A single loan offer can show more than one percentage: an interest rate, an APR or comparison rate, and sometimes a “flat” rate. They are not three versions of the same number. Each is calculated a different way, and comparing one loan’s interest rate with another loan’s APR, or a flat rate with a normal interest rate, can make the more expensive loan look cheaper. This guide explains what each figure measures, works through one loan in all three forms, and ends with a checklist for comparing offers.
Run the numbers yourself
⚠️ About this page: the loan figures here are an illustrative example, not any lender’s product. Which fees an APR or comparison rate must include is set by each country’s rules, so check the disclosure rules where you live and the terms of the specific loan.
Interest Rate: What It Means
The interest rate is the price of borrowing the money itself. The US Consumer Financial Protection Bureau (CFPB) describes it as the cost you pay the lender for borrowing, on top of the loan amount — the principal. It is quoted as a yearly percentage, the nominal or quoted rate.
On most instalment loans the rate is applied to the balance you still owe. Each payment covers that month’s interest and repays part of the principal, so the balance shrinks and later payments carry less interest. This is called a reducing-balance or amortising loan, and it is what our EMI calculator models.
The interest rate leaves out two things that also decide what a loan costs: fees, such as an arrangement or processing fee, and the term. A lower rate with a large upfront fee, or a lower rate over a much longer term, can cost more in total than a higher rate on a shorter, fee-free loan. That is why the rate on its own is not a full comparison.
APR: What It Means
APR stands for annual percentage rate. It is designed to answer the question the interest rate leaves open: what does this loan cost per year once certain fees are counted too? The CFPB defines it as the interest rate plus additional fees charged by the lender, including origination charges and other fees charged when the loan is made, and notes that US federal law (the Truth in Lending Act) requires lenders to disclose it.
Because it adds fees to the interest, an APR is normally higher than the interest rate on the same loan, and equal to it when there are no fees to include. The two numbers measure different things, which leads to the most important rule in this guide, in the CFPB’s own words: compare APRs to APRs, not APRs to interest rates.
Two cautions. First, an APR does not always include every possible cost — which fees go in, and which stay out, depends on the country’s rules and the type of loan. Second, the APR does not set your payment: your monthly payment is calculated from the interest rate, while the APR is a comparison figure.
Source: CFPB — What is the difference between a loan interest rate and the APR?
Flat Rate: What It Means
A flat rate calculates interest on the original amount borrowed for the whole term, even though you repay part of it every month. In its simplest form it is simple interest on the starting principal:
Interest = 100,000 × 10% × 3 = 30,000
Total repayment = 100,000 + 30,000 = 130,000
Monthly payment = 130,000 ÷ 36 = 3,611.11
The catch is that by the last year of the loan you owe only a fraction of the principal, yet interest is still being charged as if you owed all of it. A reducing-balance loan charges interest only on what is outstanding. So a flat rate and a reducing-balance rate with the same number are not the same price: the flat-rate loan costs considerably more, as the worked example below shows.
Flat rates are not defined identically everywhere, and some lenders combine them with fees or different repayment schedules. If an offer quotes a flat rate, read the contract for how interest is actually calculated, and ask for the APR or the equivalent reducing-balance rate. Our simple interest calculator reproduces the flat-rate interest figure for any amount, rate and term.
APR vs Interest Rate vs Flat Rate
| Measure | What it represents | Fees included? | Common use | Main limitation |
|---|---|---|---|---|
| Interest rate | The yearly price of borrowing, applied to the outstanding balance on most instalment loans | No | Calculating the payment | Ignores fees, so it understates the cost of loans that carry them |
| APR / comparison rate | Interest plus certain fees, expressed as one yearly rate | Some or most, as defined by local rules | Comparing offers for similar loans | What it includes, and how it is calculated, differs by country and product |
| Flat rate | Interest charged on the original principal for the whole term | No | Some instalment-loan quotes | Looks lower than the equivalent reducing-balance rate |
Worked Example: One Loan, Four Ways
All four options below lend 100,000, repaid in 36 equal monthly payments. They are illustrative, not real products. “Equivalent reducing-balance rate” is the ordinary interest rate that would produce the same monthly payment, which puts the flat-rate options on the same footing as the others.
