📈 CALCULATOR · 03 / 04
Interest Calculator
See what your money can become. Time in the market beats timing the market.
Compounded monthly · results update as you type
Final balance
Money multiplied 11.3×
ⓘ How we calculate
FV = P(1+r/n)^(nt) + PMT × [((1+r/n)^(nt) − 1) / (r/n)]. Compounded monthly.
How to use the interest calculator
1. Enter the starting balance
The amount you plan to deposit or the balance you already hold. This is the base the calculator grows.
2. Set the interest rate and period
Use the annual rate your bank or product states, then choose how long the money stays. The calculator shows growth over the full period.
3. Understand the two types of interest
Simple interest pays on the original amount only. Compound interest pays on the original plus what it has already earned — which is why balances accelerate over time.
Worked example
Rp 10,000,000 at 5% simple interest earns Rp 500,000 in the first year. Under compounding, year two earns 5% on Rp 10,500,000 — Rp 525,000 — so the balance grows faster the longer it stays invested. Over five years the difference compounds into a meaningful gap, which is why time in the market matters more than timing the market.
Common mistakes
Confusing simple and compound interest
Many savings products use compound interest but quote it annually. Ask whether interest is credited monthly or yearly — monthly crediting grows the balance faster.
Ignoring fees
A tiny annual fee can erase several percentage points of growth over a decade. Run the numbers after fees, not before them.
Treating projected growth as guaranteed
Interest rates change and some products are variable. Use the calculator to compare scenarios, then confirm the current rate before you commit.
Frequently asked questions
What is the difference between simple and compound interest?
Simple interest is calculated on the original amount only. Compound interest is calculated on the original amount plus everything it has already earned, so growth accelerates over time.
Does it matter how often interest is applied?
Yes. The more often interest is credited — monthly versus yearly — the faster the balance compounds, even at the same annual rate.
Is this a guarantee of returns?
No. The calculator models a fixed rate for illustration. Actual rates fluctuate, so treat the projection as a direction, not a promise.
This calculator is for illustration only and does not constitute financial advice. Interest rates, fees, and product terms vary — confirm the current details with your bank or provider.
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