Loan Calculator with Extra Payments

Get the monthly payment, the total interest and a yearly balance table for any fixed-rate loan, then test how much sooner an extra amount each month would clear it.

Runs in your browserFree, no sign-upLast reviewed October 8, 2026

Repayment summary

Monthly payment: 1,688.02
Total interest: 256,405.37
Total repaid: 506,405.37
Cost per borrowed unit: 2.03

Yearly breakdown

Period	Principal paid	Interest paid	Balance
Year 1	4,127.75	16,128.47	245,872.25
Year 2	4,404.19	15,852.02	241,468.06
Year 3	4,699.15	15,557.07	236,768.91
Year 4	5,013.86	15,242.36	231,755.05
Year 5	5,349.65	14,906.57	226,405.41
Year 6	5,707.92	14,548.29	220,697.49
Year 7	6,090.19	14,166.02	214,607.30
Year 8	6,498.06	13,758.15	208,109.23
Year 9	6,933.25	13,322.96	201,175.98
Year 10	7,397.58	12,858.63	193,778.40
Year 11	7,893.01	12,363.20	185,885.39
Year 12	8,421.62	11,834.59	177,463.76
Year 13	8,985.63	11,270.58	168,478.13
Year 14	9,587.42	10,668.80	158,890.71
Year 15	10,229.51	10,026.71	148,661.20
Year 16	10,914.59	9,341.62	137,746.61
Year 17	11,645.57	8,610.65	126,101.04
Year 18	12,425.49	7,830.72	113,675.55
Year 19	13,257.65	6,998.57	100,417.90
Year 20	14,145.54	6,110.68	86,272.37
Year 21	15,092.89	5,163.32	71,179.48
Year 22	16,103.69	4,152.53	55,075.79
Year 23	17,182.18	3,074.03	37,893.60
Year 24	18,332.91	1,923.31	19,560.70
Year 25	19,560.70	695.52	0.00

Quick answers

How much is the monthly payment on a 20,000 loan over 5 years?: At 7% a year, a 20,000 loan over 5 years costs 396.02 a month. You repay 23,761.44 in total, of which 3,761.44 is interest. Each 1 percentage point on the rate moves the payment by roughly 9 to 10 a month at this size and term.
How much interest do you pay on a 300,000 loan over 30 years?: At 6.5% the monthly payment is 1,896.20 and total interest is 382,633.47, so you repay 682,633.47 in all. At 6% the interest is 347,514.57 and at 7% it is 418,526.69.
How much does an extra 100 a month save on a loan?: It depends on the balance, rate and time left. On 300,000 at 6.5% over 30 years, an extra 100 a month clears the loan in 26 years and saves about 60,994.79 in interest. On 20,000 at 7% over 5 years it saves about 893.72 and finishes 13 months early.
Do extra payments reduce the principal or the interest?: Extra payments reduce the principal. Interest is charged each month on whatever balance remains, so a smaller balance means less interest in every later month and more of each normal payment going to principal. That compounding effect is why a small extra amount shortens a long loan by years.
What is the formula for a loan payment?: Payment = P × r ÷ (1 − (1 + r)^−n), where P is the amount borrowed, r is the annual rate divided by 12 and by 100, and n is the number of monthly payments. For a 0% loan the payment is simply P ÷ n.
Is it better to shorten the term or make extra payments?: Both cut interest in the same way, by repaying principal sooner. A shorter term commits you to the higher payment every month, and may come with a lower rate. Voluntary extra payments keep the lower required payment, which is safer if your income varies, provided your lender allows them without a penalty.

How Loan Calculator works

This loan calculator with extra payments takes four numbers: the amount borrowed, the annual interest rate, the term in years and an optional extra monthly payment. It returns the monthly payment, total interest, total repaid and a year-by-year table of principal paid, interest paid and remaining balance. With the default 250,000 at 6.5% over 25 years the payment is 1,688.02 and the interest comes to 256,405.37, slightly more than the sum borrowed. Add 200 a month and the loan clears in 19 years 6 months, saving roughly 64,927.88 in interest. It assumes a fixed rate, monthly payments and interest charged monthly on the reducing balance. Results are plain numbers with no currency symbol, so they read the same in dollars, pounds, euros or rupees.

