Conductivity converter
Convert between µS/cm and S/m, the units on every water quality meter, and see the rough TDS that goes with it.
That's about the same as tap water. That is roughly 250 ppm of dissolved solids.
What it means
How conductive is that?
The TDS estimate uses the common 0.5 factor. Real meters use 0.5 to 0.7 depending on which salts dominate.
Every unit
Your conductivity in every unit
Learn
Three things worth knowing
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TDS ≈ µS/cm ÷ 2
A 500 µS/cm reading is roughly 250 ppm of dissolved solids. Cheap "TDS pens" measure conductivity and do exactly this division.
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The mho, spelled backwards
Conductance used to be measured in mhos, ohm reversed, with an upside-down omega for a symbol. SI replaced it with the siemens in 1971.
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Conductivity is not purity
It only detects charged particles. Sugar, oil and many organic contaminants barely register, so a low reading does not mean water is safe.
Shortcuts
Popular conductivity conversions
Background
About conductivity units
Conductivity is the inverse of resistivity, in siemens per meter. Water testing uses µS/cm, because pure water sits near 0.055 µS/cm and tap water around 500.