Oxygen Partial Pressure Calculator

Formula used in this calculator

The calculator applies Dalton's law of partial pressures. For a gas mixture, the partial pressure of oxygen is proportional to its mole or volume fraction within the mixture.

• Step 1: Convert the total pressure to kilopascals (kPa) using the selected unit.
• Step 2: If water vapour pressure is provided, convert it to kPa and subtract it from the total pressure to obtain dry gas pressure.
• Step 3: Convert oxygen percentage to fraction if needed: F_O2 = percentage / 100.
• Step 4: Compute oxygen partial pressure: P_O2 = F_O2 × P_dry.
• Step 5: Convert P_O2 from kPa into atmospheres, bars, millimetres of mercury, and pounds per square inch.

This approach assumes ideal gas behaviour and is appropriate for most standard chemistry and teaching situations.

How to use this oxygen partial pressure calculator

1. Enter the measured total pressure of your gas mixture and select the correct unit.
2. Provide the oxygen concentration either as a fraction between zero and one or as a percentage.
3. Optionally, add water vapour pressure in the same unit as the total pressure to work with dry gas conditions.
4. Press the Calculate button to generate oxygen partial pressure in multiple unit systems.
5. Review the table to compare oxygen partial pressure values in kPa, atm, bar, mmHg, and psi.
6. Use the CSV or PDF download buttons to capture results for reports, lab books, or teaching materials.

Working with oxygen partial pressure in chemistry

Understanding oxygen partial pressure

Oxygen partial pressure describes how strongly oxygen contributes to the total pressure of a gas mixture. It is central for understanding combustion, respiration, and many laboratory gas experiments.

Dalton’s law and gas mixtures

According to Dalton’s law, the total pressure of a gas mixture equals the sum of individual gas partial pressures. When you know total pressure and oxygen fraction, you can easily calculate oxygen partial pressure.

Key input parameters in the calculator

The calculator accepts total pressure in several unit systems and oxygen concentration as a fraction or percentage. Optional water vapour pressure lets you work with dry gas pressure instead of the measured humid value.

Interpreting oxygen partial pressure results

Results show oxygen partial pressure in atmospheres, kilopascals, bars, millimetres of mercury, and pounds per square inch. Comparing these values helps you move confidently between laboratory instruments and theoretical calculations or textbook tables.

Using vapour pressure and humidity corrections

When moisture is present, water vapour occupies part of the total pressure. Subtracting vapour pressure before applying oxygen fraction gives a corrected dry oxygen partial pressure, important for high precision work and environmental or physiological studies.

Linking with other chemistry calculators

Many gas problems combine composition, vapour pressure, and molar properties. You can pair this tool with the Vapor Pressure from Antoine Calculator to estimate water vapour, then feed that value directly into the oxygen partial pressure calculation.

For gas composition studies, combine results with the Molar Mass of Gas Calculator. Together, these tools support deeper analysis of mixtures, diffusion behaviour, and real gas corrections across many chemistry scenarios.

Practical applications in study and laboratory work

Students can visualise how changing altitude, vessel pressure, or composition alters oxygen availability. In the laboratory, technicians quickly assess cylinder mixtures, reaction atmospheres, and safety margins. Careful use of the calculator encourages better experimental planning and clearer reporting of gas conditions.

Engineers working with compressed air or breathing gas systems can explore how storage pressure, regulator settings, and oxygen fraction interact. By adjusting parameters stepwise, you immediately see which combination delivers suitable oxygen levels for equipment performance or human exposure limits in industrial and laboratory environments.

Educators may also use prebuilt scenarios to challenge students. Ask them to match a target partial pressure by tuning fraction or total pressure, then compare their predictions with the calculator. This interactive approach strengthens intuition about gas laws and gives lasting confidence with real analytical data.

Students gradually recognise patterns linking pressure, composition, and temperature across many experimental gas systems worldwide.

Frequently asked questions