About this tool
The Savings Calculator shows what a deposit grows to when you add money every month and the bank compounds the interest monthly. Enter a starting balance, a monthly contribution, a rate and a period in months or years, and the page returns the future balance, the total you paid in and the interest earned, with a chart that splits the final figure into your opening deposit, your contributions and the interest. It is built for the saving people actually do in Cambodia: a teacher putting aside part of a salary each month for a moto, a family building a deposit for a Borey unit, a worker keeping riel and dollars side by side, or anyone checking whether a bank's advertised rate makes a real difference over five years. It assumes the rate stays fixed for the whole period, that interest is credited monthly, and that you never withdraw. It does not know what any bank pays, does not include fees, withholding tax, minimum-balance rules or inflation, and does not model a fixed-term deposit with a penalty for early withdrawal. It is a projection, not a promise, and not financial advice.
How it works
The arithmetic is `futureValue` in `savings-calculator-client.tsx`: the annual rate is divided by 12, the period is converted to months, and the balance is FV = P × (1+r)ⁿ + PMT × ((1+r)ⁿ − 1) ÷ r, where P is the opening balance, PMT the monthly contribution, r the monthly rate and n the number of months. That is the closed form of adding the contribution at the end of each month and compounding the whole balance monthly, so a contribution made in the first month earns interest for every remaining month and the last one earns nothing. At a 0% rate the formula reduces to the opening balance plus the contributions, which is why the interest line reads zero. The results panel shows the future balance, the total contributions and the interest earned, which is the balance minus the opening amount minus the contributions, and the chart colours those three parts. Amounts are rounded only for display — riel to whole numbers, dollars to two decimals. The form rejects a negative opening balance or contribution, a period outside 1 to 600 months or 1 to 50 years and a rate outside 0 to 100%, and shows a message instead of a result. The currency selector changes the symbol and the decimals only, not the arithmetic. The rate field opens at 1.3%, which is a starting value coded into the page and not a quote from any bank.
Use cases
- A teacher setting aside 300,000 riel a month towards a moto and checking the balance after three years
- A family building the down payment for a Borey unit and testing a five-year plan against a seven-year one
- A worker comparing a 3% deposit account against a 5% one on the same monthly contribution
- A student projecting what a scholarship instalment plus family support will be worth at graduation
- A couple checking how much of the final balance is their own money and how much is interest
- A saver testing whether starting with 1,000 dollars now beats adding it over two years
- A trainer showing why a 1% difference in the rate matters far less than the amount saved each month
Frequently asked questions
Is the rate on this page a bank rate?
No. It is a number you type, and the form opens at 1.3% only so the chart has something to draw. That starting value is coded into the page and is not a quote from any bank, is not kept up to date and is not an average of the market. Replace it with the rate in your deposit agreement or the rate the bank quoted you in writing, and remember that a promotional rate often applies for a few months before it resets.
How does the calculator compound interest?
Monthly, with the contribution added at the end of each month. The annual rate is divided by twelve and applied to the whole balance every month, so interest earns interest from the second month onward. A bank that compounds quarterly, or that credits interest only at maturity, will produce a slightly different balance for the same nominal rate. If your account pays simple interest or credits annually, treat this figure as the optimistic end of the range.
Why is my real balance lower than the projection?
Four common reasons. Withholding tax on deposit interest is deducted before the interest reaches your account and is not modelled here. Monthly or annual account fees and minimum-balance penalties are not modelled either. A promotional rate that resets after six or twelve months means the average rate over the term is lower than the one you typed. And if you miss a monthly contribution, the plan compounds a smaller balance for the rest of the period.
Can I model a withdrawal or a lump sum partway through?
No. The model has one opening balance, one constant monthly contribution and one rate, and it assumes nothing is taken out until the end. A withdrawal resets the balance and loses all the interest that amount would have earned, which is usually much more than the amount itself by the end of a long period. To approximate a mid-term withdrawal, run two calculations — one for the period before it and one starting from the reduced balance for the remainder.
What about inflation and exchange rates?
Neither is modelled. The result is in nominal terms, so a balance of 13,946,000 riel in ten years buys less than the same number today, and the page does not adjust for that. It also does not convert between riel and dollars: the currency selector is a display setting, so a riel plan and a dollar plan are separate calculations and the exchange rate between them over the term is an extra risk this page cannot price.
Should I save in riel or in dollars?
The calculator cannot answer that, because the choice depends on the rate each bank offers, on how you will spend the money and on what happens to the exchange rate. What it can do is show the arithmetic: run the same plan in both currencies at the rates you are actually offered and compare the two balances, then decide how much of the difference is compensation for currency risk. This page takes no position and holds no view on the rate.
Is this projection guaranteed, and is it advice?
No. It is arithmetic on the numbers you entered, assuming a fixed rate and no withdrawals, and it has no connection to any bank, product or regulator. It does not know whether the institution is licensed, what happens if it fails, or what the terms of your particular account are. Treat the result as a planning figure and confirm the actual terms, including any protection that applies to deposits, with the bank and the National Bank of Cambodia before you commit money.
Why does a small change in the rate barely move the result?
Because with a monthly contribution the balance is dominated by what you pay in, not by what it earns. A plan with 1,000 dollars to start and 200 dollars a month for five years pays in 13,000 dollars: at 5% the interest adds 1,885 dollars and at 3% it adds 1,091, so two percentage points are worth 794 dollars over five years. Raising the monthly amount to 250 dollars at the same 5% adds 3,000 dollars of contributions and 400 dollars of extra interest. That is the useful conclusion of most runs of this page, and it is why the contribution field matters more than the rate field.
Data and accuracy
Nothing is fetched and no rate is built in beyond the 1.3% starting value in the form. The calculation is `futureValue` in `savings-calculator-client.tsx`, the closed form of a monthly-compounded deposit with a constant end-of-month contribution. The page holds no bank rate table and does not read deposit products from any institution; banks and deposit-taking institutions in Cambodia operate under the supervision of the National Bank of Cambodia, but this page reads nothing from it. Content reviewed on 21 October 2026.
Sources
- National Bank of Cambodia — official site of the banking and financial institution supervisor — National Bank of Cambodia
Content last reviewed 21 October 2026