Future value: what today's money becomes
The future value of money is what a sum today will grow to by a future date, once interest or returns have been added for every period in between. It is the mirror image of present value, and the single most useful idea in personal finance: it turns a vague hope that money will grow into an exact figure you can plan around. This calculator grows a lump sum at the compounding frequency you choose, and — because most real plans are not a single lump sum — it can add a fixed monthly deposit on top, so a starting pot plus steady saving is modelled the way an account actually behaves. The result is split honestly into the three parts you should always see: what you started with, what you added, and what growth itself contributed.
Future value is also the fair way to compare plans that start differently. A smaller amount started earlier can finish ahead of a larger amount started later, and the year-by-year table below the calculator shows the exact year the early start pulls ahead — the moment compounding stops looking gentle and starts looking powerful. For the lump-sum-only version with more compounding detail, the Compound Interest Calculator is the companion page.
The future value formulas
Monthly deposits: FV = PMT × ((1 + r ÷ 12)12 × t − 1) ÷ (r ÷ 12)
Where PV is the present value, r is the yearly rate as a decimal, n is the compounding frequency for the lump sum, t is the time in years, and PMT is the monthly deposit. The two parts are calculated separately and added: the lump sum compounds at your chosen frequency, while deposits grow at a monthly rate as an ordinary annuity, each deposit credited at the end of its month. If the rate is zero, the future value is simply everything you put in.
Why the interest slice keeps growing
In the first year, almost all of your balance is money you put in, and the interest is a thin slice on top. That balance of power reverses with time. Interest is charged on the whole balance — contributions plus all previous interest — so each year the growth is calculated on a larger base than the year before, even if you never add another cent. On long horizons the interest slice can pass your total contributions and keep going, which is why the table below tracks contributions and interest as separate columns: the year interest overtakes what you paid in is the year compounding truly takes over the plan. It is also why starting matters more than almost any other decision — a deposit made in year one compounds for the entire term, while the same deposit in the final year earns almost nothing.
Worked example
Start with $10,000 at 7% for 10 years, compounded annually, with no monthly deposits. The future value is $10,000 × (1.07)10 = $19,671.51 — the original ten thousand plus $9,671.51 of interest, very nearly a doubling in a decade. Now add a $200 monthly deposit and the picture changes shape: you contribute another $24,000 over the ten years, but those deposits also grow, each for however many months it is invested, and the combined future value rises well beyond the sum of the two parts calculated carelessly. Try it above — the deposits column in the table keeps the accounting honest, so growth never gets credit for money that was really yours.
Compounding frequency, in perspective
More frequent compounding grows the lump sum slightly faster, because interest is added — and starts earning its own interest — sooner. The effect is real but modest: at typical rates, daily compounding beats annual compounding by a small margin over a decade, far less than the effect of one extra year or a slightly higher rate. Frequency is therefore best treated as a tie-breaker between otherwise equal accounts. Note that on this page the frequency applies to the lump sum; monthly deposits are inherently monthly, so they are always modelled period by period at the monthly rate.
Worked example
With $10,000 today at 7% for 10 years, compounded annually and with no deposits, the future value is $19,671.51 — $10,000 contributed and $9,671.51 of interest. Add monthly deposits above and watch the interest column in the year-by-year table grow alongside them.
How to use this calculator
- Enter the present value — the lump sum you have today or will invest first.
- Enter the yearly interest rate or expected return, and how many years the money will grow.
- Choose how often the lump sum compounds, from annually to daily.
- Add a monthly deposit if you plan to keep contributing; leave it at zero for a pure lump-sum calculation.
- Read the future value, check how much of it is interest rather than your own money, and follow the year-by-year table to see when growth overtakes contributions.
Future value and inflation: the honest adjustment
A future value is stated in future dollars, and future dollars usually buy less than today's. If inflation averaged 3% a year over the same decade as the worked example, the $19,671.51 result would have the buying power of roughly $14,600 in today's terms — still real growth, because the 7% return outran inflation, but a smaller victory than the headline suggests. A quick discipline is to test your plan at a real rate: subtract expected inflation from your expected return and run the calculator again. Plans that still work at the real rate are plans built on saving, not on optimistic arithmetic.
What future value cannot promise
The formula assumes a smooth, fixed rate for the entire term. Bank interest on a fixed product can genuinely behave that way; investment returns cannot — they arrive unevenly, with down years mixed into up years, and the order matters when deposits are being added along the way. Use this page to understand the shape and scale of growth, to compare starting now against starting later, and to set contribution targets. For a goal funded purely by regular payments with no lump sum, the annuity view may fit better, and for retirement horizons the dedicated retirement tools add the spending side of the story as well.