When to use this calculator
Estimate capillary rise or depression in a small circular tube. Negative results represent depression. The ideal model assumes a narrow circular tube and equilibrium.
Explore the fluids & flow calculators for other questions in this topic. For a related calculation, use the Continuity Equation Calculator: Find flow speed after a cross-sectional area change under continuity.
PUTTING IT INTO PRACTICE
Capillary Rise: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Surface tension (N/m) | 0.072 |
| Contact angle (degrees) | 0 |
| Liquid density (kg/m³) | 1,000 |
| Gravity (m/s²) | 10 |
| Tube radius (m) | 0.001 |
| Result | 0.0144 m |
- Check the input labels and enter the example values above.
- Apply the relationship: Rise = 2 × surface tension × cos(contact angle)/(density × gravity × tube radius).
- The result is 0.0144 m, rounded for display.
How to interpret your result
Negative results represent depression. The ideal model assumes a narrow circular tube and equilibrium.
Use the fluid properties at the relevant conditions. Gauge pressure is measured relative to a reference and differs from absolute pressure. Average flow velocity and characteristic length must match the geometry being modelled.
Frequently asked questions
Should hydrostatic pressure be added to atmospheric pressure?
Add the surface absolute pressure when an absolute result is needed. The basic liquid-column calculation alone gives the pressure increase with depth.
When is the capillary rise calculator useful?
Estimate capillary rise or depression in a small circular tube. Negative results represent depression. The ideal model assumes a narrow circular tube and equilibrium.
How do I use the capillary rise calculator?
Enter surface tension (n/m), contact angle (degrees), liquid density (kg/m³), gravity (m/s²), tube radius (m). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Rise = 2 × surface tension × cos(contact angle)/(density × gravity × tube radius).
What should I check before using the result?
Negative results represent depression. The ideal model assumes a narrow circular tube and equilibrium.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
Further reading
For background on this topic, see OpenStax: fluids, density and pressure ↗. This is a topic reference, not an external review or endorsement of this tool.
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