Sinking-fund factor

Compute annual contribution needed for a target future value and sinking-fund factor table.

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Calculation specification

Reviewed on:

Formula basis

The sinking fund factor is r/{(1+r)^n−1}, or 1/n when r=0. Required annual contribution equals target times the factor.

Calculation method

Calculates the fixed year-end contribution required to accumulate a future target using the sinking fund factor.

Exclusions and checks required

  • Contributions occur at year-end under a constant rate and annual compounding; tax and fees are excluded.
  • A known implementation limitation rounds the factor to six digits regardless of the digits control, so other selected values do not affect the result.

Example input:：Building JPY 30 million over 20 years at 3%

targetMan
3000
annualRate
3
years
20
digits
6
rounding
halfUp

The required amount uses year-end fixed contributions and the current six-digit factor display.

FAQ

Who is this calculator for? Sinking-fund factor

Compute annual contribution needed for a target future value and sinking-fund factor table.

What values should I enter?

Applies to: Savings factors / Sinking-fund factor = r ÷ {(1+r)^n − 1}

How should I interpret this estimate?

Calculates the fixed year-end contribution required to accumulate a future target using the sinking fund factor.

How to use

  1. Enter your input values and press Calculate.
  2. Review the result and compare it with expected context.
  3. The sinking fund factor is r/{(1+r)^n−1}, or 1/n when r=0. Required annual contribution equals target times the factor.