Late Settlement Interest Calculator NZ
Settlements run late for ordinary reasons. A bank does not release funds in time, a transfer misses a cut-off, a chain of related sales slips by a day and everything behind it slips too. What surprises people is that being late is not a neutral administrative event but a breach of contract with a price attached, charged daily, at a rate chosen precisely because it is uncomfortable. The other thing that surprises people is that the arrangement is not symmetrical. Default interest runs on money the purchaser owes and has not paid, so a purchaser who is late pays and a vendor who is late generally does not, and the purchaser instead has to prove actual losses. Knowing which side of that you are on determines whether you are calculating a number or assembling receipts.
The calculation
What each further day adds
| If settlement is | Default interest | With costs |
|---|---|---|
| 1 day late | $236.71 | $736.71 |
| 3 days late | $710.14 | $1,210.14 |
| 5 days late | $1,183.56 | $1,683.56 |
| 10 days late | $2,367.12 | $2,867.12 |
| 20 days late | $4,734.25 | $5,234.25 |
Interest accrues on calendar days, including weekends and public holidays, even though settlement itself can only happen on a working day.
The two sides are not treated the same
| If the delay is caused by | What the other party gets | How it is proved |
|---|---|---|
| The purchaser | Default interest on the unpaid balance, plus reasonable costs caused by the delay | Arithmetic. The rate is in the agreement and the balance is known |
| The vendor | Generally no default interest, because there is no unpaid balance running against them. The purchaser claims their actual loss instead | Receipts. Accommodation, storage, rebooked removals and extra finance costs have to be real and evidenced |
On these figures a late purchaser owes $2,867.12 as a calculation. A purchaser delayed by the vendor for the same 10 days would be claiming $500.00 of documented costs, and nothing for the inconvenience.
The rate is chosen to hurt
Default interest rates in sale and purchase agreements sit far above what anyone would pay to borrow the same money, and that is deliberate. The clause is not there to compensate the vendor for the time value of a few days, which would be a much smaller number. It is there to make sure that settling on time is always cheaper than not settling on time, so that a purchaser with a choice about where to direct their attention directs it here. On any ordinary New Zealand purchase the daily figure runs to a couple of hundred dollars, which is enough to make a week of drift expensive and a month of it serious.
Interest runs on the balance, not the price
A common miscalculation is to apply the default rate to the whole purchase price. It runs on what remains unpaid, which is the price less the deposit already handed over on signing. On a ten per cent deposit that difference reduces the daily figure by a tenth, which is not enormous but is worth getting right if the delay runs on. Where a purchaser has paid a larger deposit the effect is correspondingly bigger.
A late vendor is a different problem entirely
The asymmetry catches people out because it feels unfair, and understanding why it exists makes it easier to deal with. Default interest is a charge on money owed and not paid. When the vendor causes the delay there is no such money, because the purchaser has not failed to pay anything, so there is nothing for interest to run on. What the purchaser has instead is a claim for the loss the delay actually caused them, which is a completely different exercise: it needs evidence, it covers only real expenditure, and it compensates nothing for the disruption of having a truck full of furniture and nowhere to put it. Purchasers in that position should keep every receipt from the moment the delay is known.
Worked example
A purchase at $800,000.00 with $80,000.00 already paid leaves $720,000.00 unpaid. The agreement specifies default interest at 12.00% a year, so the daily rate is $236.71.
The purchaser settles 10 days late, so default interest is $2,367.12. The vendor also incurred $500.00 of costs because of the delay, bringing the total to $2,867.12.
Had the same delay been caused by the vendor, no default interest would run, because the purchaser has not failed to pay anything. The purchaser would instead be claiming the $500.00 of documented costs the delay caused them, and would need the receipts.
How this is calculated
The unpaid balance is the purchase price less the deposit already paid. The daily interest is that balance multiplied by the annual default rate and divided by 365, and the total interest is the daily figure multiplied by the number of calendar days late, including weekends and public holidays. Costs caused by the delay are added on top rather than being part of the interest calculation, since they are a separate head of claim. Where the vendor is the party causing the delay the interest is not charged at all, and the result shows only the documented costs, because there is no unpaid balance for interest to run against.
Official sources
- Buying and selling property, New Zealand Law Society
- Settlement and moving in, settled.govt.nz
- Contract and Commercial Law Act 2017, legislation.govt.nz
Related NZ calculators
- Settlement Funds Shortfall Calculator for avoiding the delay in the first place
- Settlement Apportionment Calculator for the outgoings adjustment
- Deposit at Risk Calculator if the delay becomes a failure to settle
- Bridging Loan Calculator if the delay is in a chain of sales
- Early Possession and Rent-Back Calculator for the other way dates get rearranged
Related calculators
- Property Legal Fees Calculator NZ: conveyancing and LINZ Costs.
- Pre-Settlement Inspection Defects Calculator NZ: What You Can Claim.
- Private Sale vs Agent Calculator NZ 2026: What You Actually Keep.
- Real Estate Agent Commission Split Calculator NZ 2026/27: what a salesperson actually keeps.