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Chemistry

Osmotic Pressure Calculator

Estimate ideal osmotic pressure from molarity, temperature and the van’t Hoff factor.

Explicit units and model assumptionsLocal calculations with worked examples
Chemistry workspace
Chemistry workspace

Check the units, concentration basis and assumptions before interpreting the result.

See the method

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Your chemistry result

Your result

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Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter molar concentration, temperature, van’t hoff factor.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

π = iMRT. With R = 8.31446261815324 L·kPa/(mol·K) and M in mol/L, pressure is in kPa.

A WORKED EXAMPLE

Using molar concentration = 0.1 mol/L, temperature = 298.15 K, van’t hoff factor = 1, the result is 247.895703 kPa. Change these example inputs to match your task; use the method above to check each step.

Understanding your result

The ideal particle concentration is i times molarity. This multiplication is the model’s way of accounting for dissociation into multiple solute particles.

What to keep in mind

Dilute ideal solution model; does not model membrane permeability or nonideal activity coefficients. Educational calculation only; use validated procedures for laboratory work.

Reference: OpenStax Chemistry 2e — chemical quantities and models

Common questions

How is molarity different from osmolarity here?

The ideal particle concentration is i times molarity. This multiplication is the model’s way of accounting for dissociation into multiple solute particles.

Are my inputs uploaded?

No. This calculation runs in your browser without an account or an external API.

Methodology maintained by ClarityKit. How these tools are built and checked.