Conductivity to TDS Calculator
Estimate total dissolved solids (TDS) from conductivity, or the conductivity expected for a given TDS, using a conversion factor that suits your water.
- TDS = k × EC = 0.65 × 800 = 520 mg/L
Conductivity to TDS
k depends on the dissolved ions: about 0.5 for sodium chloride, 0.55 to 0.7 for most natural waters (0.65 is a common default) and up to about 0.8 for some industrial waters. Calibrate k against a gravimetric TDS test for best results.
Worked example
Water reading 800 µS/cm with k = 0.65 contains about 520 mg/L of dissolved solids.
Frequently Asked Questions
How do I convert µS/cm to ppm?
Multiply by a TDS factor, typically 0.5 to 0.7. With 0.65, 1000 µS/cm is about 650 ppm.
Is TDS the same as conductivity?
No. Conductivity measures how well water conducts; TDS is the mass of dissolved solids, which is estimated from conductivity.
Does TDS include non ionic substances?
A gravimetric TDS does, but a conductivity based estimate only sees dissolved ions.
Learn more on the blog
Electrical conductivity explained
A practical, field focused guide on instrumentationblog.in that explains the theory behind this calculator and how engineers apply it on real plants.
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