Investment Calculator

See how an investment grows with regular contributions, or find the contribution, rate, starting amount or time a goal needs.

Solve for

Currency

Starting amount

Contribution

Each month

How often you contribute

Paid in at

Return (% a year)

−50% to 50%

Returns compound

Years

1 to 100

Withdraw instead of contributingContributions rise each yearToday's money

End balance

$ 691,150

Total contributed

$ 180,000

Growth

$ 501,150

Your money$ 190,000

Growth$ 501,150

Contributions at the end of each month; returns compounded monthly.

At other returns

5% a year: $ 460,807
6% a year: $ 562,483
7% a year: $ 691,150
8% a year: $ 854,537
9% a year: $ 1,062,678

Balance ($)Your money ($)

0200K400K600K800K

Yr 10Yr 20Yr 30

Contributions ($)Growth ($)

020K40K60K

Yr 1Yr 6Yr 11Yr 16Yr 21Yr 26

Year-by-year breakdown

Year	Contributions ($)	Growth ($)	Balance ($)
Start	–	–	10,000
Year 1	6,000	919	16,919
Year 2	6,000	1,420	24,339
Year 3	6,000	1,955	32,294
Year 4	6,000	2,531	40,825
Year 5	6,000	3,148	49,973
Year 6	6,000	3,809	59,782

Projects how a starting amount and regular contributions grow at a yearly return, or finds whichever figure is missing: the contribution, starting amount, return or time that reaches a target. Contributions can be weekly to yearly, at the start or end of each period, rising each year, or taken out as withdrawals, and every balance can also be shown in today's money.

How to use it

Solve for — the figure worked out from the others and the Target. Switching keeps the last answer in the field that takes its place.
Return — -50% to 50%, negative for a falling market or a real-return view.
Paid in at — the end of each period (the usual convention) or the start, which gives each contribution one more period of growth.
Returns compound — daily to yearly, monthly by default.
Years — whole years, 1 to 100. Solving for years gives the time in years and months.
Withdraw instead of contributing — takes the amount out each period. Withdrawals stop when the balance runs out, and the result says in which year.
Contributions rise each year — by a percentage, such as a yearly pay rise. At the inflation rate it keeps contributions level in today's money.
Today's money — divides every balance by the inflation since the start, so a future sum reads in what it buys now.
At other returns — the end balance at the return 1 and 2 points either side.

How it works

The return compounds as chosen and is turned into the rate for one contribution period, so a yearly contribution with monthly compounding earns (1 + r ÷ 12)¹² − 1 a year, not r. Applying the yearly rate once per period instead, as some calculators do, gives a different answer whenever the two frequencies differ.

The contribution, starting amount and return are found by searching for the value whose end balance meets the target; the time is the first contribution at which the balance reaches it. A solved contribution is rounded up, and a withdrawal down, to the currency's smallest unit, and a starting amount up to the whole unit, so the target is still met. The real return comes from Fisher's relation on the effective yearly rate, not by subtracting inflation: 7% compounded yearly with 3% inflation is 3.8835% real, and 7% compounded monthly is 4.1058%.

FV = PV × (1 + i)ⁿ + PMT × ((1 + i)ⁿ − 1) ÷ i × (1 + i if paid at the start)

i = (1 + r ÷ c)^(c ÷ p) − 1

Real return = (1 + effective yearly return) ÷ (1 + inflation) − 1

n = contributions, p = contributions a year, c = compounding periods a year, r = annual return

Examples

500 a month for 30 years at 7%

With 10,000 to start, the balance reaches $ 691,150: you put in $ 190,000 and growth adds $ 501,150. Paying in at the start of each month instead gives $ 694,709.

The monthly amount that reaches 1,000,000

From 10,000 at 7% over 30 years, solving for the contribution gives $ 753.17 a month.

The return that doubles a sum in 10 years

10,000 with no contributions, compounded yearly, doubles in 10 years at 7.18% a year. The Rule of 72 estimates 72 ÷ 10 = 7.2%, close because the rule is built for rates near 8%.

Real against nominal

The first example with Today's money on at 3% inflation: the $ 691,150 buys what $ 284,745 buys today, because 7% compounded monthly is a real 4.11% a year and flat contributions lose value as prices rise.

Frequently asked questions

No figure is promised. Returns vary from year to year, and a long-run average says nothing certain about the next 30 years. Try a cautious rate and look at the strip of nearby returns, and use today's money to see what a future balance is worth.

Paying in at the start gives every contribution one more period of growth, so the balance ends higher by a period's growth on everything contributed. Most calculators and finance textbooks assume the end; choose the start if you invest as soon as you are paid.