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Future value calculator

A starting amount, a regular contribution, a rate, and time. The formula is verified against a month-by-month simulation, and contribution timing - start or end of each period - is handled properly, because it changes the answer.

NPV & IRRXIRR (dates)IRR ↔ MOICReal estate IRRFuture value
Expected annual growth. Diversified shares have averaged 7–10% before inflation over long periods; savings accounts far less. Past averages are not guarantees.
How often the account actually credits interest - not always the same as how often you contribute. Most savings and brokerage accounts compound monthly; some term products compound quarterly or yearly.
Start-of-period contributions earn one extra period of growth each – over decades it adds up.
Set a target instead of a contribution amount, and this works out the contribution per period that gets you there.

How is the worked example verified?

$10,000 up front plus $500 a month at 7% for 20 years, compounding monthly, grows to $300,850.72 with end-of-month contributions - a figure this page's month-by-month simulation reproduces and an independent closed-form annuity formula confirms to the cent. Of that, $130,000 is money you put in; the other $170,850.72 is compounding. Move the contributions to the start of each month and the total rises to $302,370.09, because every deposit gets one extra month of growth - timing is small per deposit and real in aggregate. Switch compounding to quarterly instead, keeping contributions monthly, and the same inputs land at $300,761.05 - a little lower, because deposits now sit for a few weeks before the next compounding date actually credits them.

What does this calculator assume?

Contribution frequency and compounding frequency can be set independently and the page simulates the difference month by month rather than assuming they match - a monthly deposit into a quarterly-compounding account earns nothing on that deposit until the next quarter's compounding date, the way a real statement would show it. The rate is constant, and nothing is taken out for tax, fees, or inflation, so treat the output as the mechanical ceiling, not a forecast. For how a bank actually credits savings interest daily with bonus-rate conditions, the savings account calculator models that specifically.

For general information and education only. This page shows the mathematics of the numbers you enter - it does not know your circumstances, tax position, or appetite for risk, and nothing here is financial, investment, tax, or legal advice. For decisions that matter, check the figures against your own documents and talk them through with a qualified adviser.

Common questions

How is future value calculated?

The starting amount grows by compound interest, and each contribution grows from the moment it lands, simulated month by month rather than a single formula - because contribution frequency and compounding frequency can be different (a monthly contribution into a quarterly-compounding account, for instance), and the page states whether contributions land at the start or end of each period, because that changes the answer too.

Is future value guaranteed?

No. The rate you enter is an assumption, and for anything market-based the real path will wobble around it. Long-run averages are a planning tool, not a promise - run a low and a high rate and treat the range as the honest answer.

How much do I need to contribute to hit a target amount?

Enter the target in the "target future value" field instead of a contribution amount, and the page solves backwards for the contribution per period that gets you there exactly, given your starting amount, rate, compounding, and timeframe.

What is the difference between future value and present value?

Future value asks what a sum today, plus contributions, grows into by a future date. Present value asks the reverse: what a future sum is worth today, discounted back. They are mirror-image calculations built on the same compound interest math, just solving for opposite ends of the timeline.

Does compounding frequency matter as much as the interest rate?

The rate matters far more over any meaningful timeframe - the gap between monthly and daily compounding at the same rate is small, while the gap between two different rates compounds into a large difference over decades. Compounding frequency is worth getting right for precision, but it is not where the real leverage in a long-term projection comes from.