Loan amortisation calculator
The level payment for any loan, and where every pound of it goes: the interest and capital split each year, and the balance still outstanding. Quoted the CM1 way, with an effective annual rate.
| Paid | Interest | Capital | Still owed at year end | |
|---|---|---|---|---|
| Year 1 | 13,875.32 | 9,684.83 | 4,190.49 | 195,809.51 |
| Year 2 | 13,875.32 | 9,475.30 | 4,400.02 | 191,409.49 |
| Year 3 | 13,875.32 | 9,255.30 | 4,620.02 | 186,789.48 |
| Year 4 | 13,875.32 | 9,024.30 | 4,851.02 | 181,938.46 |
| Year 5 | 13,875.32 | 8,781.75 | 5,093.57 | 176,844.89 |
| Year 6 | 13,875.32 | 8,527.07 | 5,348.25 | 171,496.64 |
| Year 7 | 13,875.32 | 8,259.66 | 5,615.66 | 165,880.98 |
| Year 8 | 13,875.32 | 7,978.87 | 5,896.44 | 159,984.54 |
| Year 9 | 13,875.32 | 7,684.05 | 6,191.26 | 153,793.28 |
| Year 10 | 13,875.32 | 7,374.49 | 6,500.83 | 147,292.45 |
| Year 11 | 13,875.32 | 7,049.45 | 6,825.87 | 140,466.58 |
| Year 12 | 13,875.32 | 6,708.15 | 7,167.16 | 133,299.42 |
| Year 13 | 13,875.32 | 6,349.80 | 7,525.52 | 125,773.90 |
| Year 14 | 13,875.32 | 5,973.52 | 7,901.80 | 117,872.10 |
| Year 15 | 13,875.32 | 5,578.43 | 8,296.89 | 109,575.21 |
| Year 16 | 13,875.32 | 5,163.59 | 8,711.73 | 100,863.48 |
| Year 17 | 13,875.32 | 4,728.00 | 9,147.32 | 91,716.17 |
| Year 18 | 13,875.32 | 4,270.63 | 9,604.68 | 82,111.48 |
| Year 19 | 13,875.32 | 3,790.40 | 10,084.92 | 72,026.56 |
| Year 20 | 13,875.32 | 3,286.15 | 10,589.16 | 61,437.40 |
| Year 21 | 13,875.32 | 2,756.70 | 11,118.62 | 50,318.78 |
| Year 22 | 13,875.32 | 2,200.76 | 11,674.55 | 38,644.23 |
| Year 23 | 13,875.32 | 1,617.04 | 12,258.28 | 26,385.95 |
| Year 24 | 13,875.32 | 1,004.12 | 12,871.19 | 13,514.75 |
| Year 25 | 13,875.32 | 360.56 | 13,514.75 | 0.00 |
Interest each period is the outstanding balance times the periodic rate; the rest of the payment repays capital, so the split shifts from interest-heavy to capital-heavy over the term. “Still owed” is the loan outstanding after that year’s payments: the present value of the remaining payments (the prospective method), or the loan rolled up less payments rolled up (retrospective) — both give the figures above.
Two ways to the same balance
CM1 asks for the outstanding loan two ways. Prospectively it is the present value of the remaining payments; retrospectively it is the original loan rolled up with interest, less the payments rolled up. They always agree, and the schedule above is both at once. The interest share starts large because interest is charged on the whole balance; each payment shrinks the balance, so later payments are mostly capital. This is also why overpaying early in a mortgage saves so much interest.
Make it stick. Studying CM1? The loan schedule question is a fixture. Memori's shop carries a ready-made CM1 set, and the notation cheat sheet covers the symbols. Memori is a flashcard app built by actuarial students — join the beta.
For education only, not financial advice.