Personal and car loans
Enter loan amount, annual rate, and term to see repayments and total interest. Term can be entered in years or months — useful for car finance. Add an optional extra monthly payment to model faster payoff.
How this loan calculator works
Amortising instalment loans
Enter principal, annual interest rate, and term (years or months) to estimate regular repayments and total interest for a standard amortising loan — the structure used by many personal loans and car-finance contracts. An optional extra monthly payment models paying down faster.
This is educational maths, not a lender quote. Fees, insurance, variable rates, and early-repayment charges are omitted unless you fold them into the inputs yourself.
Core idea
Each payment covers some interest and some principal. Early payments are interest-heavy; later payments clear more principal. Extra monthly amounts cut the balance sooner, reducing total interest and often shortening the schedule.
Worked example
A £10,000 loan at 8% APR over 3 years has a higher monthly payment than the same loan over 5 years, but lower total interest. Adding £50 extra per month noticeably reduces both term and cumulative interest compared with minimums alone.
Common mistakes
- Confusing nominal APR advertising with the compounding convention your contract uses.
- Entering term in years while thinking in months (or the reverse).
- Ignoring balloon payments or dealer finance quirks.
FAQs
- Is this a mortgage tool?
- Mortgages share amortisation maths but often need different assumptions — see Mortgage.
- Snowball vs avalanche?
- For multiple debts, use Debt Payoff.
When this page helps
Use it when you want a transparent, browser-side calculation with the assumptions spelled out — then verify anything high-stakes against primary docs, a professional, or your own measurements. The related links below point to sibling tools and longer guides when you need more context.
Accuracy notes
Results depend entirely on the numbers you enter and the simplified model described above. Device clocks, tape measurements, market rates, and recipe conventions can all differ from a perfect textbook case. If an output looks surprising, re-check units first, then re-read the formula section.
Related: Mortgage, Interest, Debt Payoff.
Last updated: July 2026