Chlorine Calculator Ppm

Pool Chlorine PPM Dosing Calculator

Calculate exactly how much chlorine to add to reach your target PPM.

Liquid: 10-12%, Granular: 65%

Required Dosage

Understanding Chlorine PPM Calculations

Maintaining the correct Parts Per Million (PPM) of chlorine is essential for pool safety and water clarity. This chlorine calculator helps you determine the exact weight or volume of chlorine product needed based on the active strength of your chemical (Sodium Hypochlorite for liquid or Calcium Hypochlorite for granular).

How to Use the Calculator

• Pool Volume: Enter the total capacity of your pool in gallons.
• Chlorine Concentration: Check your chemical label. Liquid chlorine is typically 10% to 12.5%. Granular shock is often 65% to 73%.
• PPM Levels: Standard residential pools should maintain 1-3 PPM. If you are "shocking" the pool, your target might be 10-20 PPM depending on Cyanuric Acid levels.

The Formula Behind the Math

The math used to calculate chlorine dosing is based on the weight of water. Since 1 gallon of water weighs approximately 8.34 pounds, we use the following formula:

Dosage (lbs) = (Volume × 8.34 × PPM Increase) / (Concentration % / 100 × 1,000,000)

Quick Reference Dosage Table

Pool Size	To raise 1 PPM (10% Liquid)	To raise 1 PPM (65% Granular)
5,000 Gallons	6.4 fl oz	1.0 oz
10,000 Gallons	12.8 fl oz	2.1 oz
20,000 Gallons	25.6 fl oz	4.1 oz

function calculateChlorine() { var volume = parseFloat(document.getElementById('poolVolume').value); var strength = parseFloat(document.getElementById('chlorineStrength').value); var current = parseFloat(document.getElementById('currentPPM').value); var target = parseFloat(document.getElementById('targetPPM').value); var resultDiv = document.getElementById('chlorineResult'); var dosageOutput = document.getElementById('dosageOutput'); var secondaryOutput = document.getElementById('secondaryOutput'); if (isNaN(volume) || isNaN(strength) || isNaN(current) || isNaN(target) || strength <= 0 || volume <= 0) { alert("Please enter valid positive numbers for all fields."); return; } var ppmIncrease = target – current; if (ppmIncrease <= 0) { dosageOutput.innerHTML = "0 oz"; secondaryOutput.innerHTML = "Your current PPM is already at or above the target."; resultDiv.style.display = "block"; return; } // Formula: (Volume * 8.34 * Increase) / (1,000,000 * (Strength/100)) // This gives lbs. var strengthDecimal = strength / 100; var requiredLbs = (volume * 8.34 * ppmIncrease) / (1000000 * strengthDecimal); var requiredOz = requiredLbs * 16; resultDiv.style.display = "block"; if (strength = 16) { var lbs = (requiredOz / 16).toFixed(2); dosageOutput.innerHTML = lbs + " lbs"; secondaryOutput.innerHTML = "Equal to " + requiredOz.toFixed(2) + " dry ounces."; } else { dosageOutput.innerHTML = requiredOz.toFixed(2) + " oz"; secondaryOutput.innerHTML = "Measure by weight for granular chlorine."; } } }