Surface Tension Converter

Surface tension is the force along a liquid's surface per length, written γ (gamma): γ = F / L. It comes from the molecules at the surface pulling on each other, which makes the surface act like a stretched film. It is why water forms drops, rises in a thin tube, and holds up a water strider.

Its SI unit is the newton per meter (N/m), but values are usually given in millinewtons per meter (mN/m) or dynes per centimeter (dyn/cm), which are the same size. Water at 20 °C has a surface tension of about 72.8 mN/m.

Surface tension is also the energy needed to make new surface per area, so ergs per square centimeter measure the same thing: 1 erg/cm² = 1 dyn/cm.

How to convert surface tension

Type a value into any field, and every other unit is calculated at once. For example, water at 72.8 mN/m:

1. In N/m: divide by 1,000.

   72.8 / 1,000 = 0.0728 N/m

2. In dyn/cm: the same number, since 1 mN/m = 1 dyn/cm.

   72.8 mN/m = 72.8 dyn/cm

Common conversions

Surface tension units

• Newton / meter (N/m): The force of one newton applied per meter length along the liquid surface. Newton per meter is the standard unit of surface tension.
  Conversion Factor: 1 N/m = 0.001 kN/m

• Kilonewton / meter (kN/m): The force of one kilonewton applied per meter length along the liquid surface.
  Conversion Factor: 1 kN/m = 1000 N/m

• Millinewton / meter (mN/m): The force of one millinewton applied per meter length along the liquid surface.
  Conversion Factor: 1 mN/m = 0.001 N/m

• Gram-force / centimeter (gf/cm): The force of one gram-force applied per centimeter length along the liquid surface.
  Conversion Factor: 1 gf/cm = 0.980665 N/m

• Dyne / centimeter (dyn/cm): The force of one dyne applied per centimeter length along the liquid surface.
  Conversion Factor: 1 dyn/cm = 0.001 N/m

• Erg / centimeter² (erg/cm²): The work done against surface tension per square centimeter in ergs.
  Conversion Factor: 1 erg/cm² = 0.001 N/m

• Erg / millimeter² (erg/mm²): The work done against surface tension per square millimeter in ergs.
  Conversion Factor: 1 erg/mm² = 100 erg/cm² = 0.1 N/m

• Poundal / inch (pdl/in): The force of one poundal applied per inch length along the liquid surface.
  Conversion Factor: 1 pdl/in = 5.4431 N/m

• Pound-force / inch (lbf/in): The force of one pound-force applied per inch length along the liquid surface.
  Conversion Factor: 1 lbf/in = 175.1268 N/m