CalcKit

Compound Interest Calculator

See how interest and regular contributions grow over time.

Enter your values

Starting balance before new contributions.

Fixed nominal annual rate.

Whole years to project.

Contributions are made at the end of each chosen period.

Amount deposited after each compounding period.

Result

Future balance$18,207.33
Initial investment
$1,000.00
Added contributions
$12,000.00
Interest earned
$5,207.33

Interest compounds at your chosen frequency, with contributions added at the end of each period. The rate stays constant; taxes, fees and inflation are excluded.

Calculated in your browser. Share links include the values you choose to share.

For general information and mathematical estimates. Results are not financial, investment or tax advice.

Formula

FV = P(1 + r/n)^(nt) + C × [(1 + r/n)^(nt) − 1] ÷ (r/n). At 0%: FV = P + Cnt.

Worked example

$1,000 initially, 6% annual interest, monthly compounding and $100 per month for 10 years.

Future balance is $18,207.33, including $12,000 in deposits and $5,207.33 in interest.

How to use

  1. Enter your starting balance, annual rate and years.
  2. Select how often interest compounds and enter the contribution for each such period.
  3. Calculate the projected balance. In the formula, P is principal, r is annual rate as a decimal, n is periods per year, t is years and C is contribution per period.

Related calculators

SavingsProject your balance with monthly deposits and compound interest.Investment ReturnCompare total return with the annualized growth of an investment.Percentage ChangeMeasure the percentage increase or decrease between two values.

Frequently asked questions

Is the contribution always monthly?

No. It matches the selected compounding frequency. A contribution of $100 with quarterly compounding means four $100 contributions per year.

What does compounding mean?

Previously earned interest also earns interest. More frequent compounding changes the effective annual yield when the nominal annual rate stays the same.

Does daily compounding count leap days?

This model uses a fixed 365 periods per year, not a calendar-day schedule. It is a projection rather than a bank statement reconciliation.