Convert molecular data into reliable density estimates. Use gas law inputs or direct molar volume. Export results, inspect formulas, and verify examples with ease.
Gas mode uses pressure, temperature, and Z. Condensed mode uses molar volume. For liquids and solids, molecular weight alone is not enough.
| Sample | Mode | Molecular Weight | Pressure | Temperature | Molar Volume | Z | Density |
|---|---|---|---|---|---|---|---|
| Oxygen | Ideal gas | 32.00 g/mol | 1 atm | 0 °C | — | 1.00 | 1.429 g/L |
| Carbon dioxide | Ideal gas | 44.01 g/mol | 1 atm | 25 °C | — | 1.00 | 1.799 g/L |
| Nitrogen | Ideal gas | 28.014 g/mol | 2 atm | 20 °C | — | 1.00 | 2.329 g/L |
| Ethanol | Condensed phase | 46.07 g/mol | — | — | 58.4 mL/mol | — | 0.789 g/mL |
| Benzene | Condensed phase | 78.11 g/mol | — | — | 89.4 mL/mol | — | 0.874 g/mL |
ρ = (P × M) ÷ (Z × R × T)
ρ is density, P is absolute pressure, M is molecular weight, Z is compressibility factor, R is the gas constant, and T is absolute temperature.
ρ = M ÷ Vm
ρ is density, M is molecular weight, and Vm is molar volume. This is suitable when you know the liquid or solid molar volume.
Molecular weight and density are related, but context matters. Gases respond strongly to pressure and temperature. Liquids and solids depend on packing and molar volume. This calculator handles both cases in one place. It reduces manual conversion work. It also helps students, lab staff, and process engineers review assumptions quickly.
In gas mode, the tool uses the ideal gas density equation. Molecular weight supplies mass per mole. Pressure sets how much gas fits into a given space. Temperature changes particle spacing. The optional compressibility factor, Z, corrects the ideal model when real gas behavior matters. When Z equals one, the gas is treated as ideal. This is reasonable for many classroom and low pressure problems.
In condensed phase mode, density cannot come from molecular weight alone. A second property is needed. This calculator uses molar volume. Molar volume describes how much space one mole occupies. Dividing molecular weight by molar volume gives density. This approach is useful for liquids, melted materials, and some solid estimates when molar volume data is available from references or experiments.
Unit control is important in chemistry. Pressure may be entered in atmospheres, kilopascals, bar, pascals, or psi. Temperature may be entered in kelvin, Celsius, or Fahrenheit. Molar volume can be entered in milliliters, liters, cubic centimeters, or cubic meters per mole. The result can be reviewed in grams per liter, kilograms per cubic meter, or grams per milliliter.
Use the calculator for gas storage checks, reaction planning, solvent review, and teaching. Always verify that gas pressure is absolute, not gauge pressure. For liquids and solids, use reliable molar volume values. Results are estimates unless measured data is used. Strong intermolecular forces, high pressure, and nonideal behavior can change real density in practice.
The extra outputs support faster interpretation. Molar concentration shows how many moles are present per liter in gas mode. Specific volume shows the space occupied by each gram. These values help with vessel sizing, feed calculations, and conversion checks. They also make it easier to compare compounds under the same conditions without rewriting the equation each time.
For mixtures, this tool is best used with average molecular weight and a suitable Z value or mixture molar volume. That gives a screening estimate. Critical design work should still rely on measured density, validated equations of state, or trusted process data. Used correctly, this calculator is a fast and practical chemistry reference.
No. You also need state information. Gases need pressure and temperature. Liquids and solids need another property, such as molar volume or measured packing behavior.
The calculator uses ρ = (P × M) ÷ (Z × R × T). It is based on the ideal gas law and can include a compressibility factor for real gas correction.
Z adjusts the ideal gas result when the gas behaves nonideally. This becomes more important at higher pressures or when intermolecular effects are stronger.
Liquid and solid density depends on how molecules occupy space. Molar volume provides that space term. Without it, density cannot be estimated from molecular weight alone.
Use absolute pressure in gas mode. Gauge pressure will give the wrong density unless you first convert it to absolute pressure.
g/L is common for gases. g/mL is common for liquids. kg/m³ is useful for engineering comparisons and matches g/L numerically.
Yes, for screening work. Use an average molecular weight and a suitable Z value or mixture molar volume. For critical work, confirm with measured data.
No. They are estimates based on the model and the data entered. Real systems can differ because of pressure effects, temperature effects, and intermolecular interactions.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.