Surface Tension Converter

Convert surface tension values among common SI, metric and customary units. Surface tension is force per unit length along a liquid interface. Numerically, one mN/m equals one dyn/cm.

ValueEnter zero or a positive value; scientific notation is accepted.Convert fromNewton per meter (N/m)Millinewton per meter (mN/m)Dyne per centimeter (dyn/cm)Pound-force per inch (lbf/in)Pound-force per foot (lbf/ft)Convert toNewton per meter (N/m)Millinewton per meter (mN/m)Dyne per centimeter (dyn/cm)Pound-force per inch (lbf/in)Pound-force per foot (lbf/ft)

Convert

Converted value72 dyn/cm

SI-base value0.072 N/m

Multiply by1

The displayed results apply to the default example. Enable JavaScript to convert other values.

How to use this converter

1. Enter the surface tension value.
2. Select its current unit and the unit you want.
3. Select Convert. The page shows the converted value, the SI-base value and the direct multiplication factor.

Conversion formula

Converted value = entered value × source-to-SI factor ÷ target-to-SI factor.

Every option is represented by its factor to newton per meter (N/m). This one-base method keeps reciprocal conversions consistent. Calculations run in your browser, and old results are hidden when an input changes or validation fails.

Worked example

Convert 72 mN/m to dyn/cm. Multiply by 1; the result is 72 dyn/cm. The same input equals 0.072 N/m in the SI-base unit.

Accuracy and limitations

Surface tension varies with temperature, contaminants and composition. A converted literature value may not represent a real sample.

The calculator retains more digits internally than it displays. Round the final value to the precision supported by your measurement. Very large and very small answers may use scientific notation.

Frequently asked questions

Why do mN/m and dyn/cm have the same number?

Both units equal 0.001 N/m, so their numerical values are identical.

Can I reverse the conversion?

Yes. Swap the From and To selections. Because both units use the same SI base, the reverse factor is the reciprocal of the forward factor.

Why was my entry rejected?

Use digits with an optional decimal point or scientific notation. Blank values, commas, fractions, words and non-finite entries are rejected. Negative values are rejected because this converter treats the quantity as a magnitude.

Review notes and sources

Reviewed October 4, 2026. The conversion factors, default example, zero or signed boundary behavior, invalid-input handling and recovery after an error were checked. Factors follow SI definitions and published conversion guidance from the NIST Guide to the SI and the BIPM SI Brochure. Explanations and examples are original.

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