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ECONOMICS • MACROECONOMICS

IS,LM Equilibrium & Monetary Policy

Reveal the IS and LM schedules step by step, then change money supply, prices and interest sensitivities to see how output and the interest rate move.

● JOINT MARKET EQUILIBRIUMIS ↔ LM
Equilibrium output
Interest rate
Real money supply
Investment

Reasoning inspector

live model state
Output Y—
Interest rate r—
Real money supply—
Investment—
Goods demand—

Experiment with the mechanism

The IS,LM model links planned spending in the goods market with money demand and money supply. Their intersection gives the output and interest-rate combination consistent with both markets at once.

LEARN WITH THE SIMULATION

Understand IS,LM Equilibrium & Monetary Policy by experimenting.

START HERE

The IS,LM framework combines a goods-market equilibrium schedule with a money-market equilibrium schedule. The IS curve collects output and interest-rate combinations consistent with planned spending, while the LM curve collects combinations consistent with real money supply and money demand. Their intersection is the model's joint short-run equilibrium.

BUILD THE IDEA

What you should understand first

  • Distinguish the goods-market IS schedule from the money-market LM schedule.
  • Explain how a larger real money supply shifts money-market equilibrium and changes the joint equilibrium.
  • Connect interest sensitivity in spending and money demand to the slopes and policy response of the two schedules.

TRY IT YOURSELF

What happens to output and the interest rate when nominal money supply rises while the price level stays fixed?

  1. Record the baseline equilibrium output and interest rate.
  2. Increase nominal money supply with all other controls unchanged.
  3. Replay the IS and LM reveal.
  4. Compare the new intersection with the baseline and explain the LM-side mechanism.
Read the visual:

A larger nominal money supply raises real balances when the price level is fixed. In this simplified setup the LM schedule moves toward lower interest rates for a given level of output, so the joint equilibrium generally has a lower interest rate and higher output.

WHY IT WORKS 01

Why monetary expansion moves the LM side

Money demand rises with output and falls with the interest rate in this model. When real money balances increase, the same output can be supported at a lower interest rate because more liquidity is available relative to transactions demand. Geometrically, the LM schedule shifts, and the new intersection with IS determines the model's output and rate response.

WHY IT WORKS 02

Slope matters for policy transmission

The size of the equilibrium response depends on how interest-sensitive spending is and how strongly money demand responds to output and interest rates. A very interest-sensitive goods market can turn a modest rate movement into a larger spending response, while a money-demand schedule that absorbs extra balances easily can change the rate effect. Policy transmission therefore depends on behavioral parameters, not only on the size of the money-supply change.

DO NOT MIX THESE UP

Common misconception

IS,LM is not a complete modern monetary-policy model. It treats the price level as fixed within the exercise, compresses financial markets into a money-demand relation, and omits expectations, credit spreads, forward guidance, open-economy channels and many institutional details.

PRACTICE CHALLENGE

Can you create a case where a large money-supply increase produces only a small output response?

  • Record the baseline equilibrium.
  • Increase nominal money supply substantially.
  • Adjust the spending or money-demand sensitivities to make equilibrium output move less.
  • Replay the schedules and explain which slope absorbs more of the policy change.
Reveal the reasoning

Yes. The intersection response depends on both curve slopes. If spending is weakly responsive to interest rates, a monetary expansion can lower the equilibrium rate without producing a proportionally large increase in output. Different behavioral sensitivities therefore change how the same money-supply shock is transmitted.

MODEL BOUNDARIES

What this simulation assumes

Every simulation simplifies reality or a mathematical system. These are the assumptions and limits to keep in mind while interpreting the results.

Model assumptions

  • The goods market is summarized by linear interest-sensitive spending schedules.
  • Money demand is linear in output and the interest rate, while nominal money supply and the price level are exogenous.
  • The model solves a static short-run equilibrium with one representative interest rate.

Model limitations

  • The price level, expectations, banking frictions, risk premia and modern central-bank operating procedures are simplified or omitted.
  • IS,LM is used as an educational comparative-statics framework rather than a calibrated forecasting model.

CONNECT IT

Where this matters

  • Introductory macroeconomics
  • Monetary-policy transmission intuition
  • Goods and money market interaction
  • Comparative statics

WORDS THAT MATTER

Key vocabulary

IS curve
Combinations of output and interest rate consistent with goods-market equilibrium in the model.
LM curve
Combinations of output and interest rate consistent with real money supply equaling money demand.
Real money balances
Nominal money supply divided by the price level.
Joint equilibrium
The output and interest rate where both IS and LM conditions hold simultaneously.