EconixaECONOMICS FUNDAMENTALS

Interactive calculator

Gini Coefficient Calculator

Enter the share of total income going to each quintile (five groups of 20%). The calculator builds the Lorenz curve from your shares and computes the Gini coefficient: 0 means perfect equality, 1 means one household has everything. Try an equal split (Gini = 0) versus a skewed split to feel the scale. In this release this page is powered by the closest available interactive widget; a dedicated widget for this topic is planned.

Price Elasticity of Demand

Midpoint (arc) formula

Elasticity E = -1.500
Elastic (|E| > 1)
Steps
  1. Average quantity: (Q₁ + Q₂) ÷ 2 = (100.00 + 140.00) ÷ 2 = 120.00
  2. %ΔQ = (Q₂ − Q₁) ÷ avg Q = 40.00 ÷ 120.00 = 0.3333 (33.33%)
  3. Average price: (P₁ + P₂) ÷ 2 = (10.00 + 8.00) ÷ 2 = 9.00
  4. %ΔP = (P₂ − P₁) ÷ avg P = -2.00 ÷ 9.00 = -0.2222 (-22.22%)
  5. E = %ΔQ ÷ %ΔP = 0.3333 ÷ -0.2222 = -1.500
  6. Classification by |E| = 1.500: elastic — quantity responds more than proportionally to price.
Why the midpoint?

Using averages as the base removes the direction problem: going from P₁ to P₂ gives the same magnitude as going from P₂ to P₁. The negative sign just reflects the law of demand — classification uses the absolute value.

How to use it

  1. Enter income shares for each quintile (they must sum to 100).

  2. Read the Gini coefficient.

  3. Try equal and unequal distributions to calibrate your intuition.

What you will learn

  • Compute the Gini from quintile shares.
  • Interpret Gini values.
  • Explain what the Gini omits.