Gas Conversion Workspace
Convert a declared ideal reference volume of any of the 29 pinned pure gases into amount of substance and mass. Enter the reference pressure and temperature explicitly, then choose the identified gas from the catalog. The calculation is performed locally in your browser.
FreeNo sign-upPrivate — runs in your browser, nothing is uploaded
Ideal-reference conversion (Z = 1). Pressure is absolute; temperature is kelvin.
Visible default basis: 0 °C · 101.325 kPa(a) · dry · ideal reference equivalent.
29 of 29 pinned launch substances shown. Search narrows this catalog only; it does not identify a new material.
Quick answer
A reference gas volume cannot be converted to mass without a stated reference pressure, temperature and gas identity. This tool uses n = PV/(ZRT) with Z = 1 for its ideal-reference result, then applies the listed conventional molar mass. It keeps the reference basis visible so the result can be checked or reproduced.
Formula & method
n = PV / (RT); mass = n × M
- P — absolute reference pressure in pascals
- V — reference volume in cubic metres
- T — absolute reference temperature in kelvin
- R — 8.31446261815324 J/(mol·K)
- M — declared gas molar mass in kg/mol
Ideal-reference only. It does not claim a real-fluid density or phase result.
Examples
- Input
- 100 m³ N₂ at 101,325 Pa and 273.15 K
- Result
- 4,461.503 mol and 124.982 kg
- Why
- The tool first finds amount from the declared state, then multiplies by nitrogen's 0.0280134 kg/mol conventional molar mass.
- Input
- 10 m³ CO₂ at 101,325 Pa and 293.15 K
- Result
- Amount and mass at the entered basis
- Why
- Changing the reference temperature changes the amount represented by the same labelled volume; the basis remains in the result panel.
- Input
- 25 m³ H₂ at 101,325 Pa and 273.15 K, output lb
- Result
- Moles, kilograms and pounds
- Why
- The pounds value is converted from calculated kilograms using the exact international pound definition.
When to use this tool
- Preparing an ideal reference-volume mass estimate with a stated gas identity.
- Checking a supplier quantity that already declares its reference pressure and temperature.
- Converting between moles, kilograms and pounds before selecting a real-fluid workflow.
Common mistakes
- Entering a gauge pressure as though it were an absolute reference pressure.
- Treating Nm³, Sm³ and actual m³ as identical without declaring their reference state.
- Using the ideal result as a cylinder inventory or liquid quantity at high pressure.
Assumptions
What the result takes for granted:
- The entered pressure is absolute and temperature is absolute.
- The reference-gas calculation uses compressibility factor Z = 1.
- Molar masses are conventional rounded values from the listed source records, not an assay certificate.
Limitations
Where this tool stops — and what to use instead:
- This initial view does not calculate real-fluid density, phase, liquid inventory, mixture properties or cylinder residuals.
- All 29 catalog gases are available for this ideal-reference conversion; the separate real-fluid workflow deliberately supports a smaller admitted model matrix.
- Safety-critical engineering, filling and custody-transfer decisions require the applicable standards, instrument data and qualified review.
Frequently asked questions
Why do I have to enter pressure and temperature?
A gas volume represents a different amount at a different pressure or temperature. The visible reference state prevents an ambiguous mass conversion.
Is Nm³ always the same as Sm³?
No. Both labels are used with different reference conventions. Enter the actual pressure and temperature specified by your document instead of assuming a universal definition.
Does this calculate real-gas compressibility?
No. This view explicitly uses Z = 1. A real-fluid result must be capability-verified rather than inferred from this answer.
Which molar mass does the tool use?
It uses the conventional molar mass stored for the gas and identifies the gas in the result.
Can I use a negative pressure?
No. An absolute pressure cannot be negative. Gauge pressure requires a separate atmospheric-pressure context.
Sources & references
External references open in a new tab. We are independent and not affiliated with these organizations.
- ✓ Free to use
- ✓ No sign-up required
- ✓ Runs entirely in your browser — nothing is uploaded.
- ✓ Formula and method shown above
Provided “as is” for general information only — results may be inaccurate, so verify before you rely on them. No warranty; use at your own risk.
Built and reviewed by HIFreeTools against the formula shown above and any authoritative references cited on this page. See our methodology and editorial standards.
Related tools
- Ideal Gas Law CalculatorScience & Engineering
- Combined Gas Law CalculatorScience & Engineering
- Mole CalculatorScience & Engineering
- Pressure CalculatorScience & Engineering
- Gas Batch CalculatorGas
- Gas Reference ConditionsGas
- Gas and Liquid EquivalentsGas
- Gas Flow & RuntimeGas
- Gas Mixture AnalysisGas
- Gas Cylinder InventoryGas
Embed this tool on your site
Free to embed, no sign-up. Paste this code where you want the gas conversion workspace to appear: