The most powerful free weighted interest calculator. Compute the true blended interest rate across multiple loans, savings accounts, or credit lines by weighting each rate by its principal balance. See live interactive charts and step-by-step breakdowns.
Enter interest rates and balances to compute your true weighted blended rate across all accounts.
A weighted interest rate (also called a blended rate) is the average of multiple interest rates, where each rate is weighted by the outstanding balance or principal amount it applies to. Unlike a simple average, it reflects the true cost of borrowing or return on savings across all your accounts.
A simple average adds all rates and divides by count. A weighted average multiplies each rate by its balance, sums those products, then divides by the total balance. When loan amounts differ significantly, the blended rate gives a far more accurate picture of your true interest cost.
Type each account's annual interest rate (APR) into the 'Rate' column. These are the rates on your loans, mortgages, savings accounts, or credit lines.
Enter the outstanding balance or principal amount for each account. Larger balances have more influence on the blended rate.
The calculator computes your true weighted interest rate instantly. See the blended rate, total interest cost, and interactive breakdown charts update in real time.
The weighted interest formula: multiply each rate by its balance, sum those products, then divide by the total of all balances. Mathematically: r̄ = Σ(rᵢ × bᵢ) / Σ(bᵢ).
Enter each account with its interest rate and balance. For example: Mortgage 4.5% ($250,000), Car Loan 6.9% ($25,000), Student Loan 5.2% ($45,000).
4.5% × $250,000 = $11,250 · 6.9% × $25,000 = $1,725 · 5.2% × $45,000 = $2,340.
$11,250 + $1,725 + $2,340 = $15,315.
$250,000 + $25,000 + $45,000 = $320,000.
$15,315 ÷ $320,000 = 4.79%. Your true blended interest rate is 4.79%.
A 3% rate on $200K and an 18% rate on $5K have a simple average of 10.5%, but the weighted rate is only 3.37%. Ignoring balances dramatically overstates your cost.
APR is the annual rate without compounding. APY includes compounding effects. Make sure you use the same type of rate for all accounts when computing the blended rate.
If some accounts have variable rates, recalculate your blended rate periodically as rates change. A fixed-rate snapshot may become outdated.
Multiply each rate by its balance. Sum all products. Sum all balances. Divide. This calculator automates the entire process for accurate blended rates.
A borrower has a mortgage, car loan, and student loan at different rates. Compute the true blended interest cost.
The blended rate reflects the true cost of all debt. The mortgage dominates because it carries the largest balance.
An investor has funds across three savings accounts with different APYs. Find the overall weighted yield.
The high-yield savings account has the most influence because it holds the largest balance.
Determine your blended interest rate across all debts to evaluate whether a consolidation loan at a given rate would save money.
Compare your current weighted rate across multiple mortgages against a refinancing offer to make informed decisions.
Calculate your blended savings yield across accounts to identify if reallocating funds to higher-rate accounts is worthwhile.
Banks compute weighted average cost of funds across deposits to set competitive loan rates and maintain margins.
All balances must be positive. The calculator requires positive balances. A balance of zero means that account has no influence on the blended rate.
Equal balances = simple average rate. When every account has the same balance, the weighted interest rate equals the simple average of all rates.
Blended rate falls between lowest and highest rates. No matter the balance distribution, the blended rate will always fall between the lowest and highest individual rates.
Larger balances pull the blended rate toward that rate. The larger a balance relative to the total, the more the blended rate is pulled toward that account's rate. A $250K mortgage at 4% dominates over a $5K credit card at 18%.
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