What an extra monthly payment saves: three example loans

Each row is the note the tool shows under the Repayment summary for that Extra monthly payment. Rates and terms are examples, not offers.

Loan	Standard payment	Extra per month	Paid off in	Interest saved
20,000 at 7% over 5 years	396.02	50	4 years 5 months	508.42
20,000 at 7% over 5 years	396.02	100	3 years 11 months	893.72
25,000 at 7.5% over 5 years	500.95	100	4 years 1 month	1,013.61
250,000 at 6.5% over 25 years	1,688.02	100	21 years 11 months	37,671.20
250,000 at 6.5% over 25 years	1,688.02	200	19 years 6 months	64,927.88
250,000 at 6.5% over 25 years	1,688.02	500	14 years 11 months	115,668.35
300,000 at 6.5% over 30 years	1,896.20	100	26 years 0 months	60,994.79
300,000 at 6.5% over 30 years	1,896.20	200	23 years 1 month	103,448.79
300,000 at 6.5% over 30 years	1,896.20	500	17 years 6 months	179,759.08

The extra amount is assumed to be paid every month from the first payment until the loan is cleared. The last payment is cut to whatever balance is left, and the payoff time counts that final part payment as a full month.

Monthly payment per 1,000 borrowed, by rate and term

Multiply by the thousands you are borrowing for a quick estimate. For 18,000 over 5 years at 8%, 18 × 20.28 is about 365 a month.

Rate	3 years	5 years	10 years	15 years	20 years	25 years	30 years
3%	29.08	17.97	9.66	6.91	5.55	4.74	4.22
4%	29.52	18.42	10.12	7.40	6.06	5.28	4.77
5%	29.97	18.87	10.61	7.91	6.60	5.85	5.37
6%	30.42	19.33	11.10	8.44	7.16	6.44	6.00
7%	30.88	19.80	11.61	8.99	7.75	7.07	6.65
8%	31.34	20.28	12.13	9.56	8.36	7.72	7.34
10%	32.27	21.25	13.22	10.75	9.65	9.09	8.78
12%	33.21	22.24	14.35	12.00	11.01	10.53	10.29

Figures are the tool's Monthly payment for an Amount borrowed of 1,000. Scaling up by multiplication can differ from the exact result by a small rounding amount.

Worked examples: same loan, different term

A longer term lowers the payment and raises the total cost. These are the tool's results for 250,000 at 6.5%.

15-year term

Amount borrowed 250000, Annual interest rate 6.5, Term in years 15, Extra monthly payment 0

Monthly payment 2,177.77. Total interest 141,998.31. Total repaid 391,998.31. Cost per borrowed unit 1.57.

20-year term

Amount borrowed 250000, Annual interest rate 6.5, Term in years 20, Extra monthly payment 0

Monthly payment 1,863.93. Total interest 197,343.88. Total repaid 447,343.88. Cost per borrowed unit 1.79.

25-year term

Amount borrowed 250000, Annual interest rate 6.5, Term in years 25, Extra monthly payment 0

Monthly payment 1,688.02. Total interest 256,405.37. Total repaid 506,405.37. Cost per borrowed unit 2.03.

In the Yearly breakdown, year 1 pays 4,127.75 of principal and 16,128.47 of interest. Principal does not overtake interest until year 15.

30-year term

Amount borrowed 250000, Annual interest rate 6.5, Term in years 30, Extra monthly payment 0

Monthly payment 1,580.17. Total interest 318,861.22. Total repaid 568,861.22. Cost per borrowed unit 2.28.

Going from 15 to 30 years cuts the payment by 597.60 a month and adds 176,862.91 of interest.

Loan payment formula and how each payment is split

M = P × r ÷ (1 − (1 + r)^−n)

M is the monthly payment, P the amount borrowed, r the monthly rate (annual rate ÷ 12 ÷ 100) and n the number of payments (years × 12). Each month, interest = balance × r, the rest of the payment is principal, and the balance falls by that principal. For 10,000 at 8% over 3 years, r is 0.006667 and n is 36, giving 313.36 a month. The first month's interest is 10,000 × 0.006667 = 66.67, so 246.69 goes to principal. Over the three years the Yearly breakdown shows interest of 689.00, 434.08 and 158.00, which matches the Total interest of 1,281.09 apart from a 0.01 rounding difference.

