Enter the EC value in mS/cm and select the conversion scale to determine the approximate ppm value, or use the formula and conversion table below to verify the result.
- us/cm to ppm Converter
- ng/mg to ppm Converter
- G/L To Mmol/L Calculator
- Meq To Mg Calculator
- All Unit Converters
EC to PPM Formula
The following formula is used to convert electrical conductivity in mS/cm to an approximate total dissolved solids value in ppm.
ppm = EC \times factor
The inverse formula is:
EC = ppm / factor
Variables:
- ppm is the approximate dissolved solids concentration in parts per million
- EC is the electrical conductivity in mS/cm
- factor is the conversion scale used by the meter, commonly 500, 640, or 700
To calculate ppm from EC, multiply the EC reading by the scale factor used by your meter. For example, on the 500 scale, 1.0 mS/cm is approximately 500 ppm.
What is EC to PPM Conversion?
EC to ppm conversion is a way of estimating the concentration of dissolved solids in a solution based on its electrical conductivity. Electrical conductivity measures how well a solution carries electrical current, while ppm is used as a practical estimate of how much dissolved material is present. Because the relationship is based on calibration standards rather than a single fixed physical constant, different meters may use different conversion scales such as 500, 640, or 700.
How to Calculate EC to PPM?
The following steps outline how to calculate ppm from an EC reading.
- First, determine the EC reading in mS/cm.
- Next, identify which conversion scale your meter uses, such as 500, 640, or 700.
- Multiply the EC value by the selected factor using the formula ppm = EC × factor.
- After calculating the result, compare your answer with the converter above.
Example Problem:
Use the following variables as an example problem to test your knowledge.
EC = 1.4 mS/cm
Conversion Factor = 700
ppm = 1.4 × 700 = 980 ppm
EC to PPM Conversion Table
The table below shows example conversions for an EC of 1.0 mS/cm using common scale factors.
| Conversion Scale | Factor (ppm per mS/cm) | 1.0 mS/cm in ppm |
|---|---|---|
| 500 scale (NaCl) | 500 | 500 ppm |
| 640 scale | 640 | 640 ppm |
| 700 scale (442) | 700 | 700 ppm |
Using the correct factor is important because the same EC reading can produce different ppm values depending on the calibration scale selected by the meter. Matching the factor in the calculator to your device will help keep your converted ppm values consistent with your meter's readings.