Free calculator

EC ↔ ppm / TDS converter

Meters report either EC or a “ppm” that is just EC scaled by a standard. There is no single true conversion — it depends on the meter's scale, so always store which scale a ppm value came from.

Input

EC readingmS/cmMeter scale (ppm standard)Solution temperature (optional)°CCorrects a raw reading back to 25 °C. Leave blank if your meter auto-compensates.

Result

Converted on the selected meter scale

EC (at 25 °C)

1.80mS/cm

= 1,800 µS/cm = 1.80 dS/m

TDS / ppm on 500 scale

900ppm

Other scales: 900 (500) · 1,152 (640) · 1,260 (700) ppm

1000 ppm on a 500-scale meter is not 1000 ppm on a 700-scale meter. When you share or store a ppm number, record the scale alongside it — otherwise the value is ambiguous by up to 40%.

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