Effective Interest Rate
Quick answer
Enter cash flows: net proceeds, payments, timing. Compare to nominal quote to see effective cost.
For a related estimate, see Apr Calculator.
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Why EIR differs
Nominal rate ignores timing of fees and compounding; effective rate aligns with cash out the door.
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Effective rate answers “what rate would a simple loan need to match this cash-flow pattern?” Useful when fees are withheld or compounding frequency differs. Use this when you are working from real inputs—quotes, listings, statements, or specs—not placeholder guesses alone.
How to use this calculator
- Fee timing: Upfront fees raise effective cost more than the same fees spread out.
- Compounding: More frequent compounding increases effective yield/cost at same nominal rate.
- IRR-style: True effective rate often needs IRR/XIRR thinking—use tool output as bracket.
Real-world examples
- Example: 5% origination fee withheld from proceeds can add materially to effective cost (illustrative).
- Sensitivity check: Nudge the rate by about +0.5% and the principal by about −5%. If the payment, break-even, or target amount moves enough to change your decision, you are still on a steep part of the curve where small inputs matter.
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What this means
Effective cost includes fee timing—two loans with identical note rates can differ materially after fees.
FAQ
Is this a loan commitment?
No. Outputs are educational estimates. Final payments, APR, and fees come from your lender’s disclosures.
How accurate is this calculator?
It applies standard math to the inputs you enter. Real lenders, payroll rules, and rounding can differ—use results for planning and comparison, not as binding quotes.
Why might my result differ from another website?
Different assumptions (APR vs note rate, day-count, tax year, rounding mode, or unit definitions) shift outputs slightly. Align inputs with the same definitions when you compare.