Economics Calculators

Price elasticity of demand by the midpoint (arc) or point method, with the elastic/inelastic classification and the total-revenue test worked out step by step.

Consumer surplus, producer surplus, and total gains from trade — from a market price and quantity, or by solving linear demand and supply curves for equilibrium.

Solve the deflator identity for nominal GDP, real GDP, or the deflator itself — and turn two deflators into the economy-wide inflation rate between them.

The Keynesian spending multiplier from MPC — spending, tax, and balanced-budget multipliers plus the round-by-round geometric series showing where the total GDP change comes from.

The money multiplier and the maximum money a deposit can support under fractional-reserve banking, with a round-by-round lending table and a fuller model adding currency drain and excess reserves.

Deadweight loss from a per-unit tax or observed price gap — the Harberger triangle, tax revenue, trades lost, and an optional elasticity-based split of who bears the burden.

Market concentration by the Herfindahl–Hirschman index — squared shares, the DOJ/FTC 2023 merger-guideline bands, the numbers equivalent, and the ΔHHI of a hypothetical merger.

The equation of exchange MV = PY solved for any variable, plus the growth-rate form that turns money growth into implied inflation — with the velocity caveats stated honestly.

Income inequality from a pasted list of incomes — the Gini coefficient by the sorted closed form, the Lorenz curve behind it, and the income shares of the top 10% and bottom 50%.

GDP growth as a simple, BEA-style annualized-quarterly, or average annual rate — the three headline conventions from the same two observations, with per-capita growth and rule-of-70 doubling time.

Marginal cost from a single cost change or a full cost schedule — per-unit MC, average total cost, marginal revenue, and the profit-maximizing output under the MR = MC rule.

The benchmark policy interest rate the Taylor rule prescribes from inflation and the output gap — with a term-by-term decomposition and a comparison against the actual rate.

Cross-price elasticity — are two goods substitutes or complements — and income elasticity with the normal, inferior, and luxury classification, by the midpoint or point method.

Translates an unemployment gap into an output gap (or GDP growth into a predicted unemployment change) using Okun's rule of thumb — with an adjustable coefficient, because it is an empirical regularity, not a constant.