| Option | Monthly payment | Interest and fees over 3 years | Comparable yearly rate |
|---|---|---|---|
| A: 10% interest rate, no fees | 3,226.72 | 16,161.87 | 10.00% |
| B: 10% interest rate + 2,000 upfront fee | 3,226.72 | 18,161.87 | APR about 11.39% |
| C: 10% flat rate | 3,611.11 | 30,000.00 | about 17.92% equivalent |
| D: 6% flat rate | 3,277.78 | 18,000.00 | about 11.08% equivalent |
What the table shows:
- A and B share an interest rate but not a cost. In option B the fee is taken from the loan, so you receive 98,000 but repay as if you had borrowed 100,000. Spread over the term, that fee lifts the yearly cost from 10% to about 11.39%. That is what an APR is for.
- A 10% flat rate is not a 10% loan. Option C costs 30,000 in interest against 16,161.87 for option A — about 13,838 more for the same “10%”.
- The lowest headline number is not the cheapest loan. Option D’s 6% flat rate looks far lower than A’s 10%, but its monthly payment is higher and it costs more over the term. Only when D is converted to a comparable rate (about 11.08%) does the comparison become fair.
The APR in option B is calculated the common way for monthly-payment loans: the monthly rate that equates 98,000 received with the 36 payments, multiplied by 12. Some countries’ rules annualise with compounding instead, which gives a slightly higher figure for the same loan — about 12.01% here. Both methods agree that B is dearer than A; they differ only in how the yearly number is expressed, which is another reason to compare APRs only with APRs calculated under the same rules.
Why a Lower Interest Rate Does Not Always Mean a Cheaper Loan
- Fees. Upfront and ongoing fees add to the cost without changing the interest rate, as option B shows.
- Loan term. A longer term lowers the monthly payment but usually increases the total interest, because the balance stays outstanding for longer. Comparing two offers on the monthly payment alone favours the longer, more expensive one.
- Repayment frequency. Paying more often can reduce the balance sooner and slightly reduce interest on a reducing-balance loan; the effect depends on how the lender calculates interest.
- Calculation method. Flat versus reducing-balance makes the largest difference, but compounding frequency and day-count conventions also change the result. Our guide to the effective annual rate explains why two rates quoted with different compounding are not directly comparable.
- Fixed or variable. A variable rate can change during the term, so the cost you can calculate today is not guaranteed. An introductory rate that later rises is a version of the same problem.
APR and Comparison Rates Around the World
The idea of a single all-in comparison figure is widespread, but the name, what it includes and when it must be shown are set country by country. A few examples from the regulators themselves:
- United States — APR. The Truth in Lending Act requires lenders to disclose the APR, which the CFPB describes as the interest rate plus fees charged by the lender.
- Australia — comparison rate. ASIC explains that a comparison rate includes the interest rate and most fees and charges, but not all: government fees and charges, and charges that apply only in certain circumstances (such as paying the loan off early), are not included. Advertisements for fixed-term consumer credit that state an interest rate must also show a comparison rate, accompanied by a warning that it applies only to the example given.
- United Kingdom — representative APR. The FCA defines the representative APR in an advertisement as a rate at or below which the lender reasonably expects at least 51% of the resulting agreements to be made. Not every applicant will get it.
- India — APR in the Key Facts Statement. The Reserve Bank of India defines APR as the annual cost of credit to the borrower, including the interest rate and all other charges associated with the loan, and requires regulated lenders to give borrowers a Key Facts Statement for retail and MSME term loans sanctioned from 1 October 2024.
The practical point is the same everywhere: an all-in rate is the best single figure for comparing similar loans, but only when both figures were calculated under the same rules, and it still does not tell you everything in the contract.
How to Compare Loan Offers
- Compare like with like. Interest rate with interest rate, APR with APR. Never one offer’s interest rate against another’s APR.
- Check the APR or the applicable comparison rate, and that both offers state it for a similar loan amount and term.
- Check the upfront fees — arrangement, processing or origination fees, and whether they are paid in cash or deducted from the loan.
- Check the ongoing fees, such as monthly account or service fees.
- Check the loan term, and compare the total repaid, not only the monthly payment.
