EC to TDS Calculator
The EC to TDS Calculator helps convert the Electrical Conductivity (EC) of water into Total Dissolved Solids (TDS). These measurements are commonly used in water testing, agriculture, hydroponics, and environmental monitoring.
EC is a measure of how well water conducts electricity, which depends on the amount of dissolved salts and minerals. TDS gives you an estimate of the total concentration of dissolved substances in the water, usually in parts per million (ppm) or milligrams per liter (mg/L). This calculator allows users to convert EC to TDS using a chosen conversion factor, making it easier to understand water quality and manage related systems.
This tool is especially helpful when your device only shows EC or if you’re dealing with water quality reports and need to estimate TDS without lab equipment.
Formula of EC to TDS Calculator
To calculate TDS from EC, use this formula:
TDS (ppm or mg/L) = EC (µS/cm) × Conversion Factor
Where:
- EC (µS/cm) = Electrical Conductivity of water, measured using a conductivity meter.
- TDS (ppm or mg/L) = Total Dissolved Solids in the water.
- Conversion Factor = A value that changes depending on the types of dissolved solids.
Typical Conversion Factors:
| Conversion Factor | Common Use Case |
|---|---|
| 0.5 | Water with mostly sodium chloride (table salt) |
| 0.64 | Mixed salts (average value used by many TDS meters) |
| 0.7 | Water with more calcium, magnesium, or other harder salts |
| 0.8 | High mineral content or industrial water |
Keep in mind that TDS is an estimate based on conductivity and the type of ions in the water. This is why the conversion factor is not the same for all cases.
Reference Table: EC to TDS Conversion (Quick Look)
| EC (µS/cm) | TDS @ 0.5 | TDS @ 0.64 | TDS @ 0.7 | TDS @ 0.8 |
|---|---|---|---|---|
| 100 | 50 ppm | 64 ppm | 70 ppm | 80 ppm |
| 250 | 125 ppm | 160 ppm | 175 ppm | 200 ppm |
| 500 | 250 ppm | 320 ppm | 350 ppm | 400 ppm |
| 1000 | 500 ppm | 640 ppm | 700 ppm | 800 ppm |
| 1500 | 750 ppm | 960 ppm | 1050 ppm | 1200 ppm |
| 2000 | 1000 ppm | 1280 ppm | 1400 ppm | 1600 ppm |
Use this table for quick estimates if you’re dealing with standard EC readings. Always check the type of water to choose the correct factor.
Example of EC to TDS Calculator
Let’s say you have an EC reading of 850 µS/cm and want to calculate the TDS:
Using Different Conversion Factors:
- At 0.5:
TDS = 850 × 0.5 = 425 ppm - At 0.64:
TDS = 850 × 0.64 = 544 ppm - At 0.7:
TDS = 850 × 0.7 = 595 ppm - At 0.8:
TDS = 850 × 0.8 = 680 ppm
Which one should you use?
- For natural or drinking water, 0.5 or 0.64 is common.
- For water with a higher mineral load, 0.7 or 0.8 may be more accurate.
Most Common FAQs
Most commercial TDS meters use a factor of 0.64 as it provides a good average for mixed ion content in water. However, it’s always better to check the water source and adjust if needed.
The electrical conductivity depends on the type of dissolved solids, and different ions conduct electricity differently. Sodium chloride behaves differently than calcium or magnesium salts, so the factor changes to give a better TDS estimate.
Not exactly. TDS measures the amount of dissolved solids, but it doesn’t tell you what those solids are. Some minerals might be harmless or even beneficial, while others could be harmful. Water purity also considers contaminants like bacteria, which TDS doesn’t measure.