Finance

Interest Rate Calculator

Find the annual interest rate needed to grow a principal into a target future value — with monthly, daily and continuous compounding equivalents.

Effective annual interest rate
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Nominal rate for selected frequency
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Total interest earned
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Growth multiple (FV / PV)
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Doubling time
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Rule of 72 estimate
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Compounding formula: FV = PV · (1 + r/m)m·t  ⇒  r = m · [ (FV/PV)1/(m·t) − 1 ].
Continuous: FV = PV · er·t  ⇒  r = ln(FV/PV) / t.
The effective annual rate always equals (1 + r/m)m − 1 regardless of the time horizon.

Solve for r

Work backwards from a future value to the interest rate that produces it.

Any compounding period

Annual, quarterly, monthly, daily or continuous — all converted to an EAR.

Doubling time

See how fast money doubles at the found rate, verified against the Rule of 72.

Investment targets

Great for ROI, savings goals and comparing returns across assets.

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