Getting a bonus is great — but many New Zealanders are surprised at how much PAYE is deducted from it. Bonuses feel heavily taxed because they are added to your regular pay, pushing the combined amount into a higher tax rate. Understanding how bonus tax works (and why you often get some back at year end) can reduce the sting.
Bonuses are taxed as "extra pay" — your employer calculates a tax rate based on your annualised earnings including the bonus. This means a large bonus in a single month is taxed at a rate reflecting your total annual income, not just that month's income. If the bonus pushes your apparent annual income into a higher bracket than your actual annual earnings, you may have too much PAYE deducted — and get a refund in your end-of-year assessment. You do not pay more than your correct annual tax overall.
Why Bonuses Feel Overtaxed
Here is the key issue: PAYE is calculated each pay period as if you would earn that same amount every pay period for the whole year.
If your regular weekly salary is $1,500 (≈ $78,000/year) and you get a $10,000 bonus in one week, your employer calculates PAYE as if you earn $1,500 + $10,000 = $11,500 every week = $598,000/year. That implies the top 39% rate on the bonus.
This is clearly not your actual annual income. The extra pay method corrects for this — but the calculation can still result in more PAYE deducted from the bonus than you ultimately owe.
The Extra Pay Method
IRD requires employers to use the extra pay method for bonuses, commissions, back pay, and other lump sum payments:
Step 1: Annualise Regular Earnings
Take your regular earnings in the most recent pay period and multiply by the number of pay periods in a year:
- Weekly pay: $1,500 × 52 = $78,000
Step 2: Estimate Tax on Regular Earnings
Using the PAYE tables, determine the tax on your annualised regular earnings:
- Tax on $78,000: approximately $19,420
Step 3: Add the Bonus and Re-calculate
- Annualised regular + bonus: $78,000 + $10,000 = $88,000
- Tax on $88,000: approximately $23,620
Step 4: Tax the Bonus
- Difference: $23,620 − $19,420 = $4,200 PAYE on the $10,000 bonus
- Effective rate on the bonus: 42%
This is higher than the 33% rate that applies to income between $70,000–$180,000, because the method attributes the bonus at the margin — the highest dollars of your simulated income.
At Year End
At year end, IRD assesses your total actual earnings. If your total salary + bonus ($88,000 in this example) falls within the 33% bracket, any over-deducted PAYE will be refunded in your automatic assessment.
Common Extra Pay Situations
| Payment type | Taxed as extra pay? |
|---|---|
| Annual performance bonus | Yes |
| Christmas bonus | Yes |
| Commission lump sum | Yes |
| Back pay (owed wages) | Yes |
| Signing bonus | Yes |
| Overtime (same pay period) | Usually included in regular pay |
| Redundancy payment | Yes — see Redundancy Tax NZ |
Getting Your Bonus Money Back
If too much PAYE was deducted from your bonus:
- Automatic assessment — IRD assesses your total income at year end and issues a refund if you overpaid
- IR3 return — if you file an income tax return (self-employed or rental income), any overpaid PAYE is refunded or offset
Most employees with a single employer and a straightforward tax situation get an automatic refund if their bonus pushes them over-deducted.
KiwiSaver on Bonuses
KiwiSaver contributions are deducted from bonus payments:
- Your employee KiwiSaver contribution (3%–10%) is taken from the gross bonus
- Your employer also makes a 3% minimum employer contribution on the bonus
This is unlike redundancy payments, which are excluded from KiwiSaver.
Salary Sacrifice and Bonuses
Some employees have arrangements where they salary-sacrifice a portion of their bonus into KiwiSaver or another benefit. This reduces the cash bonus but also reduces PAYE. See Salary Sacrifice NZ for details.
Frequently Asked Questions
Why was my $5,000 bonus taxed at nearly 40%?
The extra pay method can push the effective rate on the bonus above your usual marginal rate. However, you will not owe that rate on your whole income — any over-deducted PAYE will be refunded in your automatic assessment at year end. Your overall tax bill for the year will be correct.
Can I ask my employer to spread my bonus over several months to reduce tax?
If the payment is genuinely paid monthly, each month’s contribution would be included in regular pay rather than as a lump sum. However, if it is contractually a lump sum bonus, it must be taxed as extra pay when it is paid. Artificially splitting it to reduce PAYE is not appropriate.
My employer taxed my bonus at my flat marginal rate (e.g., 33%). Is that acceptable?
Some employers apply a simplified flat rate rather than the strict extra pay method. This may over-deduct or under-deduct slightly. Any difference is corrected in the year-end assessment.
Do bonuses affect my student loan repayments?
Yes — student loan repayments (12% of income over the repayment threshold) apply to extra pay including bonuses. These deductions also appear on your payslip alongside PAYE.