Finance calculators

Savings goal calculator

The regular saving needed to reach a target, with interest earned and a year-by-year path.

Inputs

Savings goalCurrent savingsInterest rate%Time to goalyearsSaveSaved at

Results

Methodology

Conventions

Interest compounds at the contribution frequency p, at the nominal rate r.
Current savings grow over the whole period; level contributions make up the rest of the goal.

References

Kellison, The Theory of Interest, ch. 3 and 5

Formulas

Periodic rate: i = r/p,\quad n = p \cdot t
Contribution needed: C = \frac{G - S (1 + i)^n}{\frac{(1 + i)^n - 1}{i} (1 + i)^{\delta}}

If current savings already grow to the goal, no contribution is needed.