Future Value Calculator with Contributions

Enter Calculation

Initial Investment

Periodic Contribution

Annual Interest Rate (%)

Years

Contribution / Compounding Frequency Monthly Quarterly Annually

Contribution Timing End of period Beginning of period

Results

Future Value

125,510.22

total balance at the end

Total contributions paid in	48,000
Total of all money invested	58,000
Total interest earned	67,510.22

What this calculator does

This Future Value Calculator projects how much an investment will grow over time when you start with an initial lump sum and add regular contributions. It applies compound interest at the frequency you choose — monthly, quarterly, or annually — and supports contributions made at either the end or the beginning of each period.

Future value combines the initial principal, regular contributions and compound interest growth over time.

How to use it

Enter your initial investment, the amount you contribute each period, the annual interest rate, and the number of years. Pick how often interest compounds and contributions are made, then choose whether contributions happen at the end or beginning of each period. The result shows the projected future value, the total you paid in, and the interest earned.

The formula explained

The future value combines two parts: the growth of the initial principal and the growth of an annuity stream of contributions:

$$FV = P(1+i)^n + C\left[\frac{(1+i)^n - 1}{i}\right]$$

Here \(P\) is the initial principal, \(C\) is the contribution per period, \(i = r/m\) is the periodic interest rate, and \(n = m \times t\) is the total number of periods. For contributions made at the start of each period, the annuity term is multiplied by \((1+i)\).

The formula adds the grown initial principal to the accumulated value of all contributions.

Worked example

Start with \(P = 10{,}000\), contribute \(C = 200\) monthly, at \(r = 6\%\) for \(t = 20\) years, end-of-period. Then \(i = 0.06/12 = 0.005\) and \(n = 240\).

$$(1.005)^{240} \approx 3.310204$$ $$FV = 10000 \times 3.310204 + 200 \times \frac{3.310204 - 1}{0.005}$$ $$FV \approx 33102.04 + 92408.16 = 125510.22$$

Total contributions are \(200 \times 240 = 48{,}000\), so interest earned is about \(67{,}510\).

FAQ

Does compounding frequency match contribution frequency? Yes — this tool assumes contributions are made every compounding period, which is the standard annuity model.

What is the difference between end and beginning timing? Beginning-of-period contributions earn one extra period of interest, so they grow slightly more.

Is the rate nominal or effective? The rate you enter is the annual nominal rate, divided evenly across the periods you choose.