What this calculator does
Osmotic pressure (van’t Hoff) works out pressure needed to stop osmosis across a semipermeable membrane. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
Formulaπ = iMRT with R = 0.082057 L·atm/(mol·K)
The inputs explained
| Field | What to enter |
|---|---|
| Van’t Hoff factor | A number. Starts at 1. |
| Molar concentration (mol/L) | A number, measured in mol/L. Starts at 0.3. |
| Temperature (°C) | A number, measured in °C. Starts at 37. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with van’t hoff factor
Every other input is held at the calculator’s starting values while van’t hoff factor varies. Select any row to load that scenario into the calculator.