Net Cost After Tax Relief Calculator
See exactly what a salary sacrifice car really costs you each month after income tax relief, National Insurance savings, and benefit-in-kind tax are accounted for.
Frequently asked questions
What is the net cost of a salary sacrifice car?
The net cost is what you actually pay out of your take-home pay. It equals the gross lease cost minus income tax and NI savings, plus the BIK tax you owe, minus any employer NI passthrough. For an EV, the net cost is typically 30-50% less than the gross lease.
Why is the net cost different from the payslip deduction?
Your payslip shows the gross salary sacrifice deduction. But because that deduction reduces your taxable income, you also pay less tax and NI. The net cost reflects the actual reduction in your take-home pay, which is smaller than the gross deduction.
What is employer NI passthrough?
When you sacrifice salary, your employer saves 15% employer NI on the amount. Some employers pass part of this saving back to you as a discount on the lease. A 50% passthrough on a £400/month lease means you get an extra £30/month off (£400 x 15% x 50% / 12).
Is the net cost lower for higher earners?
Yes. Higher-rate (40%) and additional-rate (45%) taxpayers save more income tax per pound sacrificed than basic-rate (20%) taxpayers. Those in the £100k-£125k personal allowance taper band see the largest savings due to the effective 60% marginal rate.
These calculations are estimates based on 2026/27 HMRC and DVLA rates. Speak to a lender or qualified financial adviser for a personalised quote.