How Loan Payments Work: APR, Interest, and the True Cost of Borrowing
The advertised rate is not what you pay. APR is closer. Total cost of credit is the only number that tells the whole truth.
By Rohit Sharma, Founder, SEOShouts
Every instalment loan works the same way as a mortgage: a fixed payment covers the interest accrued since the last one, and whatever remains reduces the balance. The differences between loan offers come down to three numbers, and lenders advertise the least useful of them most prominently.
Interest rate versus APR
The interest rate is the cost of borrowing the money. The APR, annual percentage rate, folds in compulsory fees such as arrangement and administration charges, which is why it is usually the higher figure and always the more honest comparison.
| Loan A | Loan B | |
|---|---|---|
| Amount | £10,000 | £10,000 |
| Interest rate | 6.0% | 6.5% |
| Arrangement fee | £400 | £0 |
| APR | 7.6% | 6.5% |
| Total repaid over 5 years | £11,999 | £11,748 |
Loan A advertises the lower rate and costs more. The fee is what closes the gap, and only the APR reveals it. Where two offers run over the same term, comparing APR is enough.
Why term length matters more than rate
Stretching a loan over more years lowers the monthly payment, which is exactly why it is offered. It also means the balance is outstanding for longer, and interest is charged on the balance every month it exists.
| Term | Monthly payment | Total interest |
|---|---|---|
| 3 years | £304 | £946 |
| 5 years | £193 | £1,600 |
| 7 years | £146 | £2,271 |
Those are the figures for £10,000 at 6 per cent. Moving from three years to seven cuts the monthly payment by more than half and more than doubles the interest. The monthly figure is the one that feels affordable; the total is the one that is true.
Watch how early settlement is handled
Most modern loans use simple daily or monthly interest on the outstanding balance, so paying early genuinely reduces the interest you owe. Some older or subprime agreements use rule-of-78 interest allocation, which front-loads interest so that settling early saves much less than it should. Check which applies before assuming an overpayment helps.
- Ask for the total amount repayable, in writing, before signing.
- Check whether early settlement carries a fee, and how interest is rebated.
- Confirm that overpayments reduce the principal rather than being held against the next instalment.
- Treat payment protection insurance as a separate purchase and price it separately.
Secured against unsecured
Secured loans are backed by an asset, usually property or a vehicle, so the lender carries less risk and charges a lower rate. That lower rate is bought with the asset. Consolidating unsecured debt into a loan secured on your home lowers the payment and converts debt that could not have taken your house into debt that can.
Frequently asked questions
What is the difference between interest rate and APR?
The interest rate is the cost of borrowing alone. APR includes compulsory fees as well, so it reflects the real annual cost and is the fairer basis for comparing two offers over the same term.
Is a longer loan term ever a good idea?
It lowers the monthly payment and raises the total cost. It can be reasonable if the lower payment is what makes the borrowing affordable and safe, but it should be chosen knowingly rather than because the monthly figure looked better.
Does paying a loan off early always save money?
Usually, where interest is charged on the outstanding balance. Check for early settlement fees and for rule-of-78 interest allocation, which front-loads interest and reduces the benefit of settling early.
Calculators from this guide
About the author
Rohit Sharma is the founder of SEOShouts, a search consultancy in India, and has worked in technical SEO and content strategy since 2014. He builds and maintains Calcshark.