,600 of immediate cash but gained £20,000 of pension. At a 4% sustainable drawdown rate that’s £800/year of pension income for life vs a one-off cash sum.
• Sacrifice 100% into pension, employer shares 15% NIC: £20,000 base contribution + £3,000 shared NIC saving = £23,000 in the pension. The employer’s total bonus cost stays at £23,000 (matching the cash route’s true cost to them), but the worker receives £23,000 of pension instead of £10,600 of cash. A 117% improvement in retained value.

When sacrifice beats cash, and when it doesn’t

The sacrifice route wins on tax efficiency in almost every higher-rate scenario. It loses on:

• Liquidity: pension money is inaccessible until age 57 (rising to 58 in April 2028). If you need the cash for a house deposit, debt repayment, or emergency fund, take it as cash and pay the tax.
• Annual allowance: the £60,000 standard allowance (2026/27) caps tax-relievable pension contributions. If you and your employer combined already contribute above that, the bonus can trigger the Annual Allowance Charge - effectively negating the sacrifice benefit. Earners with adjusted income above £260,000 face a tapered allowance dropping to as little as £10,000.
• Lump Sum Allowance: the new £268,275 cap on tax-free pension lump sums (replaced the LTA in April 2024). Sacrificing into pension when you are already close to this ceiling means the extra growth will eventually be drawn at the marginal Income Tax rate, not 25% tax-free.
• Pension fund death taxes from April 2027: under planned reforms, uncrystallised pension funds become subject to Inheritance Tax. The shelter advantage shrinks for very large pots intended as a legacy.

The break-even decision usually turns on liquidity needs and existing pension pot size, not on tax arithmetic.

How to set up bonus sacrifice

The HMRC rules require that the sacrifice agreement is made before any contractual entitlement to the cash bonus arises. The standard practical approach is:

1. Your employer announces the bonus pool or schedule (typically in the last quarter of the financial year).
2. You request bonus sacrifice via payroll / HR / pensions portal at least one full pay period before the bonus payment date.
3. Payroll varies your employment contract for that pay period, recording the sacrifice as an irrevocable election.
4. On payday, the sacrificed amount is paid directly to your pension scheme as an employer contribution. The cash portion (if any) is processed through PAYE as normal.

A retrospective sacrifice (after the cash has already been paid) is not allowed and would be reclassified by HMRC as a regular pension contribution - eligible only for Income Tax relief, not the NI saving. The timing rule is strict.

Interaction with other thresholds and benefits

Bonus sacrifice reduces your adjusted net income, which can:

• Restore Personal Allowance if your income falls back below £125,140. Each £1 of sacrifice between £100k and £125k restores £0.50 of PA, doubling the saving.
• Eliminate or reduce HICBC (High Income Child Benefit Charge) if it drops your income below £80,000 (the 2026/27 threshold for full clawback above £80,000 with phase-in down to £60,000).
• Improve Tax-Free Childcare eligibility if it brings you under the £100,000 cap (each parent’s individual adjusted net income must be below this).
• Reduce student loan repayments if your sacrifice brings taxable pay below the plan threshold.

These knock-on effects often make sacrifice more attractive at lower incomes (£60k-£80k with children) than the raw marginal-rate analysis suggests.

What the calculator doesn’t model

This calculator focuses on the headline four-effect comparison: cash take-home, sacrificed pension contribution, employer NIC saving, and the delta vs all-cash. It assumes:

• Your sacrifice is correctly set up in advance (not retroactive).
• You have annual allowance headroom (we don’t apply the £60k cap or taper).
• Your reduced taxable salary stays above National Minimum Wage.
• No salary-related benefits (mortgage borrowing capacity, SMP, life cover) are affected. In practice, lenders increasingly accept salary-sacrifice pension contributions as an add-back when assessing mortgage affordability, but the policy is lender-specific.

For pension annual allowance modelling, use the Pension Annual Allowance Calculator. For the underlying salary mechanics, see the Salary Sacrifice Calculator. For an overview of bonus taxation in cash form, see the Bonus Tax Calculator.

Related guides

• Salary Sacrifice Explained - the wider mechanics and watch-outs.
• Pension Auto-Enrolment - the contribution floor most schemes build on.
• The 60% Tax Trap - why income between £100k and £125,140 attracts an effective 62% marginal rate.