Surface charge density converter
Convert charge per area between C/m², µC/cm², e/nm² and esu/cm².
That's about the same as a battery electrode surface. That is one elementary charge for every 0.8011 nm².
What it means
How charged is that surface?
Figures are typical. A rubbed balloon varies with humidity; electrode values depend on the material and the voltage.
Every unit
Your surface charge in every unit
Learn
Three things worth knowing
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1 µC/cm² = 10 mC/m²
And one elementary charge per square nanometer is 0.16 C/m², or 16 µC/cm², typical of an electrode surface.
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Gauss’s law at a surface
The field just outside a charged conductor is the charge density divided by ε₀. That is what links a surface charge to a voltage, and why air breakdown sets a hard limit.
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Per cm² is 10,000 times per m²
A square meter holds 10,000 square centimeters. Mixing the two is the usual slip in electrochemistry papers.
Shortcuts
Popular surface charge conversions
Background
About surface charge density
Surface charge density is how much electric charge sits on each square meter of a surface. Static electricity lives in the microcoulombs per square meter; the charged layer on an electrode in a battery reaches tens of microcoulombs per square centimeter, ten thousand times more.
In air there is a ceiling: around 26.5 µC/m² the field reaches 3 MV/m and the air sparks.