Real Interest Rate Calculator
Real Interest Rate Calculator
A nominal interest rate tells you how much money grows in raw dollar terms, but inflation erodes what that money can actually buy. The real interest rate strips out inflation to show your true gain in purchasing power — a 5% return during 3% inflation isn't really a 5% gain in what you can afford.
Investors and savers use the real rate to judge whether an investment is actually growing their wealth or merely keeping pace with rising prices — a nominal return below the inflation rate means a negative real return, even though the account balance is technically growing.
- Exact Fisher Equation: Real Rate = (1+Nominal)/(1+Inflation) − 1 — the mathematically precise version.
- Simple Approximation: Nominal − Inflation is commonly used as a quick estimate, and is close enough at low rates, but diverges more as rates rise.
- Negative Real Rates Happen: When inflation exceeds the nominal rate, your real return is negative — your money is losing purchasing power even while the account balance grows.
Why use the exact formula instead of just subtracting?
Simple subtraction (nominal − inflation) is a close approximation at low rates but becomes noticeably less accurate as either rate rises — the exact Fisher equation is always correct.
What does a negative real rate mean for my savings?
It means your money is technically growing but losing purchasing power faster than it earns interest — common during high-inflation periods with low savings account rates.
Real Interest Rate Calculator
A nominal interest rate tells you how much money grows in raw dollar terms, but inflation erodes what that money can actually buy. The real interest rate strips out inflation to show your true gain in purchasing power — a 5% return during 3% inflation isn't really a 5% gain in what you can afford.
Investors and savers use the real rate to judge whether an investment is actually growing their wealth or merely keeping pace with rising prices — a nominal return below the inflation rate means a negative real return, even though the account balance is technically growing.
- Exact Fisher Equation: Real Rate = (1+Nominal)/(1+Inflation) − 1 — the mathematically precise version.
- Simple Approximation: Nominal − Inflation is commonly used as a quick estimate, and is close enough at low rates, but diverges more as rates rise.
- Negative Real Rates Happen: When inflation exceeds the nominal rate, your real return is negative — your money is losing purchasing power even while the account balance grows.
Why use the exact formula instead of just subtracting?
Simple subtraction (nominal − inflation) is a close approximation at low rates but becomes noticeably less accurate as either rate rises — the exact Fisher equation is always correct.
What does a negative real rate mean for my savings?
It means your money is technically growing but losing purchasing power faster than it earns interest — common during high-inflation periods with low savings account rates.