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Financial calculators that run in your browser
Work out what a loan really costs you, and what happens when you pay a little extra each month. Your numbers never leave your device.
- Nothing to install
- No account needed
- Calculated on your own computer
Choose your calculator
The same tool in two languages. Pick the one you prefer.
Loan Payoff Calculator
See how much interest an extra monthly payment saves you, and how many months earlier you would finish paying.
- Compare up to 3 scenarios side by side
- Extra monthly payments and lump sums
- Full month-by-month schedule
Calculadora de Amortización
Calcula cuánto ahorras en intereses al hacer pagos extra y cuántos meses te adelantas en liquidar el préstamo.
- Compara hasta 3 escenarios a la vez
- Pagos extra mensuales y aportaciones puntuales
- Cuadro de amortización mes a mes
Más calculadoras en español: préstamo personal y TAE · ¿cuánta hipoteca puedo pagar? · bola de nieve o avalancha · ¿reducir cuota o plazo?
How it works
Enter your loan: the amount, the interest rate and the term. Nothing is sent anywhere.
Add an extra monthly payment, a one-off lump sum, or both — and see the effect immediately.
Compare scenarios side by side and read the full amortisation schedule, month by month.
Why a calculator that runs in your browser
Loan calculators usually ask for your details before showing you anything, and the numbers you type — how much you owe, what you earn, what you can afford — are exactly the kind of information worth keeping to yourself.
Lumera works differently. The calculations happen in your own browser, on your own computer. There is no account to create, no email to hand over, and no server that receives what you type. Close the tab and nothing is left behind.
It also means the tools work instantly, without waiting for a page to reload after every change. Adjust a figure and the result updates as you type.
Common questions
Is it really free?
Yes. The tools are free to use with no limits and no account. The site is supported by advertising.
Do you store the numbers I enter?
No. The calculations run in your browser and the figures are never sent to us. See the privacy policy for the detail.
Can I use it for a mortgage?
Yes, for any fixed-rate loan with regular instalments — mortgages, car loans or personal loans. Results are an estimate for guidance: your lender's own figures may differ slightly depending on how they apply early repayments.
Which language should I choose?
Both calculators do exactly the same maths. Pick whichever language you read more comfortably — you can switch at any time from the header.