Example 1
- Principal: 200,000
- 6%, 20 years
- +500/mo.
≈ 93 mo. sooner
Interest − ≈ 61,565
A steady extra shortens a 20-year loan a lot.
Loan overpayment calculator
Type remaining principal, the annual interest rate, and the remaining term in years. The calculator compares a no-extra case with one overpayment scenario. At 200,000, 6%, 20 years, and an extra 500 a month you drop about 93 payments and about 61,565 of interest.
Extras go to principal. One baseline versus one scenario. Full table: amortization schedule. A sketch, not a contract rule.
Result
Enter your numbers and hit Calculate - the result shows up right away.
How results are calculated
The loan overpayment calculator sets a level annuity payment with no extras next to the same loan with extras. At remaining principal 200,000, 6%, 20 years, and Extra monthly overpayment 500, the term shrinks by about 93 payments and interest falls by about 61,565. At 150,000, 7.5%, 15 years, and a One-time lump sum of 20,000 you drop about 38 payments and about 34,082 of interest. Both sides of the compare use the same fixed rate.
People open this calculator when they already have a contract and want to see what 500 above the payment is worth. You type Remaining principal, not the amount from origination day, if you have already paid some down. Regular monthly payment can stay blank: the calculator then builds an annuity from principal, rate, and term. A payment typed from your schedule wins over the formula. Overpayment handling is Reduce term or Reduce payment after a lump.
Required fields are Remaining principal, Annual interest rate (%), and Remaining term (years). Options include One-time lump sum, Lump on payment number, Next payment / start date, and Prepayment fee / penalty. At 80,000, extra 200, a 5,000 lump, and a 200 fee, net interest saved is about 15,396 with about 36 fewer payments. The fee comes off the savings, not off principal in month one.
The amortization schedule builds the full table with a monthly, yearly, or one-time extra on a chosen payment. Debt repayment times a horizon from a balance and a fixed payment, without a contract compare. This calculator stays with one scenario versus the base. It does not guess whether the contract allows extras without a fee.
Header currency only labels the amounts. A comma and a period in 7.5 mean the same rate. The calculator waits for positive principal, rate, and term. This is a fixed-rate sketch, not a credit decision and not an amendment from an offer.
Type 200,000, 6, 20, and 500, click Calculate, and check about 93 fewer payments. Then try 150,000, 7.5, 15, and a 20,000 lump to see about 38 payments and 34,082.
How to use
- Type Remaining principal, for example 200,000, Annual interest rate (%), for example 6, and Remaining term (years), for example 20.
- Add Extra monthly overpayment, for example 500, or a One-time lump sum and the payment number in Lump on payment number.
- Regular monthly payment can stay blank so the annuity is used. In Overpayment handling pick Reduce term or Reduce payment.
- Click Calculate. At 200,000, 6%, 20 years, and +500/month you drop about 93 payments and about 61,565 of interest.
- For the full table, open the amortization schedule. A horizon from balance and a fixed payment lives on debt repayment.
Overpayment into principal and fewer payments
One baseline versus one extras case. At 200,000, 6%, 20 years, and +500 a month you drop about 93 payments and about 61,565 of interest.
- overpayment
- Cash above the scheduled payment, applied to principal. +500/mo on 200,000 / 6% / 20 years saves about 61,565 and about 93 payments.
- annuity
- The default payment when Regular monthly payment is blank. 200,000 at 6% for 20 years is the base behind those 93 fewer payments.
- Prepayment
- The fee field. On 80,000 with +200/mo and 5000 once, a 200 fee leaves about 15,396 interest saved net of the fee.
Usage examples
Example 2
- Principal: 150,000
- 7.5%, 15 years
- Lump: 20,000
≈ 38 mo. sooner
Interest − ≈ 34,082
A one-time payment cuts principal immediately.
Example 3
- Principal: 80,000 · +200/mo. + 5,000
- Fee 200 · start date
≈ 36 mo. sooner
Interest − ≈ 15,396 (net of fee)
Both extras in one scenario; payoff date shown.
Example 4
- 150,000
- 5.5%
- 15 years
- +250/mo
≈ 42 mo. sooner
Interest − ≈ 18,226
How many months sooner with an extra 250 a month on 150,000 at 5.5% over 15 years? ≈ 42 mo. sooner, Interest − ≈ 18,226.
Example 5
- 80,000
- 7%
- 10 years
- +150/mo
≈ 22 mo. sooner
Interest − ≈ 6,365
How many months sooner with an extra 150 a month on 80,000 at 7% over 10 years? ≈ 22 mo. sooner, Interest − ≈ 6,365.
Which tool to use for overpaying and repaying debt
- Loan overpayment - fastest way to see how much interest and how many months you save by paying extra into an existing loan.
- Repayment schedule - full month-by-month table with instalments, balance and any extra payments; useful when you need the entire path, not just a summary.
- Debt repayment - for a single debt balance and a fixed monthly payment, when you want to know how many months it will take to reach zero.
If you only need a quick answer to “is overpaying worth it?”, start here. When you need a full schedule or a payoff horizon at a fixed payment, go to the repayment schedule or debt-repayment calculator instead.
Related calculators
FAQ
How much does +500 a month cut on 200,000 at 6% for 20 years?
About 93 payments. Interest falls by about 61,565. The extra goes to principal above the annuity payment.
What does a 20,000 lump do on 150,000 at 7.5% for 15 years?
About 38 fewer payments and about 34,082 less interest when Overpayment handling is Reduce term.
What is the net at 80,000, +200, a 5,000 lump, and a 200 fee?
About 36 fewer payments and about 15,396 interest net of the fee. The 200 comes off savings, not off the first principal slice.
Can Regular monthly payment stay blank?
Yes. A blank field takes the annuity from principal, rate, and term. A typed contract payment wins over the formula.
How is Reduce term different from Reduce payment?
Reduce term keeps the payment size and finishes earlier. Reduce payment after a lump rebuilds the payment over the same remaining term. A teaching shortcut.
Does 500 come off the contractual payment?
No. The 500 sits above the payment. The payment stays; the balance falls faster. A contract may recast the payment only after an amendment.
Where is the month-by-month table?
On the amortization schedule. Here you get one baseline-versus-scenario compare, not a 240-row chart.
Does a comma in 7.5 work?
Yes. 7,5 and 7.5 are the same rate. Header currency only labels the result.
Is the prepayment fee required?
No. Prepayment fee / penalty is optional. Blank means zero in this sketch, not permission from the contract.
Is 61,565 a guarantee from an offer?
No. It is a fixed-rate sketch from the numbers you type. An offer may compute differently and may add a fee.
Knowledge sources
Extras go to principal at the fixed rate you type. This is a sketch, not a contract rule.
Page updated in 2026.