Ozone Formulas and Conversions

Accurate ozone calculations are essential for proper system design, performance verification, and safe operation. This technical reference compiles commonly used ozone output and concentration conversions.

On this page

Share This Article

Fundamental Properties of Ozone

Understanding the nature of the “activated oxygen” molecule is the first step in any ozone application.
Chemical Formula O3
Molecular Weight 48 g/mol
Gas Density at STP 2.14 kg/m3
Solubility in Water ~13x higher than Oxygen
Oxidation Potential 2.07 V

Common Ozone Measurement Units

Ozone is measured differently depending on whether it is in a gas or liquid phase.

Concentration Units (Gas & Liquid)

mg/L

Milligrams per Liter

Used for dissolved ozone in water.

g/m3

Grams per Cubic Meter

The standard for measuring ozone concentration in a gas stream.

PPM

Parts Per Million
  • 1 ppm is approximately 1 mg/L.
  • In air: 1 ppm by volume is 2.14 mg/m3.
% Weight

Common for generator specifications.

  • 1% by weight in Air = 12.8 g/m3
  • 1% by weight in Oxygen = 14.3 g/m3

Flow Rate Units

LPM

Liters Per Minute

Standard metric for gas flow (oxygen or air).

SCFH

Standard Cubic Feet per Hour

Standard imperial unit for gas flow.

m3/hr

Cubic Meters per Hour

Used for high-volume gas or water flow.
GPM Gallons Per Minute

Standard imperial unit for water flow.

Production & Pressure Units

g/hr

Grams per Hour

The standard measure of ozone generator output capacity.

lbs/day

Pounds per Day

Common in large-scale industrial ozone specs.
psi Pounds per Square Inch

Measure of back-pressure on the system.

Key Formulas & Conversions

Ozone Generator Output

Estimates generator output based on feed gas flow and concentration
Output (g/hr) = (Flow (LPM) × 60 × Dosage (g/m3)) ÷ 1000
Capacity is expressed as mass produced per unit time. Essential for equipment sizing and comparison.

1 g/hr = 24 g/day

1 lb/day = 18.9 g/hr
1 kg/hr = 2.2046 lb/hr
1 mg/hr = 0.001 g/hr

Ozone Dosage Rate

This tells you how big your ozone generator needs to be to treat a specific flow of water at a specific target level.
Required O3 (g/hr) = (Flow (GPM) × 3.785 × 60 × Dosage (PPM)) ÷ 1000

Ozone Concentration

The conversion changes based on whether you are feeding the generator with Air or Pure Oxygen because oxygen is heavier.

Ozone Concentration in Air by Weight

100 g/m3 = 7.8% O3

1% = 12.8 g/m3 O3
 1% = 7284 ppm O3

Ozone Concentration in Air by Weight

 100 g/m3 = 6.99% O3

1% = 14.3 g/m3 O3
1% = 6520 ppm O3

Ozone Concentration in Air by Volume

1 mg/L = 1 g/m3 = 1 µg/mL = 467 ppm O3

1 ppm = 2.14 mg/m3 O3
100 pphm = 1 ppm

Ozone Concentration in Water

 1 mg/L = 1ppm = 1 g/m3 O3 (by weight)

Discover More Pinnacle Insights

  • Blogs
    EPA’s Proposed Perchlorate Regulation: What It Means for Treatment Engineers and Oxidation Strategies
    A recent development in U.S. water regulation has significant implications for how utilities and engineers design treatment systems. The U.S. Environmental Protection Agency (EPA) has proposed a National Primary Drinking Water Regulation (NPDWR) for perchlorate, setting a Maximum Contaminant Level Goal (MCLG) and co-proposing enforceable Maximum Contaminant Levels (MCLs) of 20 µg/L, 40 µg/L, or 80 µg/L for perchlorate in drinking water. Perchlorate, used in rocket propellants, fireworks, flares, and found naturally in arid regions, has been under regulatory review for more than a decade due to potential health concerns, especially for sensitive [...]