Sinking fund at 20 percent
By Jude Wallis
At 20 percent, the sinking fund factor for 5 periods is 0.13438. Multiply a cash amount by that factor. This column is independently recomputed.
The formula
Multiply a target future amount by the factor to get the deposit each period.
| n | 20% |
|---|---|
| 1 | 1.000000 |
| 2 | 0.454545 |
| 3 | 0.274725 |
| 4 | 0.186289 |
| 5 | 0.134380 |
| 6 | 0.100706 |
| 7 | 0.077424 |
| 8 | 0.060609 |
| 9 | 0.048079 |
| 10 | 0.038523 |
| 11 | 0.031104 |
| 12 | 0.025265 |
| 13 | 0.020620 |
| 14 | 0.016893 |
| 15 | 0.013882 |
| 16 | 0.011436 |
| 17 | 0.009440 |
| 18 | 0.007805 |
| 19 | 0.006462 |
| 20 | 0.005357 |
| 21 | 0.004444 |
| 22 | 0.003690 |
| 23 | 0.003065 |
| 24 | 0.002548 |
| 25 | 0.002119 |
| 26 | 0.001762 |
| 27 | 0.001467 |
| 28 | 0.001221 |
| 29 | 0.001016 |
| 30 | 0.000846 |
| 35 | 0.000339 |
| 40 | 0.000136 |
| 45 | 0.000055 |
| 50 | 0.000022 |
Worked example
Using the 20 percent column, what factor sits at 5 periods, and what is 10,000 times that factor?
- Read down the 20 percent column to row 5, giving 0.13438.
- Multiply: 10000 x 0.13438.
The factor is 0.13438. The product is 1343.8.
How these figures were checked
Every factor on this page is recomputed before the site can build, by a separate program that works a different way: repeated multiplication instead of a power function, a period-by-period sum instead of a closed-form annuity factor, and a solved loan schedule instead of a payment formula. If the two methods disagree anywhere, the page does not ship. Printed factor tables carry typos because nobody can check three thousand numbers by hand; this one is checked on every build.
Keep reading
This page is educational material, not financial advice. The figures come from the formula shown and assume the inputs you enter hold for the whole term. Your own rate, fees, taxes and timing will differ, so treat the output as arithmetic to check a decision against, not as a recommendation.