Convert linear charge density between coulomb/metre, microcoulomb/metre and per-centimetre units.
Electricity • 5 units
All 5 units on the Linear Charge Density Converter are defined against the Coulomb/meter (C/m), so each result is one conversion factor away from a single reference rather than the end of a chain of roundings.
The conversion this page is most often opened for is ready before you type anything: 1 C/m = 1,000,000 µC/m. Change either side and every row in the table recalculates with it.
Everything runs in your browser — no account, no uploads, nothing leaves your device.
Two things about this table surprise people on first use. The first is scale: a coulomb per metre is an enormous charge density, and real charged lines are measured in nanocoulombs or microcoulombs per metre, so most practical values sit far down the table. The second is direction — coulombs per centimetre is a hundred times larger than coulombs per metre, not smaller, because shortening the length in the denominator concentrates the same charge into a shorter run.
The quantity becomes concrete through capacitance. A charged transmission line carries a linear charge density equal to its capacitance per unit length multiplied by the voltage across it, so a coaxial cable at roughly 100 pF/m held at 100 V carries about 10 nC/m along its inner conductor. That is the charge that has to be supplied every time the line is driven, and it is why a long cable behaves as a load on a driver even when nothing is connected at the far end.
The field around a line charge falls as 1/r rather than the 1/r² of a point charge, and the working form is E = λ ⁄ (2πε₀r). Putting a modest 1 µC/m one metre away gives about 18 kV/m — a substantial field from a small-sounding charge, and a reminder that the slow fall-off is what makes long charged objects hazardous at distances where a point charge of the same magnitude would be negligible. It is also the reason charged webs of film and paper on a fast production line produce discharges well away from the material itself.
Quick reference — 1 Coulomb/meter (C/m) is equal to:
| Millicoulomb/meter | mC/m | 1,000 |
| Microcoulomb/meter | µC/m | 1,000,000 |
| Coulomb/centimeter | C/cm | 0.01 |
| Coulomb/inch | C/in | 0.0253999992 |
5 units of linear charge density, each a fixed multiple of the C/m. The table spans 100,000,000:1, from µC/m (0.000001 C/m) to C/cm (100 C/m). Conversion is one multiplication into the base unit and one division out of it, with no lookup table and no approximation.
value_to = value_from × (factor_from ÷ factor_to)1 C/m = 1 C/m1 mC/m = 0.001 C/m1 µC/m = 0.000001 C/m1 C/cm = 100 C/m1 C/in = 39.3701 C/mwhere:
Assumptions: Factors are exact definitions. Full double precision is carried internally and rounding is applied only for display.
Result25 C/m = 25000000 µC/m
Linear charge density is charge per unit length, in coulombs per metre (C/m). It is the natural description whenever one dimension of a charged object dwarfs the other two — a wire, a cable core, a charged filament.
The reason it earns its own quantity is that the field around a long charged line falls off as 1/r, not the 1/r² of a point charge. That single difference sets the field between a conductor and its shield in coaxial cable, and therefore the cable's capacitance per metre and its impedance. Working in charge per unit length rather than total charge is what makes those results independent of how long the cable happens to be.