How the KiwiSaver calculators work

Two figures, and why they differ

Every projection shows two figures. The annual statement figure follows Schedule 7A of the Financial Markets Conduct Regulations 2014, the formula every KiwiSaver provider must use on your annual statement. The year-by-year model runs one year at a time, so it can include the move to 4% on 1 April 2028 and work out ESCT and the government contribution for each year.

The figures differ because the annual statement follows the Schedule 7A formula, which keeps today’s contribution rates to 65 and rounds to the nearest $1,000, while the year-by-year model also includes the move to 4% on 1 April 2028 and works out ESCT and the government contribution for each year.

The Schedule 7A formulas

N is 65 minus your age, rounded to the nearest whole year. m is this year’s contributions from you and your employer (after ESCT), n is the government contribution, p is your balance now. Midpoints round up.

Balance at 65 (when g is not equal to k)

c = m × ((1+g)^N − (1+k)^N) / (g − k) + n × ((1+g)^N − 1) / g + p × (1+g)^N

Balance at 65 (when g equals k)

c = m × N × (1+g)^(N−1) + n × ((1+g)^N − 1) / g + p × (1+g)^N

In today’s dollars

b = c / (1+d)^N, rounded to the nearest $1,000

Weekly to age 90

r = b × (7 / 365.25) × (h − d) × (1+h)^(s−e−0.5) / ((1+d)^0.5 × ((1+h)^(s−e) − (1+d)^(s−e))), rounded to the nearest $10

The year-by-year model

Each year from your age to 65 the model adds your contributions, your employer’s contribution after ESCT and the government contribution, then the year’s return on the balance. Pay grows by 3.5% a year.

Your rate and your employer’s minimum follow the law: 3.5% now and 4% from 1 April 2028 (the model applies the step from its third year). If you choose 4%, 6%, 8% or 10%, your rate stays there and your employer’s minimum still steps up.

ESCT is worked out each year from your pay plus your employer’s contribution, using these bands: 10.5% up to $18,720, 17.5% up to $64,200, 30% up to $93,720, 33% up to $216,000, 39% over $216,000. The government contribution is 25 cents per dollar up to $260.72, nothing over $180,000, and stops at 65.

Fees in the fees calculator are taken off the assumed return, and member fees off the balance each year. Today’s dollars take out 2% inflation a year.

With pay growth and the 2028 step switched off, the model matches the Schedule 7A formula to the cent. That check runs before every publish.

What the calculators do not include

• Part-year government contributions, for people who join or turn 16 or 65 during the year. The proration formula in the Income Tax Act has not been confirmed, so test GC10 stays marked as unverified.
• Which tax year’s income the $180,000 cap is tested on. That depends on when your tax return is filed, so it is explained, not calculated (tests GC6 and GC7).
• Savings suspensions, hardship withdrawals, market ups and downs, and changes to the law after 10 November 2026.