Finance⏱ 5 min read
How to Calculate Your Pension Lump Sum and Tax-Free Cash
Most UK pensions allow a tax-free cash lump sum of 25% at retirement. Here is how to calculate it, what crystallising the pension means, and how to choose between lump sum and income.
Taking pension tax-free cash is one of the few genuinely tax-free strategies available to UK taxpayers. Understanding how it is calculated and when to take it changes the financial picture significantly.
The 25% Tax-Free Cash Calculation
UK registered pension schemes allow you to take 25% of the pension fund
as a tax-free lump sum (Pension Commencement Lump Sum, PCLS).
Remaining 75% is drawn as taxable income (either via annuity or drawdown).
Example: pension pot of £320,000:
Tax-free lump sum: £320,000 x 25% = £80,000
Remaining for drawdown or annuity: £240,000
The £80,000 is received entirely tax-free -- no income tax, no CGT.
Maximum tax-free cash (2024/25):
No formal cap since Lifetime Allowance was abolished in April 2024.
However: effectively capped at £268,275 (the old LTA cap figure preserved)
Any tax-free cash above £268,275 is now subject to income tax.
Defined Benefit (DB) Pension Lump Sum
Final salary / career average pensions calculate lump sum differently:
Standard = 3/80ths of final salary per year of service
(Or commutation at rate set by scheme)
Example: 30 years service, final salary £45,000:
Standard lump sum: 3/80 x 45,000 x 30 = 3/80 x 1,350,000 = £50,625
Standard pension: 45,000 / 60 x 30 = £22,500/year
Commutation (exchanging pension for extra lump sum):
Typical commutation factor: £12 lump sum per £1 annual pension given up
Giving up £5,000/year pension: £5,000 x 12 = £60,000 extra lump sum
New annual pension: £22,500 - £5,000 = £17,500/year
Total lump sum: £50,625 + £60,000 = £110,625
Should You Take the Full Lump Sum?
Arguments FOR taking the 25% lump sum:
- It is completely tax-free income (your only 100% tax-free large sum)
- Remaining pot can still grow and be drawn
- If you die, the lump sum is already out of the pension (less IHT exposure)
Arguments AGAINST:
- Reduces the remaining pot for future income
- Lost investment growth on the 25% taken
- If you don't need the cash, you're drawing capital unnecessarily
Break-even calculation:
Lump sum: £80,000 invested externally at 5% = £4,000/year income
vs keeping in pension: £80,000 x 4% drawdown = £3,200/year
(Pension drawdown is taxable; external investment return may be partially taxable)
For basic rate taxpayers who need income:
Often better to take the tax-free cash (maximise tax-free sum)
and draw taxable income slowly to stay in basic rate band.
Timing: Phased Crystallisation
You don't have to crystallise (take PCLS) your whole pension at once.
Phased drawdown: crystallise portions over multiple tax years.
Example: £400,000 pension, want £10,000 tax-free cash per year:
Crystallise £40,000 per year: takes £10,000 (25%) tax-free
Remaining £30,000 available for drawdown (taxable)
Benefit: keeps more uncrystallised pension growing tax-free
Drawback: more admin; rules on recycling lump sum back to pension