Blended Rate vs APR — What's the Difference?
Blended rate and APR are both 'single rate' numbers, but they measure very different things. Learn when to use each and how they're calculated.
Blended Rate Calculator
Your true weighted average rate across multiple existing loans
What it measures: The weighted average interest rate across two or more loans you already hold, based solely on stated interest rates and outstanding balances.
✓ Use when
- You have a first mortgage and HELOC and want a single combined rate
- You're evaluating whether to consolidate multiple debts
- A lender offers a refinance — you need your current blended rate to compare
- You want to understand your aggregate borrowing cost today
✗ Limitations
- Does not include fees, points, or closing costs
- Uses simple interest math only — does not account for monthly compounding
- Only applies to loans you already hold
APR Calculator
The true all-in annual cost of a single new loan offer
What it measures: The Annual Percentage Rate on a single loan, factoring in origination fees and discount points alongside the stated interest rate.
✓ Use when
- Comparing two mortgage offers with different rates and fee structures
- A lender quotes you a rate plus points — you want the all-in cost
- Evaluating whether paying discount points makes sense
- Required by TILA to be disclosed on all consumer loan offers
✗ Limitations
- Only applies to a single loan — cannot combine multiple debts
- Assumes you hold the loan to maturity (refinancing early changes the effective APR)
- Does not show your aggregate borrowing cost across an existing portfolio
Key difference
Blended rate is a backward-looking tool — it describes the aggregate cost of loans you already have. APR is a forward-looking regulatory metric — it describes the all-in cost of a new loan offer you are evaluating.
Worked Example
Scenario
You have a $300,000 mortgage at 6.5% and a $50,000 HELOC at 8.5%. A lender offers to refinance both into a $350,000 loan at 6.8% with $3,500 in origination fees.
Your current blended rate = 6.79% (weighted average of the two existing loans)
The refinance offer APR = 6.94% (includes the $3,500 fee spread over 30 years)
Interpretation
The stated rate of 6.8% looks lower than your 6.79% blended rate, but once fees are included, the APR is 6.94% — higher than your current blended cost. The refinance does not save you money.
Bottom line
Use your blended rate to understand what you currently pay. Use APR to evaluate any new loan offer. Compare the two numbers to decide whether refinancing or consolidating actually helps.