How to read the results when you enter an extra payment

Monthly payment shows the standard payment plus your extra amount, so 1,688.02 becomes 1,888.02 when you add 200. That is what leaves your account each month.

Total interest, Total repaid, Cost per borrowed unit and the Yearly breakdown table all stay on the original schedule with no overpayment. They are the baseline. The note underneath the summary is where the overpayment result appears: the new payoff time and the interest saved compared with that baseline. To get the interest you would pay with the extra, subtract the saving from Total interest: 256,405.37 − 64,927.88 = 191,477.49 in the default example.

Cost per borrowed unit is Total repaid divided by Amount borrowed. A value of 2.03 means every 1,000 borrowed is repaid as about 2,030. It folds rate and term into one number, which makes two offers with different terms easy to compare.

What this calculator does not include

Fees. Arrangement, origination and valuation fees are not added, so compare the APR on real offers as well as the rate.
Variable rates. One rate is applied for the whole term. For a rate that will change, run the remaining balance again at the new rate.
Lump sums and yearly overpayments. Only a fixed extra amount every month is modelled.
Early repayment charges. Some lenders cap penalty-free overpayments, often as a percentage of the balance per year. Check your agreement first.
Taxes, insurance and other escrow items that some mortgage payments bundle in.
Fortnightly or weekly payment schedules. Payments are monthly.

Step by step

1
Type the loan balance into Amount borrowed, leaving out any deposit or down payment you are paying in cash.
2
Enter the Annual interest rate as a percentage, for example 6.5.
3
Set the Term in years. The box is set for 1 to 50, and a part year such as 2.5 is treated as 30 monthly payments.
4
Leave Extra monthly payment at 0 for the standard figures, or enter the amount you could add each month.
5
Read the Repayment summary, the note showing the new payoff time and interest saved, and the Yearly breakdown table.

Questions people ask

Does the yearly breakdown change when I add an extra monthly payment?

No. The Yearly breakdown always shows the standard schedule without overpayments. The effect of the extra amount is reported in the note above the table as a new payoff time and an interest saving.

Can I use this for a mortgage, car loan or personal loan?

Yes. Any fixed-rate loan repaid in equal monthly instalments uses the same arithmetic. Enter the amount you are financing, the rate and the term. It is not suited to interest-only loans, credit cards with changing balances or loans with a balloon payment at the end.

What is the difference between interest rate and APR?

The interest rate is the charge for borrowing the principal. APR also spreads compulsory fees across the term, so it is usually a little higher and is the better figure for comparing offers. Entering an APR here gives a payment slightly above the real one, because the fees are treated as interest.

Why is so little principal paid off in the early years?

Interest is charged on the outstanding balance, which is largest at the start. On 250,000 at 6.5% over 25 years, the first year pays 16,128.47 in interest and only 4,127.75 of principal. By year 25 the split has reversed to 695.52 of interest and 19,560.70 of principal.

How do I work out the remaining balance after a number of years?

Look at the Balance column in the Yearly breakdown. For 250,000 at 6.5% over 25 years the balance is 226,405.41 after year 5, 193,778.40 after year 10 and 148,661.20 after year 15, assuming no overpayments.

Does a 0% interest loan work?

Yes. With a rate of 0 the payment is the amount divided by the number of months. 10,000 over 5 years at 0% is 166.67 a month with no interest and a cost per borrowed unit of 1.00.

Should I overpay my loan or put the money into savings?

Overpaying earns a certain return equal to the loan's interest rate. Savings win only if the after-tax rate you can earn is higher. Most people keep an emergency fund and clear higher-rate debts first. This page gives the arithmetic, not personal financial advice.

How accurate are the results compared with my lender's figures?

For a fixed-rate loan with monthly payments they should match to within small rounding differences. Lenders may differ because of daily interest, a first payment date that is not exactly one month out, fees added to the balance, or rounding the payment up to a whole unit.