How to calculate the total cost of a loan before you sign
How to calculate what a loan costs in total, how rate, term and fees change it, and how to compare offers using the APR and the Truth in Lending disclosure.
Quick answer
The total cost of a loan is everything you pay above the amount borrowed: monthly payment × number of payments − loan amount + fees. Example: $10,000 at 12% APR costs $1,957 in interest over 36 months and $3,347 over 60 months. Compare offers by APR and total of payments, not just the monthly payment.
Key takeaways
- Total cost = payment × payments − amount + separate fees.
- $10,000 at 12%: $1,957 interest over 36 months, $3,347 over 60.
- Compare by APR and total of payments, not just the payment.
- Origination fees may be deducted from what you receive.
When you compare loans, the monthly payment is the first thing you see, but not the most important. Two loans with similar payments can differ by hundreds or thousands of dollars. The number that really matters is the total cost: everything you pay above the money you receive.
The basic formula
Total cost of credit = (monthly payment × number of payments) − amount borrowed + fees not included in the payment
The payment on a fixed-rate loan comes from the amortization formula. You do not have to do it by hand: the personal loan calculator gives you the payment, the interest and the full schedule.
Example: same loan, different terms
A $10,000 loan at 12% APR:
| Term | Monthly payment | Total interest |
|---|---|---|
| 36 months | $332.14 | $1,957 |
| 60 months | $222.44 | $3,347 |
The 60-month term lowers the payment by about $110 but adds almost $1,400 in interest. Neither option is “right” for everyone: it depends on whether the higher payment fits comfortably in your budget.
Example: the rate changes everything
If on $10,000 over 36 months you get a 6% APR instead of 12%, the payment drops from $332.14 to $304.22 and interest falls from $1,957 to $952. Six percentage points are worth about $1,000 here.
Fees that raise the cost
- Origination fee: a percentage of the loan that is sometimes deducted from the money you receive. Borrow $10,000 with a $500 fee and you receive $9,500 but pay interest on $10,000.
- Late fees.
- Prepayment penalty: less common on personal loans, but check.
- Optional add-ons such as credit insurance. They are not required unless the contract clearly says so; you can decline them.
Why APR is the number to compare
A loan’s APR includes the interest rate plus certain required fees, expressed as a yearly percentage. That is why it is usually a bit higher than the interest rate. The Truth in Lending Act (TILA) requires the lender to give you a disclosure before you sign with:
- The APR.
- The finance charge: the cost of credit in dollars.
- The amount financed.
- The total of payments.
Compare those figures across offers with the same term. More in what is APR.
Checklist before you sign
- What are the APR and the total of payments?
- How much money will I actually receive after fees?
- Is the rate fixed or variable? (See fixed vs. variable interest rates.)
- Is there a prepayment penalty?
- What happens if I miss a payment?
- Does the payment fit my budget even if my expenses rise a bit?
High-cost loans
Some products, such as payday loans or auto title loans, can carry very high APRs and very short terms. Before using them, compare alternatives such as credit unions, payment plans with the creditor or community assistance. Rules vary widely by state.
The bottom line
The monthly payment answers “can I pay this every month?” The total cost answers “what does this money cost me?” You need both answers before you sign.
Frequently asked questions
How do I calculate the total cost of a loan?
Multiply the monthly payment by the number of payments, subtract the amount borrowed and add any fees not included. The loan calculator does it for you.
Is a shorter or longer loan term better?
A longer term lowers the payment but raises total interest. Choose the shortest term whose payment fits comfortably in your budget.
What is an origination fee?
A charge, usually a percentage of the loan, sometimes deducted from the money you receive even though you pay interest on the full amount.
Which document shows the true cost of a loan?
The Truth in Lending (TILA) disclosure, with the APR, finance charge, amount financed and total of payments.
Sources
- Regulation Z (Truth in Lending), 12 CFR Part 1026 eCFR
- Consumer tools Consumer Financial Protection Bureau
This article is general and educational; it is not personalized financial, legal or tax advice. Financial product terms change: always confirm current terms with the institution.