Compound interest calculator
See how your balance grows with a starting amount, a gain per period and regular contributions — as a chart and a table.
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From numbers to practice
In the app you can save the scenarios you use often and reopen them in one click.
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What it calculates
Shows how your balance grows when you reinvest the profit from every trade. Each period the balance grows, so the next gain is calculated on a larger amount — growth accelerates rather than staying linear.
Formula
Each period: Balance = Balance × (1 + Gain%) + Contribution Without contributions: Final = Start × (1 + Gain%)^Periods
Example
Given
- Starting balance — $1000
- Gain per period — 2%
- Periods — 30
- Contribution — $0
- Period 1: $1000 × 1.02 = $1020 (profit $20).
- Period 2: $1020 × 1.02 = $1040.40 (profit $20.40 — already more).
- …
- Period 30: $1000 × 1.02^30 = $1811.36.
- Net profit: $811.36. With simple interest it would be only $600.
Result: After 30 periods: $1811.36 — that's 1.81× and +81% ROI.
Tip
Small percentages compound into large results over time — but it cuts both ways: losses compound too. Save your frequent scenarios as presets.
Frequently asked questions
- How is compound interest different from simple interest?
- Each period's gain is added to the principal and earns gains itself. $1000 growing 2% for 30 periods becomes $1811; with simple interest it would be only $1600.
- What is a period?
- Any unit — a trade, a month or a year. Enter the gain percent for that same period.
- How are regular contributions handled?
- They are added at the end of each period: Balance = Balance × (1 + gain%) + contribution.
Further reading
- A halal portfolio for beginners: 5 stepsWe won't tell you which stocks to buy — that's your call. The process for building and keeping a halal portfolio: screening, diversification, purification and re-checks.
- Dividends, zakat and tax: a practical guide for US stock holdersHow much US tax is withheld from dividends, what to declare in Uzbekistan, and how zakat on shares is calculated — with one worked example.
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