Unpaid Invoice Recovery Calculator NZ 2026
Reviewed 7 August 2026. Disputes Tribunal fees current at August 2026.
The decision about an overdue invoice is rarely about principle, even though it always feels like it. It is a commercial question with a number attached: what will you actually keep, after the cost of getting it. That cost is mostly your own time, which is why small invoices are so often not worth pursuing formally, and why the answer changes completely between a $400 invoice and a $14,000 one. The fixed costs of recovery, whether that is a filing fee, an agency's minimum, or simply the hours of phone calls and letters, do not shrink in proportion to the debt. This calculator prices the three things that determine the answer: any interest your terms of trade actually entitle you to, the money cost of the recovery route you choose, and the value of the hours you will spend. It also gives you the break-even, which is the number of hours beyond which you are working for nothing.
Where it goes
What happens if they only pay part of it
Recovery costs are largely fixed, so a partial settlement does not reduce them proportionally.
| Recovered | Amount | Cost of recovery | Net to you |
|---|
Interest is only yours if you agreed it first
New Zealand has no general statutory right to interest on late commercial payment. That surprises people who have worked in jurisdictions that do, and it means an interest line added to a reminder after the invoice went unpaid carries no weight on its own. What creates the entitlement is your terms of trade: a written term, provided to the client and accepted before the work began, setting out a rate for overdue accounts. If you have that, the interest is real and worth including here. If you do not, set the rate to zero, and treat writing proper terms as the actual lesson from this invoice.
Your time is the largest cost, and the one people leave out
No money leaves your account when you spend an afternoon chasing a debt, which is exactly why that afternoon gets treated as free. It is not. If those hours would otherwise have been billable then the cost is the full charge-out rate, and on a small invoice a handful of hours can consume the entire debt. This is the single most common error in the decision: people pursue an invoice to a successful conclusion and never notice that the pursuit cost more than the recovery. The break-even figure on this page exists to make that visible before you start rather than after.
The routes, and what each really costs
Chasing it yourself costs only time, which makes it the right first move almost always, and a polite call on the day payment falls due resolves more invoices than any formal process. A debt collection agency converts your time into a percentage, which is usually worth it on larger or older debts where you have run out of leverage. The Disputes Tribunal costs a fixed filing fee and a lot of your own time, and lawyers are not permitted, so there are no legal fees. It is the right route when the client can pay and simply will not. None of the three is any use against a client who genuinely has no money, and recognising that case early saves more than any of them.
Worked example
A $4,000.00 invoice is 90 days overdue. The terms of trade provide for 10% interest on overdue accounts, which over 90 days adds $98.63, bringing the total owed to $4,098.63. The sole trader expects to spend 6 hours on calls, letters and follow-up, and their time is worth $85.00 an hour, so the recovery costs $510.00.
Recovering in full leaves $3,588.63, and the recovery cost is 12.75% of the original invoice. The break-even is 48.2 hours: beyond that the chase is worth less than the debt. Because the cost is mostly fixed, a partial settlement is punishing, and recovering less than 12.44% of the total owed would leave the exercise worse than writing it off.
How this is calculated
Interest is simple, not compounding: the invoice amount multiplied by the annual rate, divided by 365, multiplied by the days overdue. The cost of your time is your hourly rate multiplied by the hours you expect to spend. Agency commission, where that route is chosen, is a percentage of the amount actually recovered, so it falls when recovery is partial. The Disputes Tribunal filing fee is a fixed amount set by the size of the claim: $62 under $2,000, $124 from $2,000 to under $5,000, $248 from $5,000 to $30,000, and $496 from $30,001 to $60,000. Net recovery is the total owed less every cost. Break-even hours is the total owed less the non-time costs, divided by your hourly rate. The minimum worthwhile recovery is the fixed costs expressed as a share of the total owed.
Related NZ calculators
- Late Payment Cost Calculator for what late payment costs across a year
- Sole Trader Debtor Days Calculator to measure your collection speed
- Payment Terms Comparison Calculator for the terms that caused it
- Cash Runway Calculator for how long you last while it stays unpaid
- Self-Employed Emergency Fund Calculator for surviving the gap