Complex Interest Calculator

Formatting only. This does not change the calculation.
The lump sum already invested or deposited today. Use 0 if you are starting from nothing.
Banks advertise an APY, lenders a nominal rate. Say which one you typed in the field below.
Choosing APY converts the quoted yield back to the nominal rate its compounding schedule implies, so a full year returns exactly the APY you typed.
Amount added every contribution period. Leave at 0 for a pure lump sum.
Raises the contribution once a year, for example to track a pay rise.
Used only to restate the final balance in today's purchasing power.
Applied to the interest earned to show an after-tax balance. Use 0 for a tax-sheltered account.
Every figure is always computed; this only decides which one is presented as the answer.
Future value
16,288.95
Compound Interest Calculator
Total you put in
10,000.00
Of which contributions
0.00
Compound interest earned
6,288.95
Effective annual yield (APY)
5.0000 %
Equivalent nominal annual rate
5.000000 %
Multiple of what you put in
1.6289
Balance after tax on interest
16,288.95
Future value in today's money
16,288.95
Years for the balance to double
14.21
Average interest a year
628.89
Average interest a month
52.41
Worked out from Compound interest formula A = P(1 + r/n)^(nt), and the future value of an annuity FV = PMT[((1+i)^N - 1)/i] and 3 other sources.

How this is worked out

5 steps
  1. Rate per compounding period = 5% / 1 compounding annually (1 a year).
  2. Effective annual yield = (1 + r/n)^n - 1 = 5%.
  3. No recurring contributions, so the balance grows from the 10000 starting amount alone.
  4. Future value after 10 years = 16288.95, of which 6288.95 is compound interest on 10000 paid in.
  5. At this yield the balance doubles every ln(2)/ln(1+i) = 14.21 years.
Year-by-year balancetable
yearcontributionsinterestbalance
1050010,500
2052511,025
30551.2511,576.25
40578.8112,155.06
50607.7512,762.82
60638.1413,400.96
70670.0514,071
80703.5514,774.55
90738.7315,513.28
100775.6616,288.95

Results are general information, not financial, tax, legal, medical or engineering advice.