- Check the repayment frequency and how interest is calculated — reducing balance or flat.
- Check whether the rate is fixed or variable, and for how long any fixed or introductory rate lasts.
- Check what the advertised figure excludes, such as early-repayment charges, late fees, insurance or government charges.
Use Our Calculators
- EMI calculator — enter the interest rate (not the APR) to get the monthly payment and total interest on a reducing-balance loan. Run two offers side by side to compare their total cost.
- Car loan calculator — add any fees that are rolled into the loan, and see how much extra interest they cost over the term, as well as the total cost of the vehicle.
- Simple interest calculator — reproduces flat-rate interest on the original principal, and explains how to compare a flat-rate quote with a reducing-balance one.
Important Limitations
The examples and calculators on this site use standard formulas and the figures you enter. They do not reproduce any particular lender’s contract, its exact fee structure, tax treatment, payment dates or day-count conventions, or the APR method required in your country. Treat the results as estimates for comparing options, and rely on the lender’s own written disclosure for the actual figures.
Frequently Asked Questions
Is APR the same as the interest rate?
No. The interest rate is the cost of borrowing the money itself. The APR adds certain fees to the interest and expresses the total as one yearly rate. Your payment is calculated from the interest rate; the APR is for comparing loans.
Why is the APR usually higher than the interest rate?
Because it includes fees as well as interest. Spreading a fee such as a processing or origination fee over the term adds to the yearly cost. In the worked example on this page, a 2,000 fee on a 100,000 three-year loan at 10% gives an APR of about 11.39%.
What is a flat interest rate?
A rate that charges interest on the original amount borrowed for the whole term, even as you repay it. In its simplest form, interest equals principal times rate times years: 100,000 at a 10% flat rate for 3 years costs 30,000 in interest. Definitions vary between lenders, so check how the contract calculates interest.
Is a flat rate cheaper than a reducing-balance rate?
Not at the same headline number. Because a flat rate keeps charging interest on money you have already repaid, a 10% flat rate costs much more than a 10% reducing-balance rate. In the example on this page it costs about the same as a 17.92% reducing-balance loan.
Can two loans with the same interest rate have different APRs?
Yes. If one charges higher fees, its APR will be higher even though the interest rate is identical. That is exactly the difference the APR is designed to reveal.
Should I compare APR or interest rate?
Compare APRs (or comparison rates) with each other to see the cost including fees, and interest rates with each other to compare the payment. Never compare one loan’s APR with another loan’s interest rate. Then check the term, fees excluded from the APR, and whether the rate is fixed.
Does APR mean the same thing in every country?
No. The general idea is similar, but each country sets its own rules on what is included and how the rate is calculated. Australia uses a comparison rate, the UK uses a representative APR in advertising, and India requires the APR in a Key Facts Statement. Compare figures calculated under the same rules.
Sources
This page is written from the primary sources below — the providers’ own published terms and pricing, and the relevant regulators’ own published material. Links were last confirmed to load on . Providers change their terms without notice, so treat anything specific here as a starting point and confirm it against the source before acting on it.
How this page is researched
This page is desk research. It is built from published sources — regulators’ and deposit-protection schemes’ own material, and providers’ published terms where a concept needs one — not from personal testing. We explain the concepts in plain language, work through examples with the assumptions stated, and link to calculators so you can check the arithmetic with your own figures. Where a detail depends on a provider’s current terms, we say so. We have not necessarily opened or funded an account with any provider mentioned, so treat anything specific — a fee, a rate, an availability claim — as a starting point to confirm with the provider rather than a guarantee. Our about page sets out the method and its limits in full.
How we are funded. This site is supported by advertising. It does not use affiliate or referral links, and no provider pays to be mentioned or to influence what we write — see our disclosure.
Important: this page is general information for educational purposes only. It is not financial, investment, tax or legal advice, and it is not a recommendation to buy or use any particular product. Nothing here takes account of your personal circumstances or objectives.
Product features, fees, interest rates, availability and regulatory status change often and differ by country. Figures and details mentioned may be out of date — always confirm the current terms directly with the provider before acting. Investments can fall as well as rise in value, and you may get back less than you put in. Consider speaking to a qualified adviser who is authorised in your own country.