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Savings interest rate calculator

Recover the constant annual saving rate required to reach a goal.

Calculator

A model year is 365.25 days; a month is one twelfth of that year.

Nominal annual rate
-58.4632%
Effective annual return
-45.0833%
Return per cash flow interval
-4.8719%
Real annual return
-46.1601%
Net contributions
$6,000.00
Projection end date
2031-04-01
Balance projection
YearsBalance ($)
0.00001,000.0000
1.00001,474.5356
2.00001,735.1347
3.00001,878.2471
4.00001,956.8396
5.00002,000.0000

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How this calculator works

A numerical search finds the annual growth factor that matches your final goal. Contributions occur at the chosen interval, at the beginning or end of each period. Only completed end periods are paid; beginning payments include the opening of a partial period. The displayed nominal rate uses your compounding frequency. This fixed-rate model ignores tax, charges and irregular cash flows.

Formula

Final = initial x exp(Lt) + sum of signed cash flows x exp(L x remaining years). Effective annual return = exp(L) - 1. Nominal rate = m[exp(L/m) - 1]; continuous nominal rate = L.

Worked example

With no cash flows, $1,000 growing to $1,210 over two years needs a 10% effective annual return. With $100 added at each year end for two years, $1,000 becomes $1,420 at 10%.

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Frequently asked questions

Are deposits counted as investment gains?

No. The solver explicitly includes contributions when determining the required return.

Does frequency affect the effective return?

The compounding frequency changes the nominal quote; the effective return describes the same annual growth factor.

Is the result a forecast?

It is the constant mathematical rate implied by your assumptions. Actual market or savings returns may vary.

Sources

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