SIP Tax Savings Calculator
Isolate exactly how much Income Tax and National Insurance your SIP partnership contribution could save, at your own tax band.
Why buying from gross salary saves tax
Partnership shares are deducted from your salary before Income Tax and National Insurance are calculated — the same principle behind salary-sacrifice pension contributions. That means every £1 you direct into partnership shares would otherwise have cost you £1 plus whatever Income Tax and NIC applied to it as ordinary pay.
Free and matching shares work differently: since they cost you nothing, there's no "saving" to calculate in the same sense — but their value is delivered to you without Income Tax or NIC at the point of award, unlike an equivalent cash bonus, which would be fully taxed.
What this doesn't cover
This tool estimates tax saved on the way in. What happens when shares eventually leave the trust depends on how long you've held them — see the Holding Period Calculator and our guide on holding period rules.
Read the full explanation with worked examples: SIP Tax Benefits Explained.