NSW Post Judgment Interest Calculator

The NSW post-judgment interest calculator works out the interest that accrues on a court judgment debt in New South Wales from the date of judgment until the date it is paid. You enter the judgment amount, the judgment date, the expected payment date, and the applicable interest rate, and it returns the total interest owed plus the total amount payable. The calculation follows the rules in the Civil Procedure Act 2005 (NSW) and the Civil Procedure Regulation 2017, which set a prescribed rate that changes periodically.

Formula

The formula for post-judgment interest in NSW is straightforward:

Interest = Principal × Annual Rate × (Days / 365)

Where:

• Principal – the judgment debt amount, in dollars (including any costs ordered if they are part of the judgment).
• Annual Rate – the prescribed post-judgment interest rate expressed as a decimal (e.g., 8.25% becomes 0.0825).
• Days – the number of days from the judgment date to the payment date, inclusive of the start date and exclusive of the payment date (the standard convention for court interest).
• 365 – the year length used by NSW courts for interest calculations, regardless of leap years.

The result is the interest in dollars, rounded to the nearest cent. The total payable is the principal plus that interest.

Worked Example

Using the default values in the calculator:

• Principal = $50,000
• Annual rate = 8.25%
• Judgment date = 2024-01-15
• Payment date = 2025-01-15

Step 1: Calculate the number of days between the dates. From 15 January 2024 to 15 January 2025 is exactly 366 days (2024 is a leap year, so February has 29 days).

Step 2: Convert the percentage rate to a decimal: 8.25% = 0.0825.

Step 3: Apply the formula:

Interest = 50,000 × 0.0825 × (366 / 365) = 50,000 × 0.0825 × 1.0027397 = 4,136.30 (rounded).

Step 4: Total payable = 50,000 + 4,136.30 = $54,136.30.

The calculator gives the same result because it uses the exact same formula with the same inputs.

How the NSW Post-Judgment Interest Rate Is Set

Under the Civil Procedure Act 2005 (section 101), a judgment debt carries interest at the prescribed rate, which is set by the Civil Procedure Regulation 2017. The rate is not fixed; it changes over time. Historically, it has been set at the 10-year Australian Government bond yield plus a margin (currently 4% as of the 2017 regulation, though the exact margin and formula have varied). The current rate is published on the NSW legislation website and in practice is updated periodically, often annually or when the bond yield changes significantly.

To use the calculator accurately, you must know the rate that applies on the day of judgment. If the rate changed during the period between judgment and payment, you would need to calculate interest in segments, each with its own rate. This calculator assumes a single constant rate, which is correct for most cases where the rate has not changed during the period.

When Post-Judgment Interest Applies

Post-judgment interest applies to any money judgment in a NSW court, including the District Court, Supreme Court, and Local Court (for amounts over its jurisdictional limit). It starts accruing from the date of judgment, not from the date the cause of action arose (that is pre-judgment interest, which is different). The interest runs until the judgment is satisfied, meaning the full amount is paid.

There are exceptions and nuances:

• If the judgment includes an order for costs, those costs also attract interest from the date they are assessed or agreed, not from the judgment date.
• If the judgment is paid in instalments, interest is calculated on the outstanding balance after each payment.
• If the judgment is stayed (paused), interest may not run during the stay, depending on the court’s order.
• For judgments in a currency other than AUD, the interest rate may be the rate applicable in that currency’s jurisdiction, not the NSW rate.

How to Use the Calculator Correctly

To get an accurate estimate, follow these steps:

1. Determine the exact judgment amount, including any costs that are part of the judgment order.
2. Find the prescribed post-judgment interest rate that was in effect on the judgment date. Check the NSW legislation website or the court’s registry if unsure.
3. Enter the judgment date and the expected payment date. The calculator counts the days between them inclusive of the start date.
4. If the rate changed during the period, run the calculator separately for each rate segment and add the results.
5. If partial payments have been made, calculate interest on the reducing balance manually or adjust the principal input for each segment.

The result is an estimate. For enforcement purposes, the court or a sheriff will calculate the exact figure, but this tool helps you plan or negotiate.

Common Mistakes and Misconceptions

• Using the wrong rate: The rate is not the same as the contractual interest rate in the original agreement. It is the statutory rate set by the regulation.
• Counting days incorrectly: Courts typically count from the judgment date to the day before payment. If you pay on the judgment date itself, no interest is owed.
• Ignoring leap years: The formula uses 365 days for the year, not 366, even in a leap year. The number of days in the period is the actual calendar days, but the denominator stays 365.
• Assuming the rate is fixed: The rate changes. If the judgment is over a year old, the rate may have changed multiple times.
• Forgetting costs: Costs awarded as part of the judgment also earn interest, but only from the date they are quantified.

Alternatives and Related Calculations

If you need to calculate pre-judgment interest (interest from the date the debt arose to the date of judgment), that is a different calculation, often based on the contractual rate or the court’s discretion under section 100 of the Civil Procedure Act. This calculator does not handle pre-judgment interest.

For debts that are not judgments, the interest rate is usually set by the contract or by statute (e.g., the Interest on Debts Act for certain debts). This calculator is specifically for post-judgment interest under NSW law.

If you are dealing with a federal court judgment, the rules are different (under the Federal Court Act 1976), and the rate is set by the Federal Court. This calculator is not applicable there.

Frequently Asked Questions

What is the current post-judgment interest rate in NSW?

The rate is set by the Civil Procedure Regulation 2017 and is updated periodically. As of recent years, it has been around 8-10%, but you must check the current regulation or the NSW legislation website for the exact figure on your judgment date. The rate is not a fixed number; it changes with the bond market.

Does interest accrue on costs?

Yes, but only after the costs have been assessed or agreed. From that date, the costs amount carries interest at the same prescribed rate. Before assessment, no interest accrues on costs.

Can I use this calculator for a Local Court judgment?

Yes, the same statutory rate applies to Local Court judgments. However, the Local Court has a jurisdictional limit (currently $100,000 for most claims), so the principal amount will be within that range.

What if the judgment is paid in instalments?

You must recalculate interest on the reducing balance. For each payment, reduce the principal by the payment amount, then calculate interest on the remaining balance for the next period. This calculator assumes a single lump-sum payment, so you would need to run it multiple times or adjust manually.

Is the interest compounded?

No. Post-judgment interest is simple interest, not compound. It is calculated on the original judgment amount (or the outstanding balance) only, not on previously accrued interest.

What if the judgment is in a foreign currency?

For judgments in a foreign currency, the interest rate is generally the rate applicable in that currency’s country, not the NSW rate. The court will specify the rate in the judgment. This calculator only works for AUD judgments using the NSW prescribed rate.

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in p | Principal judgment amount | $ | 50000 | 0 | 10000000
in r | Annual interest rate (e.g. 8.25) | % | 8.25 | 0 | 100
in d1 | Judgment date (YYYY-MM-DD) | - | 2024-01-15 | 2000-01-01 | 2100-12-31
in d2 | Payment date (YYYY-MM-DD) | - | 2025-01-15 | 2000-01-01 | 2100-12-31
out interest | Interest amount | $ | p * (r/100) * (d2 - d1) / 365 | 2
out total | Total payable | $ | p + p * (r/100) * (d2 - d1) / 365 | 2