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Price Index Calculator

Enter each item's base- and current-period prices and quantities to instantly compute the Laspeyres, Paasche, and Fisher price indices. See how the overall price level has shifted against a base of 100, with a per-item breakdown.

Input

Enter one item per line as "name, base price, current price, base quantity, current quantity", separated by commas. The item name is optional.

Result

Laspeyres index (base period = 100)

119.0

With the base period set to 100, prices rose about 19.0% (weighted by base-period quantities).

Paasche index

118.8

Fisher index

118.9

Items

3 items

Breakdown by item

ItemBase priceCurrent priceBase qtyCurrent qty
Rice400480108
Milk20023067
Eggs25030045

Totals used in the calculation

Σ base price × base qty (p₀q₀)6,200
Σ current price × base qty (pₜq₀)7,380
Σ base price × current qty (p₀qₜ)5,850
Σ current price × current qty (pₜqₜ)6,950

How it works

  • The Laspeyres index uses base-period quantities as weights and is computed as (Σ current price × base qty) ÷ (Σ base price × base qty) × 100. It is the classic price-index method, used for measures such as the Consumer Price Index.
  • The Paasche index uses current-period quantities as weights and is computed as (Σ current price × current qty) ÷ (Σ base price × current qty) × 100. Its distinguishing feature is that it reflects the current consumption mix.
  • The Fisher index is the geometric mean of the Laspeyres and Paasche indices, namely √(Laspeyres × Paasche). It is an intermediate measure that offsets the biases of the other two.
  • All indices are expressed with the base period set to 100. A value above 100 means prices have risen, while a value below 100 means they have fallen.
  • Enter one item per line as "name, base price, current price, base quantity, current quantity", separated by commas. The item name can be omitted, in which case items are numbered automatically.
  • This calculation deals with price indices and is a separate concept from variance, which measures the spread of data. Variance distinguishes the sample variance (divided by n) from the unbiased variance (divided by n−1), but this tool's index calculation does not use either.