Prepayment simulator
Try lump sums and extra payments that grow each year, and watch the payoff date move.
- Lump sums
- Growing extra
- Shorter term
Free · private · no sign-up
Loan calculator: know every payment before you sign.
Monthly payment, total interest, payoff date and a full amortization schedule in seconds. Everything runs in your browser — nothing you type is uploaded.
- No account needed
- Runs in your browser
- CSV download
Fix the highlighted fields to see your results.
Monthly payment
- Principal
- Interest
- Total interest
- Total paid
- Payoff date
- Number of payments
Extra payment savings
Amortization schedule
| Period | Payment | Principal | Interest | Balance |
|---|
Payments include any extra payment. Amounts are rounded for display.
Your numbers stay on this device. Results are estimates, not financial advice.
App features
Everything here, plus the tools you’ll want next.
The web calculator covers the basics. The Android app keeps your loans, reminds you when a payment is due and answers the harder questions.
- Currencies
- 26
- Languages
- 12
- Works offline
- 100%
- Accounts needed
- 0
Refinance comparison
Put your current loan next to a new rate and term to see whether switching pays off.
- Current vs new
Affordability
Start from a monthly budget and work back to the loan amount it can carry.
- Budget → loan
Compare saved loans
Save offers from different lenders and compare them side by side.
- Side by side
Real APR with fees
Add fees to see the true yearly cost, not just the headline rate.
- Fees included
Export, reminders, widgets
PDF and CSV export with your branding, payment reminders and home-screen widgets.
- CSV
- Widget
26 currencies, 12 languages, fully offline
No account and no sign-in. Your saved loans stay on your phone.
- USD
- EUR
- GBP
- INR
- VND
- IDR
- PHP
- THB
- JPY
- KRW
- CNY
- TWD
- MXN
- BRL
- +12
Screenshots
See it on Android.
FAQ
Frequently asked questions
How is the monthly payment calculated?
For equal monthly payments we use the standard annuity formula: payment = P × r ÷ (1 − (1 + r)−n), where P is the loan amount, r is the yearly rate divided by 12 and n is the number of months. Each payment first covers that month’s interest on the remaining balance; the rest pays down the principal. At 0% the payment is simply P ÷ n.
Equal payments or equal principal — which is better?
With equal payments (an annuity) every instalment is the same, which is easy to budget. With equal principal you repay the same slice of principal each month plus interest on what is left, so the first payment is the largest and payments fall over time. Equal principal costs less interest overall but needs more cash at the start. Switch the method in the calculator to compare.
How do extra payments work?
The extra amount goes straight to principal every month. Your required payment doesn’t change, but the balance falls faster, so the loan ends sooner and you pay less interest. Ask your lender whether prepayment fees apply.
Is my data sent anywhere?
No. Every calculation runs in your browser. The numbers you type are saved only in this browser’s local storage so they’re still here next time; they are never uploaded. We count page views and button clicks with Google Analytics, which never receives loan amounts or rates. See the privacy policy.
Is there an iPhone app?
Not yet. Loan Calculator is available for Android on Google Play. This web calculator works on any phone, tablet or computer.
Are the results exact?
They are estimates. Lenders may round differently, count days differently or add fees and insurance. Use the results to compare options and confirm the final figures with your lender. Nothing here is financial advice.
Your loan plan, in your pocket.
Save loans, get payment reminders and compare offers side by side. The Android app works fully offline.
- No account
- Works offline
- 26 currencies