UK pension tax planning

UK Workplace Pension Calculator

Before you take that luctrative looking job in the Gulf, Let's model you pension over 20 years, does the Gulf Package look as good?

Estimated pension pot after 20 years, Heading to the Gulf?
Remember to account for this number or you will be left behind!
£165,329

Annual pension input

£3,200

5% employee + 3% employer

Tax relief element

£400

1% tax relief inside the 5% employee total

Employee net cost

£1,600

4% from take-home pay at the default

£267/month is flowing into your pension - employee contribution, employer match and tax relief combined. Most people never see this number when they budget, and it matters.

// Pension inputs
£40,000
5%

In many auto-enrolment schemes the common minimum is 5% employee: 4% from take-home pay plus 1% basic-rate tax relief.

3%
// Projection settings
Contribution basis

Auto-enrolment often uses qualifying earnings between £6,240 and £50,270, but many employers use full salary.

5%

20-year pension projection

Full salary basis
Your net annual cost
£1,600
4% of pensionable salary at the default
Government tax relief
£400
1% of pensionable salary at the default
Employer annual input
£1,200
Employer contribution
Salary Sacrifice & Pension Calculator | ExpatMoneyMatters Line chart showing pension value increasing over 20 years.
Salary sacrifice layer

Am I better off with salary sacrifice?

In almost all cases, salary sacrifice can be a more tax-efficient way to save for retirement. Model that below

20-year pension comparison: standard vs sacrifice

Current rules
Standard contribution pot
£165,329
Workplace pension only, no sacrifice
With salary sacrifice
£217,900
Workplace pension plus sacrifice and any pass-back
Extra pot at retirement
£52,600
At 4% withdrawal: £2,104/year indefinitely
Salary Sacrifice & Pension Calculator | ExpatMoneyMatters Dual line chart. The salary sacrifice line grows higher than the standard contribution line because National Insurance savings compound over 20 years.
// Sacrifice settings
£5,000

This is the gross salary you give up. Your employer pays the same amount into your pension instead.

Rules to model

April 2029 mode applies the £2,000 annual NIC exemption cap for pension salary sacrifice.

0%
// Minimum wage check
£12.21/hr
37.5 hrs

This sacrifice appears above the hourly minimum wage floor on the assumptions entered.

Why the gap keeps widening

Standard pension contributions attract income tax relief but National Insurance is still charged on your original salary. Salary sacrifice avoids NI completely on the sacrificed amount, so more money enters your pension from day one. Investment growth then acts on a larger base every year - which is why the gap between the two lines accelerates over time rather than staying flat.

Salary sacrifice result

Current rules
Standard monthly take-home
£4,000
After tax, NI and standard pension cost
Sacrifice monthly take-home
£3,600
After lower salary, tax and NI
Monthly better off
£2,000
Employee NI saving plus pass-back
Feature Standard contribution Salary sacrifice
Contractual gross salary £40,000 £35,000
Amount paid into pension £5,000 £5,000
Income tax saved £1,000 £1,000
Employee NI saved £0 £400
Employer NI saved £0 £750
Net cost to employee £4,000 £3,600
Employee NI saved £160
Employer NI saved £300
Employer pass-back £0

What salary sacrifice means

A salary sacrifice arrangement, sometimes called salary exchange, is a formal change to your employment contract. Instead of receiving your full cash salary and then paying into a workplace pension, you agree to reduce your gross pay by a set amount. Your employer then pays that amount directly into your pension as an employer contribution.

Because your official gross salary is lower, income tax and National Insurance are calculated on a lower pay figure. In a standard pension setup you usually get income tax relief, but you still pay employee NI on your original salary. Salary sacrifice lowers the pay figure first.

For the employee

You save income tax at your marginal rate and may also save employee NI: usually 8% in the main NI band or 2% above the Upper Earnings Limit.

For the employer

The employer may save 15% Class 1 employer NI on the sacrificed amount. Some employers keep this; others pass some or all of it into your pension.

The pension boost

If employer NI savings are passed back, your pension can grow faster without increasing the employer's total employment cost.

Methodology

How the workplace pension calculator works

The calculator starts with annual employee and employer pension contributions, projects them for 20 years, then estimates income tax, employee Class 1 National Insurance and employer Class 1 National Insurance before and after salary sacrifice.

1. Workplace pension input

The default is the common 8% auto-enrolment minimum: 5% employee and 3% employer. The employee percentage includes basic-rate tax relief.

2. Twenty-year projection

Annual contributions are added once per year and compounded at your selected growth rate to show an illustrative pension pot after 20 years.

3. Salary sacrifice

The employee gross pension contribution is then treated as the sacrifice amount. Current and April 2029 cap modes show the NI difference.

Important limitations
  • Income tax is modelled for England, Wales and Northern Ireland, not Scottish bands.
  • The calculator assumes a standard employee NI category A profile.
  • Workplace pension minimums can be based on qualifying earnings or full salary, depending on scheme rules.
  • It does not model student loans, child benefit taper, childcare, benefit entitlement or statutory pay.
  • Employer pass-back is optional. Many schemes pass back none, some, or all of the employer NI saving.

Sources

Frequently Asked Questions

Is the minimum really 8%?

In most automatic enrolment defined contribution schemes, yes: the total minimum is 8%, with at least 3% from the employer and the employee usually paying 5%. That employee 5% normally includes 1% basic-rate tax relief, so the take-home cost is closer to 4% for a basic-rate taxpayer.

Why does salary sacrifice save more than a normal pension contribution?

A normal pension contribution usually gives income tax relief, but employee NI is still charged on your original salary. Salary sacrifice lowers contractual pay before NI is calculated, so the same pension contribution can cost less in take-home pay.

What happens from April 2029?

From 6 April 2029, the NI exemption for employee pension contributions through salary sacrifice is capped at £2,000 per tax year. Amounts above that still receive income tax relief, but the additional NI saving is removed.

This calculator is an educational planning tool. Salary sacrifice changes your employment contract and can affect pay-linked benefits, statutory pay, borrowing and minimum wage checks. Confirm details with your employer, payroll team or regulated tax adviser.