What formulas does this use?

The lump sum grows by FV = PV × (1 + i)^p, and regular contributions use the ordinary-annuity formula FV = PMT × ((1 + i)^p − 1) ÷ i, where i is the periodic rate and p is the number of periods. The two are added together.

How accurate is the projection?

It is a mathematical projection that assumes a constant rate and contributions made at the end of each compounding period. Real returns vary, inflation is not included, and it is an estimate — not financial advice.

Does the compounding frequency change the result?

Yes, slightly. More frequent compounding — monthly versus annually — earns a little more interest because returns are reinvested sooner. The difference grows with higher rates and longer periods. The contribution is treated as paid once per compounding period.

What is the difference between this and a compound interest calculator?

A basic compound interest calculator usually grows a single lump sum. This future value calculator adds a stream of regular contributions on top, using the annuity formula, which is closer to how real saving works.

Does it include inflation?

No. The result is a nominal projection. To see what it is worth in today's money, run the future value through an inflation calculator using your expected inflation rate.

Is my financial data private?

Yes. Every figure is calculated locally in your browser and nothing is ever sent to a server.

Future Value Calculator

Future value calculator

Project what your savings could grow to. Enter a starting amount, a regular contribution, an annual rate, the number of years and how often interest compounds — monthly, quarterly or annually. It is for anyone saving towards a long-term goal who wants to see the combined effect of an initial lump sum and ongoing deposits.

How it works

The calculator splits the projection into two standard time-value-of-money parts and adds them. With p = frequency × years periods and a periodic rate i = annual% ÷ frequency ÷ 100:

Lump sum: FV = PV × (1 + i)^p
Contributions (ordinary annuity): FV = PMT × ((1 + i)^p − 1) ÷ i

It then reports the total contributed (PV + PMT × p), the growth earned (future value minus what you put in) and the projected future value. Contributions are assumed to be made at the end of each compounding period.

Example

Start with 1,000, add 100 per month, at a 6% annual rate compounded monthly for 10 years:

periods p = 120, monthly rate i = 0.005
lump sum grows to ≈ 1,819
120 contributions of 100 grow to ≈ 16,388
future value ≈ 18,207, total contributed 13,000, growth earned ≈ 5,207

Note that the contribution is per compounding period: at the same 100 per period, monthly saving (1,200/year) builds far more than quarterly (400/year) or annual (100/year). The table below holds a 1,000 lump sum with no contributions so you can see the effect of frequency alone on a 6% rate over 10 years.

Frequency	Periods (10 yr)	Lump-sum future value
Monthly	120	≈ 1,819
Quarterly	40	≈ 1,814
Annually	10	≈ 1,791

It assumes a constant rate, so treat it as an estimate. Everything runs in your browser; your numbers never leave your device.