Investment Calculator

Project the future value of an investment with an initial amount, regular monthly contributions, and compound growth. Free, instant, no signup.

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years
Formula: FV = P(1+r)^n + C×((1+r)^n − 1)/r
  • P = initial investment
  • C = monthly contribution
  • r = monthly interest rate
  • n = total months

How to use the Investment Calculator

  1. Enter your values. Fill in the fields with your numbers.
  2. Calculate. Press Calculate to run the investment calculator.
  3. Use the result. Copy the result or try a related tool next.

Why use our Investment Calculator

Instant results. Enter your figures and the investment calculator returns an answer in seconds.
Free & private. Runs in your browser — no signup, and nothing is sent to a server.
Accurate. Uses standard formulas so you can rely on the numbers.

Free to use — premium coming soon

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About the Investment Calculator

The Investment Calculator projects how much a lump sum and ongoing deposits could grow over time once compound interest is applied. You enter a starting amount, an expected annual return rate, how often interest compounds, the length of the investment, and any recurring contribution. The tool then calculates the future value and separates it into three parts: the money you put in (principal plus deposits) and the interest those amounts earned. It is built for planning, not promising. Markets fluctuate year to year, so treat every figure as a smoothed estimate based on a constant return rather than a guaranteed outcome.

Reach for this calculator whenever you want to test a savings or investing idea before committing money. Common uses include estimating a retirement balance, sizing the monthly deposit needed to hit a house-deposit goal, comparing a one-off investment against drip-feeding the same cash over years, or seeing how an extra one or two percent of return changes the final number. Because you can vary a single input at a time, it is also a quick way to settle 'what if' debates: what if I start five years earlier, what if I add fifty more per month, what if returns are 5 percent instead of 8.

Under the hood the tool combines two standard finance formulas. A starting lump sum grows by FV = PV x (1 + r)^n, where r is the periodic rate and n is the number of periods. Recurring deposits use the future value of an annuity, FV = PMT x [((1 + r)^n - 1) / r]. The annual rate is divided by the compounding frequency to get r, and the years are multiplied by it to get n. Contributions made at the start of each period earn one extra period of growth versus end-of-period deposits, which is why the timing option noticeably shifts long-run totals.

Everything is calculated in your browser, so the amounts, rates, and goals you type are never uploaded, stored, or shared. The accuracy of the result depends entirely on your assumptions: a constant return, no skipped contributions, and no allowance for tax, platform fees, or inflation unless you bake those into the rate yourself. For a realistic view, run a conservative scenario alongside an optimistic one, and remember that historical averages, such as the roughly 9 to 10 percent long-run average of the S&P 500 before inflation, are not a forecast of any single year.

Frequently asked questions

What return rate should I enter?

Use a rate that matches the assets you hold. Diversified stock portfolios have historically averaged around 9 to 10 percent before inflation, balanced portfolios 6 to 7 percent, and bonds closer to 4 to 5 percent. For honest planning, subtract inflation and fees, or run both a cautious and an optimistic figure to see the range.

Does it matter if contributions are at the beginning or end of the period?

Yes. A deposit made at the start of each period earns one extra period of compounding compared with one made at the end. Over many years this 'annuity due' timing produces a meaningfully higher ending balance, especially at higher rates.

How does compounding frequency change the result?

The more often interest is added back, the sooner that interest starts earning its own interest. Monthly or daily compounding gives a slightly higher total than annual compounding at the same stated rate, though the difference is small compared with the impact of the rate itself and the time invested.

Does the calculator account for taxes, fees, or inflation?

No, not automatically. It models a clean, constant return. To reflect real conditions, lower your return rate to a net or 'real' figure, for example using 6 percent instead of 9 percent to roughly strip out inflation and platform costs.

Is my financial information saved anywhere?

No. The calculation runs entirely in your browser, so the amounts, rates, and goals you enter are not sent to a server, stored, or shared with anyone.

From our blog

How to Count Cash Fast and Accurately with the Money Counter

By the Super Simple Digital Tools Team · Updated June 2026

Counting cash by hand is slow and surprisingly error-prone, especially once coins enter the mix. The reliable method professionals use is to separate the work into two stages: physically organize the money first, then let a calculator do the arithmetic. The Money Counter is built for that second stage. Once your cash is sorted into clean stacks by denomination, the tool turns a row of quantities into an exact total, removing the mental addition that causes most mistakes during a busy shift or a quick deposit.

Start by sorting. Make one pile for each denomination you have, so all the twenties are together, all the quarters are together, and so on. Counting within a single denomination is far easier than counting a jumbled handful, because every item in the pile is worth the same amount. For bills, fan them face-up in the same direction; for coins, group them in tens so a glance tells you the count. This preparation is what makes the final number trustworthy, since the calculator can only be as right as the quantities you give it.

Next, enter the quantities. Type the number of bills or coins for each denomination into its matching field and leave the rest at zero. The tool multiplies each quantity by its face value behind the scenes, then adds the products together for a single total. Because the values are fixed, there is nothing to round and nothing to estimate. If you are working in a currency other than US dollars, switch to that currency so the denomination list matches the notes and coins you are actually holding.

If you are balancing a register, the total is only half the job. Compare it against what you expected: take your opening float, add the cash you took in, and subtract any cash paid out, then check that against the counted figure. A difference means either a miscount or a transaction error. Many businesses tolerate a small variance of a dollar or two, but anything larger is worth recounting before you write it off, because a single misread stack of bills can throw the whole drawer off.

Finally, treat the count as repeatable rather than a one-off. The same routine works for a piggy bank, a tip jar, a fundraiser collection, or a coin sorting session with kids, and it scales from a few dollars to a full till. Recounting the highest-value stacks once more before you commit the number is a habit worth keeping, since errors on hundreds and twenties move the total the most. With sorting done well, the Money Counter gives you a precise figure every time.

  • Sort into one stack per denomination before entering anything; counting within a single value is far less error-prone than counting a mixed handful.
  • Group coins in tens (ten dimes, ten quarters) so you can verify each stack at a glance and reduce miscounts.
  • When balancing a drawer, compare the total to opening float plus cash in minus cash out, and recount before treating any gap as a real shortage.
  • Always recount the high-value stacks like fifties and hundreds twice, since a single error there shifts the total the most.

Read the full guide →

Tool by the Super Simple Digital Tools Team. Reviewed by our editorial team. Free to use, no signup required.

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