Top-slicing relief calculator

The full five-step computation, including the post-2021/22 Personal Savings Allowance recalculation (IPTM3820) most tools skip.

— Inputs

Gain, years, income.

Chargeable event gain

From the certificate, or the chargeable-event-gain calculator.

Complete years (N)

Relevant years for slicing — usually on the certificate.

Non-savings income (gross)

Salary, pension, self-employment, rental — gross, before the personal allowance.

Other savings income

Interest only — excludes dividends and the bond gain.

Dividend income

Taxed at the dividend rates as the top slice. Excludes the bond gain.

Bond type

Onshore bonds carry a deemed 20% basic-rate credit; offshore do not.

Tax year of the event

Drives the bands, PSA and allowances — versioned per-year config.

Need the gain first? Run the chargeable event gain calculator and bring the figure here.

Top-slicing relief

£5,846

Net additional tax due after relief and the 20% onshore credit: £0.00

The five steps

1 · Tax on full gain in income£11,332.00

2 · Tax without the gain£5,486.00

Tax attributable to the gain£5,846.00

3 · Annual equivalent (gain ÷ 8)£5,000.00

4 · Tax on slice at notional income£0.00

Relieved liability (× 8)£0.00

5 · Relief (Step 2 result − Step 4 result)£5,846.00

The PSA recalc — watch it move

PSA at Step 3 (full income + gain): £500.00
PSA at Step 4 (notional income + slice): £1,000.00

The Step-4 PSA is larger than Step 3’s — the IPTM3820 recalculation at notional income level is doing real work in this case. A tool that carries Step 3’s PSA into Step 4 understates the relief.

IPTM3820 · HMRC Agent Update 83 (2021) · config 2026-27-v1.4