Chemical Dosing Calculator

About the Chemical Dosing Calculator

Water treatment dosing: the mass of chemical (in grams) to add equals the target dose (mg/L) times the water volume (litres), divided by 1000. Purity adjusts for active strength.

How to use this calculator

1. Enter the target dose in \(mg/L\).
2. Enter the water volume in \(L\).
3. The calculator multiplies dose by volume, then divides by \(1000\) to convert from milligrams to grams.
4. Check the result and make sure your units match the situation, especially if your volume is in \(m^3\) or gallons.

The formula explained

The formula computes the mass of chemical needed in grams when the dose is given in \(mg/L\) and the water volume is given in \(L\). The division by \(1000\) converts the result from milligrams to grams.

• dose = target concentration in \(mg/L\)
• volume = amount of water in \(L\)
• mass = chemical mass needed in \(g\)

Step by step method

1. Multiply the dose in \(mg/L\) by the water volume in \(L\).
2. Divide the result by \(1000\) to convert milligrams to grams.
3. State the final mass with the correct unit, \(g\).

Worked example

Problem. You need to dose \(2.5\\,mg/L\) into \(800\\,L\) of water. How much chemical do you need?

1. Compute \(2.5 \\times 800 = 2000\) \(mg\).
2. Convert to grams, \(2000 / 1000 = 2\) \(g\).
3. The required mass is \(2\\,g\).

Tips and common mistakes

• Make sure the volume is in \(L\). If you have \(m^3\), convert first using \(1\\,m^3 = 1000\\,L\).
• Do not forget the \(1000\) conversion, because the dose is in milligrams per liter but the final mass is usually reported in grams.

Frequently asked questions