Elasticity Simulator
Pick a good. Move the price. Watch quantity, revenue, and total consumer spending react. The steepness of the demand curve is the difference between "raise prices, make more money" and "raise prices, lose customers".
The one number pricing hinges on
Price elasticity of demand is the percent change in quantity divided by the percent change in price. If |E| > 1, demand is elastic — a price cut brings in more revenue than the loss per unit. If |E| < 1, demand is inelastic — you can raise prices and revenue goes up, because customers keep buying.
The rule that matters: to maximize revenue on an inelastic good, raise the price. On an elastic good, cut it. That's why concert tickets, luxury cars, and gourmet coffee raise prices freely — while airlines run constant sales. It's also why cigarette and gasoline taxes actually raise money: quantity barely drops.
What determines elasticity? Substitutes (many = elastic), necessity (yes = inelastic), share of budget (large = elastic), time (short-run = inelastic, long-run = more elastic — you can eventually switch fuels, cars, homes).