Compound interest calculator: see how your savings grow
Drag the sliders and see how your savings grow when the return earns a return. Add a break from saving, or a few years of saving more, and see what it means for the final value. Free, in Swedish kronor, and nothing you enter is saved.
Results
- Starting capital
- 100 000 kr
- Your deposits
- 480 000 kr
- Return (compound interest)
- 822 041 kr
59 % of the final value is return.
- From 2034 your money earns more in a year than you save in a year.
- At 7 % a year, money takes about 10,2 years to double.
Growth year by year
Year by year
| Year | Per month | Deposited | Return | Value |
|---|---|---|---|---|
| 2027 | 2 000 kr | 24 000 kr | 7 761 kr | 131 761 kr |
| 2028 | 2 000 kr | 24 000 kr | 9 984 kr | 165 744 kr |
| 2029 | 2 000 kr | 24 000 kr | 12 363 kr | 202 107 kr |
| 2030 | 2 000 kr | 24 000 kr | 14 908 kr | 241 015 kr |
| 2031 | 2 000 kr | 24 000 kr | 17 632 kr | 282 647 kr |
| 2032 | 2 000 kr | 24 000 kr | 20 546 kr | 327 193 kr |
| 2033 | 2 000 kr | 24 000 kr | 23 664 kr | 374 857 kr |
| 2034 | 2 000 kr | 24 000 kr | 27 001 kr | 425 857 kr |
| 2035 | 2 000 kr | 24 000 kr | 30 571 kr | 480 428 kr |
| 2036 | 2 000 kr | 24 000 kr | 34 391 kr | 538 819 kr |
| 2037 | 2 000 kr | 24 000 kr | 38 478 kr | 601 296 kr |
| 2038 | 2 000 kr | 24 000 kr | 42 851 kr | 668 148 kr |
| 2039 | 2 000 kr | 24 000 kr | 47 531 kr | 739 679 kr |
| 2040 | 2 000 kr | 24 000 kr | 52 538 kr | 816 217 kr |
| 2041 | 2 000 kr | 24 000 kr | 57 896 kr | 898 113 kr |
| 2042 | 2 000 kr | 24 000 kr | 63 628 kr | 985 741 kr |
| 2043 | 2 000 kr | 24 000 kr | 69 762 kr | 1 079 504 kr |
| 2044 | 2 000 kr | 24 000 kr | 76 326 kr | 1 179 829 kr |
| 2045 | 2 000 kr | 24 000 kr | 83 349 kr | 1 287 178 kr |
| 2046 | 2 000 kr | 24 000 kr | 90 863 kr | 1 402 041 kr |
Use your household's real numbers
With a Sambokoll account the calculator starts from your actual savings and monthly saving, and the FIRE planner shows when you could stop working.
How the calculator works
- Each month the savings grow by the monthly return, (1 + yearly return)^(1/12) − 1, so a whole year grows by exactly the yearly return.
- Your monthly saving is added at the end of each month. A period with another amount replaces it for the years it covers; if periods overlap, the later one applies.
- Return = final value − starting capital − all deposits. That is the compound interest: return on the capital, on the deposits and on earlier return.
- Today's money = final value ÷ (1 + inflation)^years.
- With periods, the same plan is also calculated without them, and the difference is split into missed (or extra) deposits and return.
The calculation is an estimate, not financial advice. Returns are uncertain and past returns are no guarantee of future ones.
What makes the biggest difference
- Time — The return grows on itself every year it is left alone, so ten more years often matter more than a higher monthly amount.
- Starting early — Money saved early has the longest time to grow, so a break early on costs more than one late.
- Fees — A fee is taken every year, on everything: 1 % a year can eat a fifth or more of the final value over 30 years.
- Steady saving — A regular monthly saving, even a small one, keeps adding capital for the return to work on.
Want to know when your savings are enough to stop working? Try the FIRE calculator →
Compound interest in numbers
100,000 kr invested once at 7 % a year, with nothing more added. The return in the first year is 7,000 kr; by year 30 it is about 50,000 kr a year, because it is calculated on everything that has grown so far.
| Time | Value | Return |
|---|---|---|
| After 10 years | 196 715 kr | 96 715 kr |
| After 20 years | 386 968 kr | 286 968 kr |
| After 30 years | 761 226 kr | 661 226 kr |
Frequently asked questions about compound interest
What is compound interest?
Compound interest means that the return you earn starts earning a return too. If 100,000 kr grows by 7 % you have 107,000 kr after a year; the year after, the 7 % is calculated on 107,000 kr. Over many years the return on earlier return becomes the largest part of the savings.
How does the compound interest calculator work?
It goes month by month. The yearly return is converted to the equivalent monthly return, the savings grow by it, and your monthly saving is added at the end of each month. Periods with a different monthly saving replace the regular amount for the years they cover.
What return should I expect?
A broad global equity index fund has historically returned about 7 to 8 % a year before inflation, but returns vary a lot from year to year and future returns are uncertain. A savings account gives far less. Try a few levels, say 4, 6 and 8 %, to see the range.
What happens if I pause my saving for a few years?
You miss the deposits themselves and everything they would have grown to by the end of the saving period. A break early on therefore costs more than one close to the end. Add a period with 0 kr a month to see what a parental leave or a few years of study cost.
What is the rule of 72?
A rule of thumb for how long money takes to double: divide 72 by the yearly return in percent. At 7 % it takes about 72 ÷ 7 ≈ 10 years; at 4 % about 18 years.
Does the calculator include tax and fees?
No. Enter the return after fees to include them: a fund returning 7 % with a 0.2 % fee gives about 6.8 %. The yearly flat-rate tax on an investment savings account (ISK) or endowment insurance also lowers the return somewhat. Nothing you enter is saved.