Enter Chemistry Data
Example Data Table
| Sample | EC µS/cm | Factor | Residue mg | Volume mL | Ion Sum mg/L | Approx TDS mg/L |
|---|---|---|---|---|---|---|
| Tap Water | 620 | 0.65 | 40 | 100 | 390 | 403 |
| Well Water | 1050 | 0.70 | 76 | 100 | 720 | 735 |
| RO Outlet | 80 | 0.55 | 5 | 100 | 45 | 46 |
Formula Used
Conductivity method: TDS = EC × conversion factor × dilution factor.
Temperature correction: corrected EC = measured EC ÷ [1 + 0.02 × (temperature - 25)].
Gravimetric method: TDS = dried residue mass × 1000 ÷ sample volume.
Ion method: TDS = sum of measured dissolved ions in mg/L.
Hardness estimate: hardness as CaCO3 = calcium × 2.497 + magnesium × 4.118.
How to Use This Calculator
- Select the method that matches your available chemistry data.
- Enter conductivity, residue, ion, temperature, and dilution values.
- Use a conversion factor between 0.55 and 0.75 for many waters.
- Enter a target limit if you want a pass or warning result.
- Press calculate to view the result above the form.
- Use CSV or PDF buttons to save your report.
About TDS Calculation in Chemistry
What TDS Means
Total dissolved solids show the combined mineral load in water. The value includes salts, metals, carbonates, bicarbonates, and many other dissolved ions. It is normally reported as milligrams per liter. The same number is also called parts per million for dilute water. A TDS result does not name each chemical. It gives a useful total picture.
Why This Tool Helps
This calculator supports several chemistry routes. The conductivity route is fast. It uses electrical conductivity and a selected factor. The gravimetric route uses dried residue after evaporation. The ion route adds measured ions from laboratory analysis. The average option compares available methods and gives a balanced estimate.
Conductivity Based Testing
Conductivity is common in field work. Dissolved ions carry electric current. More ions usually mean higher conductivity. The conversion factor depends on water composition. Sodium chloride rich water may use one factor. Mixed mineral water may need another. Temperature also matters because warmer water conducts more current.
Laboratory Residue Method
The residue method is direct. A known sample volume is filtered, evaporated, dried, and weighed. The remaining mass represents dissolved and very fine retained solids. Good technique is important. Dirty dishes, wet residue, or wrong volume can change the answer.
Ion Sum Method
The ion sum method is useful when a lab report lists calcium, magnesium, sodium, potassium, chloride, sulfate, bicarbonate, and nitrate. Adding these ions gives a strong chemical estimate. Missing ions can make the result low. Duplicate alkalinity entries can make it high.
Reading the Result
Low TDS water may taste flat. Moderate values suit many uses. High values may cause scaling, taste issues, or irrigation concerns. Very high values need review before drinking, boiler feed, farming, aquariums, or process use. Always compare results with local standards and final laboratory advice.
FAQs
1. What is TDS in chemistry?
TDS means total dissolved solids. It estimates the combined amount of dissolved minerals, salts, and ions in water. It is usually reported in mg/L or ppm.
2. Is TDS the same as conductivity?
No. Conductivity measures electrical current carrying ability. TDS estimates dissolved solids. Conductivity can be converted to TDS by using a suitable factor.
3. Which conversion factor should I use?
Many water samples use 0.55 to 0.75. Use a factor that matches your water type or laboratory calibration. Mixed natural water often uses about 0.65.
4. Why does temperature affect TDS calculation?
Temperature changes conductivity. Warm water usually conducts more current. The calculator corrects EC toward 25°C before estimating TDS.
5. What is the gravimetric TDS method?
It uses a measured water volume. The sample is evaporated and dried. The remaining residue is weighed and converted to mg/L.
6. Can ion sum replace laboratory TDS?
Ion sum is useful when major ions are measured. It may miss untested dissolved substances. Use it as an estimate, not as a full certified report.
7. What is a good TDS value?
It depends on use. Drinking, irrigation, aquariums, boilers, and industrial systems need different limits. Always compare the result with the correct standard.
8. Why export CSV and PDF?
CSV helps spreadsheet review. PDF helps reporting, sharing, and record keeping. Both formats keep the main calculated values for later comparison.