Surface tension converter
Type a surface tension, choose the units, and see the result in every common unit. Lab data often uses dyn/cm while SI papers use mN/m; the two numbers are identical.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Type a number. A dot or a comma works as the decimal separator.
- Choose the unit you have and the unit you need. The ⇄ button swaps them.
- The table shows the same value in all common units at once.
Conversion factors
Every unit is converted through N/m.
| Unit |
In N/m |
| 1 mN/m |
0.001 |
| 1 dyn/cm |
0.001 |
| 1 lbf/ft |
14.59390294 |
| 1 lbf/in |
175.12683528 |
The pound-force is 0.45359237 kg × 9.80665 m/s² = 4.4482216 N.
Worked example
A liquid has a surface tension of 22 mN/m. That is 22 dyn/cm and 0.022 N/m. A value of 0.05 N/m is 50 mN/m, or 50 dyn/cm.
Tips
- Surface tension falls as temperature rises, so quote the temperature with the value.
- Contact angle and wetting are separate properties and cannot be derived from surface tension alone.
Frequently asked questions
Is 1 dyn/cm equal to 1 mN/m?
Yes, exactly. 1 dyn = 10⁻⁵ N and 1 cm = 10⁻² m, so 1 dyn/cm = 10⁻³ N/m = 1 mN/m. The numbers are always the same.
How do I convert 72 dyn/cm to N/m?
Divide by 1,000: 72 dyn/cm is 0.072 N/m. Water against air is in this range at room temperature, falling a little as it warms.
Is surface tension the same as energy per area?
They have the same dimensions, and 1 N/m equals 1 J/m². Surface tension is the force per unit length along a surface, or equivalently the energy needed to enlarge it by one square metre.
How many N/m is one pound-force per foot?
1 lbf/ft = 4.4482216 N ÷ 0.3048 m = 14.5939 N/m. One lbf/in is 12 times larger, 175.1268 N/m.