GDP Deflator Calculator
From nominal GDP and real GDP, compute the GDP deflator: nominal GDP ÷ real GDP × 100, measuring overall price change vs the base period.
Input Data
Results
At a glance:The GDP deflator measures an economy's overall price level — the 'price-adjustment factor' between nominal and real GDP, as an index. Deflator = nominal GDP ÷ real GDP × 100. Nominal uses current prices, real uses base prices; the ratio is pure price difference × 100 (base = 100). =100 means same as base; >100 means prices above base (e.g. 110 = +10%); <100 means below. Its strength is full coverage: all domestically produced final goods and services (consumption, investment, government, exports), and its basket auto-updates with production mix (Paasche). It is one of the broadest inflation measures, best for 'whole-economy' price change.
Formula
GDP deflator = nominal GDP ÷ real GDP × 100.
$$\text{GDP Deflator} = \dfrac{\text{Nominal GDP}}{\text{Real GDP}} \times 100$$How to Use
- Enter nominal GDP at current prices.
- Enter real GDP at fixed base-period prices.
- View the deflator (>100 = prices above base).
Deflator from nominal and real GDP (HK$100M, base = 100)
| Scenario | Nominal GDP | Real GDP | Deflator | Price vs base |
|---|---|---|---|---|
| Inflation | 15,000 | 13,636.36 | 110.00 | +10% |
| Mild inflation | 15,000 | 14,285.71 | 105.00 | +5% |
| Base year | 14,300 | 14,300.00 | 100.00 | flat |
Deflator = nominal ÷ real × 100. 110 means ~+10% vs base; 100 means nominal = real.
Case Studies
Case 1: Derive the deflator from nominal and real GDP
Economy: nominal GDP 15,000 (current prices), real GDP 13,636.36 (base prices).
Deflator = 15,000 ÷ 13,636.36 × 100 = 110.
110 means overall prices ~10% above base. Because the deflator covers all domestic output, it reflects the broadest 'whole-economy' price level, more comprehensive than the consumption-only CPI.
Case 2: Implied inflation rate from the deflator
Last year deflator = 100 (base); this year nominal 15,000, real 14,285.71 → deflator = 15,000 ÷ 14,285.71 × 100 = 105.
Deflator inflation = (105 − 100) ÷ 100 × 100% = 5% — overall prices rose 5% in a year.
This 5% is usually close to but not equal to CPI inflation, because the deflator includes investment/exports and excludes imports. Watch both to cross-check inflation pressure and source.
FAQ
What is the GDP deflator; how does it measure prices?
The GDP deflator quantifies the price-adjustment factor between nominal and real GDP as an index: deflator = nominal ÷ real × 100. Nominal is at current prices, real at base prices; their ratio is the pure price difference, × 100 gives an index with base = 100. =100 means same as base; >100 means inflation since base (110 = +10%); <100 means below. Its hallmark is full coverage — it includes all final goods and services produced domestically (consumption, investment, government, exports), and its basket auto-shifts with actual production (Paasche), avoiding 'fixed-basket staleness'. So it is among the broadest price/inflation measures, ideal for overall-economy price change.
Why does the deflator differ from CPI?
Both measure prices but differ in scope and method, so inflation figures are close but not identical. Scope: the deflator covers all domestically produced final goods/services (incl. investment, government, exports) but excludes imports; CPI covers only a household consumption basket, excludes investment/government, but includes imported consumer goods. So investment/export price swings hit the deflator but not CPI; imported food/fuel price hikes hit CPI but not the deflator. Basket: traditional CPI uses a fixed base basket (Laspeyres), slow to update weights; the deflator's mix shifts with production (Paasche), reflecting structure in real time but harder to map to consumer feeling. For household living cost, CPI is closer; for overall-economy price level, the deflator is broader. Watch both to cross-check inflation.
How to convert nominal and real GDP with the deflator?
The deflator links nominal and real GDP; knowing any two gives the third. Base: deflator = nominal ÷ real × 100. From it: real GDP = nominal ÷ (deflator ÷ 100) — strips out price rise, giving base-price output (e.g. 15,000 ÷ 1.1 ≈ 13,636.36). And nominal GDP = real × (deflator ÷ 100) — restores current prices. This calculator does the third direction: from nominal and real, derive the deflator (= nominal ÷ real × 100). Useful in macro analysis: with official nominal and real GDP, derive inflation pressure, or convert a series between nominal and real. Note both real GDP and the deflator tie to the same base period — keep bases consistent when comparing.
Can the deflator be below 100?
Yes, with clear meaning: <100 means current overall prices are below the base — deflation since base. Recall base = 100. Example: nominal 9,500, real 10,000 (base prices) → deflator = 9,500 ÷ 10,000 × 100 = 95, i.e. ~5% below base. Causes: prolonged weak demand, or tech-driven price falls. Distinguish 'level' from 'inflation rate': even if >100 (still above base), a year-on-year decline means deflation that year. So judge deflation by the deflator's direction of change, not just its level.
Why is the deflator 'broader' than CPI?
Broader in coverage, but not always better — they complement. Coverage: the deflator includes all domestically produced final goods/services (household consumption, business investment, government purchases, exports); CPI only covers a household consumption basket, no investment/government. So when investment/export prices swing, the deflator captures it, CPI does not — broader for 'whole-economy' prices. And the deflator's mix auto-adjusts (Paasche), no stale-basket issue. But CPI has irreplaceable strengths: it focuses on household living cost, includes imported consumer goods, publishes frequently and timely, and is the standard for wages/pensions. So: deflator for overall-economy price level; CPI for household cost and sentiment — complementary, not substitutes. Pair with the CPI inflation calculator.
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References
Content review: Calculatorism Finance Team. Results are for reference only; please refer to the relevant authorities for the official figures.