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Oxygen Depletion Calculator

Estimate average oxygen concentration after nitrogen, argon, carbon dioxide, helium or another gas is released into a defined room.

Volume or mass inputTwo simplified room models19.5% oxygen reference

Define the room and release

Choose a simplified mixing model and release unit.

Screening estimate
Neither model predicts local pockets, stratification or ventilation flow paths.

Oxygen estimate

OSHA commonly defines below 19.5% oxygen as oxygen-deficient.

Estimated final oxygen—
Equivalent released volume—
Release / room ratio—
Estimated inert-gas fraction—
Review inputs

The result will be compared with a 19.5% oxygen reference.

This tool cannot approve entry into confined or enclosed spaces. Use a site procedure, ventilation assessment and actual atmospheric testing.
How the tool works

Screen oxygen-displacement scenarios carefully

The result is a room-average model and cannot predict local gas clouds, stratification or ventilation effects.

01

Convert the release

Mass inputs are converted to gas volume using the entered or preset density.

02

Choose a model

Equal-volume replacement and volume-addition models represent different simplified assumptions.

03

Compare with measurement

Use actual atmospheric testing for entry, work and rescue decisions.

Replacement modelFinal O₂ = initial O₂ × (1 − release volume ÷ room volume)
Addition modelFinal O₂ = initial O₂ × room volume ÷ (room volume + release volume)
Mass to volumeGas volume = released mass ÷ gas density
Reference sources: OSHA oxygen-deficient atmosphere definition OSHA interpretation of 19.5% oxygen. Always verify project-specific values against the applicable SDS, instrument manual, standard and site conditions.
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Frequently asked questions

Oxygen Depletion Calculator FAQ

Is 19.5% oxygen always a safe atmosphere?

No. It is a commonly used oxygen-deficiency threshold. Toxic, flammable and other hazards must also be evaluated.

Which model should I choose?

Use the model that best matches your screening assumption, then compare both. Neither replaces a dispersion or ventilation analysis.

Can gases form local oxygen-deficient pockets?

Yes. Density, temperature, release direction, obstacles and ventilation can produce local concentrations very different from the room average.

Can this approve confined-space entry?

No. Use a formal procedure and suitable atmospheric testing equipment.

Need help applying the result?

Share the target gas, range, environment, equipment format and project quantity to review relevant gas sensors, modules or complete detectors.

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