Nominal policy rate minus current inflation — negative real rates signal accommodative policy
Data as of May 15, 2026If your savings account pays 5% interest but groceries cost 7% more than last year, you have lost ground — your money buys less than it did before. The nominal rate is the number on the statement; the real rate is what is left after inflation has taken its bite. This distinction is the single most important concept in monetary policy. Central banks set nominal rates, but the economy responds to real rates.
The shortcut formula, known as the Fisher equation, is straightforward: real rate ≈ nominal rate − inflation. A worked example makes it concrete. Suppose the Federal Reserve has set the federal funds rate at 4.5% and US CPI inflation is running at 3.0%. The real rate is roughly +1.5% — your savings beat inflation by 1.5 percentage points per year, and a borrower at 4.5% is paying a real cost of 1.5% to use the money. Now imagine inflation jumps to 5.0% while the Fed leaves rates unchanged. The real rate flips to −0.5% — savers are losing purchasing power even as their balance grows on paper.
This is why central bankers obsess over the real rate. A positive real rate restrains the economy: borrowing genuinely costs something, savers are rewarded, and demand cools. A negative real rate accommodates the economy: it is cheaper to borrow than the inflation rate, which encourages spending and investment over saving. When the Fed says policy is "restrictive," it does not mean the nominal rate looks high in a historical chart — it means the rate sits above current inflation and above its best estimate of the neutral level. Conversely, holding nominal rates at 5% while inflation runs at 6% is, in real terms, still loose policy.
The Fisher decomposition i = r + πe separates the nominal rate into an ex-ante real rate and expected inflation. In practice, market-implied real rates are observed directly from the TIPS curve, with breakeven inflation — the spread between nominal Treasuries and TIPS of the same maturity — serving as a noisy proxy for inflation expectations net of liquidity and inflation-risk premia. The ACM term premium decomposition (Adrian-Crump-Moench) further isolates the expected short-rate path from the term-premium component, which materially affects how real yields should be interpreted as a policy-stance signal. Ex-post real rates (realized nominal minus subsequent CPI) and ex-ante real rates can diverge substantially when inflation surprises occur, as they did during 2021-2022.
The neutral real rate r* — the level consistent with output at potential and stable inflation — is itself a moving target. Holston-Laubach-Williams (2017) estimates show r* for the US declining from roughly 3.5% in the late 1990s to below 0.5% by 2019, with a tentative post-pandemic re-rating toward 0.7-1.2%. Hamilton, Harris, Hatzius and West (2016) argue most of the decline reflects slow-moving structural factors (demographics, productivity, global savings glut), making the post-2020 rebound contested. The real-rate gap — current ex-ante real rate minus estimated r* — is the cleanest stance indicator: a positive gap of, say, +1.5pp at 4.5% real with r* = 1.0% maps directly onto the inflation-gap term in a Taylor rule. Index choice is non-trivial: headline CPI overstates the policy-relevant signal because of energy passthrough; core PCE is the Fed's preferred measure; trimmed-mean PCE (Dallas Fed) and services-ex-housing inflation increasingly drive Committee deliberation post-2023. Substituting headline CPI for core PCE can shift the implied real rate by 50-150 basis points during volatile periods.
The real interest rate adjusts the nominal policy rate for inflation. A positive real rate means policy is restrictive in real terms; a negative real rate means it is accommodative even if nominal rates appear elevated.
Accommodative — inflation exceeds the policy rate
Broadly neutral monetary stance
Restrictive — policy rate exceeds inflation
Formula: Real Rate = Nominal Policy Rate − Current CPI Inflation
| Central Bank | Currency | Policy Rate | Inflation (CPI) | Real Rate |
|---|---|---|---|---|
| Federal Reserve | USD | 3.62% | 0.0% | +3.62% |
| European Central Bank | EUR | 2.00% | 2.0% | +0.02% |
| Bank of England | GBP | 3.75% | 3.4% | +0.35% |
| Reserve Bank of Australia | AUD | 3.96% | 3.7% | +0.26% |
| Bank of Japan | JPY | 0.30% | 0.0% | +0.30% |
| Bank of Canada | CAD | 5.25% | 2.4% | +2.87% |
| Reserve Bank of India | INR | 5.25% | 5.0% | +0.30% |
| Swiss National Bank | CHF | N/A | N/A | N/A |
| People's Bank of China | CNY | N/A | N/A | N/A |
See the full methodology or explore individual central bank pages for detailed rate analysis including Taylor Rule implied rates.