Disclaimer
The results obtained from these calculators are for general purposes only to illustrate the effect of compound interest and are not intended as a substitute for professional financial advice. Before making any financial decisions on the basis of these results, you will need to consult with an independent financial planner or accountant as well as consider whether the advice is suitable to meet your personal financial objectives and circumstances.
The actual performance of any investments will depend on future economic conditions, investment management, fees and taxation. Past performance is no guarantee of future performance and as a result of this, all the results are hypothetical and are NOT GUARANTEED.
Nambawan Super specifically disclaims any liability for any direct, indirect, incidental, consequential or special damages arising out of or in any way connected with the access to or use of these calculators. To the extent permitted by law, under no circumstances will Nambawan Super be liable for any loss or damage caused by a user's reliance on the information by using these calculators.
Assumptions
Projected super balance at retirement:
The projected total super balance takes into account your starting balance, employee and employer contributions, any additional voluntary contributions as well as interest earned between now and your retirement.
Retirement age:
We have assumed a default retirement age of 65. This can be adjusted in the calculator.
Working life:
The calculator assumes that you will have a continuous working life with no breaks up to your retirement age.
Interest rate:
The default investment returns have been set at 6.0%. This is based on the Nambawan Super 10-year average interest rate.
Employee contributions:
PNG Superannuation laws dictate that 6% is the mandatory minimum contribution for employees to make. Employees may choose to contribute more than the minimum.
Employer contributions:
PNG Superannuation laws dictate that 8.4% is the mandatory minimum contribution that employers have to make. Employers may choose to contribute more than the minimum.
Most hardworking Papua New Guineans are unsure of how exactly their interest from the returns of the year are calculated and applied to their account. Superannuation interest on individual Member Accounts are not calculated using a straightforward formula of ‘Total Balance multiplied by Crediting Rate equals interest credited to a Member’s account’ Nambawan Super Limited (NSL) like other superfunds in Papua New Guinea use a formula called the Time-Weighted Rate of Return formula.
What is the Time-Weighted Rate of Return formula?
Using the Time-Weighted Rate of Return formula, Members interest is calculated based on when your contributions are received by Nambawan Super and how long they have been in your account.
If you think about it, only when Nambawan Super receives your savings, then they can invest
them to earn interest.
How does the Time-Weighted Rate of Return formula work?
To calculate interest, you need to understand how it applies on the two portions, your Opening Balance at the beginning of the financial year, and your Contributions made during the year.
1. Interest on Opening Balance
Your starting balance (the money in your account at the beginning of the year) earns interest for the whole year.
Interest on Opening Balance = Opening Balance x Annual Interest Rate
For example, if you start with K12,000 and the interest rate is 10.0% your balance will grow by K1,200 on the Opening Balance portion of your savings.
2. Interest on Contributions made during the year
Your Member contributions and Employer contributions made by your Employer on your behalf during the year also earn interest, but only for the time they have been with Nambawan Super during the year.
Interest on Contributions made during the year = Contribution Amount x (Number of Days remaining in the Year ÷ 365) x Annual Interest Rate
For example, for your contributions of K1,000 made on June 1, 2025, there are 213 Days remaining in the standard year.
3. Total Interest for the year
Add it all up – at the end of the year, you get the Interest on the Opening Balance, plus the time-weighted Interest on each Contribution made during the year.
Below is an example of how superfunds calculate the interest on a Members account using the Time-Weighted Rate of Return formula.
Let us assume that:
| Opening Balance (01/01/25) | K100,000 |
| Fortnight Member contributions (6%) | K90.00 |
| Fortnight Voluntary contributions | K20.00 |
| Fortnight Employer contributions (8.4%) | K126.00 |
| Annual Interest Rate | 12% |
Let's further assume the Member's Employer remit their contribution on the 1st day of each month.
Step 1: Interest on Opening Balance
| Annual Interest Rate | 12% |
| Opening Balance (at 01/01/25) | K100,000 |
| Interest on Opening Balance | K12,000 |
Step 2: Interest on Contributions made during the year
| Date | Days left in the year | Member Cont. | Member Voluntary Cont. | Employer Cont. | Total | Interest earned per month |
| 01/01/2025 | 364 | |||||
| 01/02/2025 | 333 | K270.00 | K60.00 | K378.00 | K708.00 | K77.51 |
| 01/03/2025 | 305 | K180.00 | K40.00 | K252.00 | K472.00 | K47.33 |
| 01/04/2025 | 274 | K180.00 | K40.00 | K252.00 | K472.00 | K42.52 |
| 01/05/2025 | 244 | K180.00 | K40.00 | K252.00 | K472.00 | K37.86 |
| 01/06/2025 | 213 | K180.00 | K40.00 | K252.00 | K472.00 | K33.05 |
| 01/07/2025 | 183 | K180.00 | K40.00 | K252.00 | K472.00 | K28.40 |
| 01/08/2025 | 152 | K180.00 | K40.00 | K252.00 | K472.00 | K23.59 |
| 01/09/2025 | 121 | K270.00 | K60.00 | K378.00 | K708.00 | K28.16 |
| 01/10/2025 | 91 | K180.00 | K40.00 | K252.00 | K472.00 | K14.12 |
| 01/11/2025 | 60 | K180.00 | K40.00 | K252.00 | K472.00 | K9.31 |
| 01/12/2025 | 30 | K180.00 | K40.00 | K252.00 | K472.00 | K4.66 |
| 31/12/2025 | 0 | K180.00 | K40.00 | K252.00 | K472.00 | K0.00 |
| Totals | K2,340.00 | K520.00 | K3,276.00 | K6,136.00 | K346.51 | |
| Interest on Contributions = K346.51 |
Step 3: Total Interest for the Year
| Interest on Opening Balance | K12,000.00 |
| Interest on Contributions | K346.51 |
| Overall Interest Earned | K12,346.51 |
NSL works closely with its Employers and the payroll officers to ensure contributions are promptly and periodically received, which then means that they earn more interest when the Financial Year ends, and the superannuation funds apply the Annual Interest from returns.
Read the full Crediting Rate Policy here.
