How do I calculate APR on a loan myself (simple method)?

What Is APR?

APR stands for Annual Percentage Rate. It is the true cost of borrowing money, including interest AND all fees, expressed as a yearly percentage.

Why is this important? Because a loan might say "2% interest" but after adding a 5% processing fee, the real cost could be 50% or more. APR shows you the real cost.

The Simple Formula (Anyone Can Use)

APR = (Total Interest + All Fees) ÷ (Amount You Receive) ÷ (Loan Term in Days) × 365 × 100

Let me show you with real examples.

Example 1: A Simple Loan

You borrow ₦50,000. The lender charges ₦5,000 interest. You repay in 30 days. No other fees.

• Total cost: ₦5,000
• Amount received: ₦50,000
• Loan term: 30 days

Calculation:

1. ₦5,000 ÷ ₦50,000 = 0.10
2. 0.10 ÷ 30 = 0.00333
3. 0.00333 × 365 = 1.216
4. 1.216 × 100 = 121.6% APR

Example 2: A Loan with Hidden Fees (The Predator Special)

You borrow ₦50,000. The lender charges:

• ₦5,000 interest
• ₦3,000 "processing fee" (deducted upfront)
• You only receive ₦47,000
• You repay in 14 days

Calculation:

1. Total cost = ₦5,000 + ₦3,000 = ₦8,000
2. Amount received = ₦47,000
3. ₦8,000 ÷ ₦47,000 = 0.1702
4. 0.1702 ÷ 14 = 0.01216
5. 0.01216 × 365 = 4.438
6. 4.438 × 100 = 443.8% APR

This is why APR matters. The second loan looks similar but costs nearly four times as much.

The Official Method (For Reference)

The official APR calculation used by regulators is more complex. The Consumer Financial Protection Bureau (CFPB) provides detailed actuarial equations for precise calculation . The key principles are:

• All months are considered equal (30 days for monthly calculations)
• The term begins on the date the loan is given
• The term ends on the date the last payment is due
• The rate is determined by multiplying the periodic rate by the number of periods in a year 

Step-by-Step Action

Step 1: Before signing any loan, write down:

• How much money will ACTUALLY reach your hand (after all fees)
• How much money you must ACTUALLY pay back
• How many days until you must pay back

Step 2: Plug these numbers into the formula above.

Step 3: If the APR is above 100%, be very suspicious. If it is above 300%, it is predatory.

Step 4: Compare APRs across different lenders. Always choose the lowest APR, not the lowest monthly payment.

Step 5: If a lender refuses to give you the information needed to calculate APR, do not borrow from them.