Interest Rate Calculator
Work backwards from the amount you want to reach.
Rate Details
Required Annual Interest Rate
How to use this calculator
You know how much you have today and how much you want it to grow to. The calculator finds the annual interest rate needed to get there over your time period. Use it to compare what rate a deposit is really paying, or to set realistic investment return expectations.
Interest Rate FAQ
On this page
Interest Rate Calculator — what rate turns your principal into a target?
Working forwards is easy; working backwards is powerful. Enter the principal, the target maturity amount and the time horizon, and this calculator reveals the exact interest rate you need — with proper compounding — to hit your goal.
The reverse compound formula
Rate = n × [(Maturity ÷ Principal)^(1/(n×years)) − 1] × 100, where n is the compounding frequency per year.
To grow $5,00,000 to $10,00,000 in 8 years, you need about 9.05% annual compounding — a rate achievable with a balanced equity fund but not with an FD.
Compounding frequency slightly changes the required nominal rate: quarterly compounding needs a lower nominal rate than annual.
Realistic rate expectations
FD / debt funds: 5–8% | Balanced funds: 7–9% | Equity funds: 10–14% (long-term).
If the required rate exceeds what's realistic, extend the horizon or increase contributions — the calculator makes the trade-off visible.
A shorter horizon and a fat target may force defensive assets, reducing risk — sometimes the wisest adjustment.
How to use this calculator
- Enter the current principal amount.
- Enter the target maturity amount.
- Set the number of years.
- Select the compounding frequency.
- Read the required annual rate and total interest.
Pro tips
- Use this to sanity-check 'guaranteed return' schemes — an unrealistic required rate is a red flag.
- Conservative plan: always assume the lower realistic rate for goal planning.
- Compare the required rate against current FD and equity expectations before committing.