The calculators on this site answer questions about your own money. These are different. They are working models of how a market, a firm, or a whole economy behaves, built so you can pull the levers yourself and watch what breaks.
Teaching with these? There is a page mapping all fourteen to a standard intro micro and macro syllabus, with notes on using them on a projector, as homework, or as the counterexample.
Will the money last? Most calculators draw one smooth line. This one runs a thousand lives and shows why the order your returns arrive in can matter more than the average.
Test a plan → S02Value a company the way an analyst does. Forecast free cash flow, build the discount rate from its parts, and read the sensitivity grid that shows how little certainty a single number deserves.
Value a company → S03Five years, twenty quarters, four decisions each. Set price, headcount, marketing and R&D against a rival who fights back, and find out whether contribution margin covers your fixed costs before the bank stops lending.
Take the job → S04You run the economy. Set interest rates, spending, and taxes, then watch inflation, GDP, and unemployment respond through a Phillips curve, Okun's law, and adaptive expectations. Shocks arrive whether you are ready or not.
Run the economy → S05Two lines crossing, and everything that breaks them. Drag a rent ceiling, a minimum wage, or a sales tax and watch shortages, tax incidence, and deadweight loss appear on the diagram.
Open the market → S12Price any bond and watch the price-yield curve bend. Duration, convexity and DV01, checked against a full repricing, plus a yield curve you can invert to read the forward rates hiding inside it.
Price a bond → S13The only free lunch in finance. Drag correlation and watch two risky assets combine into something safer than either alone, with the efficient frontier drawn as you go.
Build a portfolio → S14A country worse at making everything still gains from trade. Set each economy's productivity, pick the terms of trade, and watch both sides consume beyond what they could produce alone.
Open the model → S08Why markets overproduce pollution and underproduce beehives, and how a tax sized to the damage raises total welfare instead of destroying it.
Open the model → S09Who actually pays for protection? Split the loss to consumers into producer gain, government revenue and the part that reaches nobody, then compare an equivalent quota.
Set a tariff → S10Read a Lorenz curve, see where the Gini coefficient comes from, test how far redistribution moves it, and meet two economies that score identically while looking nothing alike.
Read the curve → S11Type any 2x2 payoff matrix and it solves: best replies, dominant strategies, every Nash equilibrium including the mixed ones, and which outcomes waste value. Six classic games are built in.
Solve a game → S06When is losing money the right call? Marginal, average and variable cost curves, the shutdown point, and the moment a firm's supply curve appears out of its own costs.
Find the shutdown point → S07Why a firm with no competitors deliberately sells less than it could, how marginal revenue falls below price, and what market power costs everyone else.
Open the model →None of these went up until its output had been reproduced a second way: a closed-form formula, a numerical derivative, or an identity that has to hold exactly. The methods page walks through four of those checks with real figures, and lists the errors they caught.
Students trying to build intuition for concepts that are hard to grasp from a textbook diagram, and anyone curious about why economic policy involves so much arguing. No background is assumed, and each model explains its own mechanics on the page.
They are accurate as teaching models, not as forecasts. Each one implements textbook relationships faithfully, and each states its assumptions and limits openly. A real forecasting model would add open-economy effects, financial frictions, heterogeneous households, and forward-looking expectations. Simplifying is deliberate, since it makes the mechanism visible.
A calculator answers a question you already know how to ask. A simulator teaches you why the question is hard. Most economics is about tradeoffs, and tradeoffs are far easier to understand when you have personally tried and failed to avoid one.