The core equation is the same density relationship used for solids:

If density is in g/mL and mass is in grams, dividing mass by density gives volume directly in mL.

Choose whether to solve for density, mass, volume or specific gravity. Select a liquid preset where available, enter temperature, and then enter the two known values. Reference presets are convenient, but critical work should use a property source appropriate to the exact composition and temperature.

Weigh a known volume of liquid after taring the container. Divide liquid mass in grams by volume in millilitres. Because 1 mL = 1 cm³, the numerical result is also the density in g/cm³.

Example

49.5 g occupying 50.0 mL gives 0.990 g/mL.

Use a clean container or calibrated pycnometer where appropriate. Record container tare, add a measured liquid volume, obtain the liquid mass by subtraction, and divide by volume. Repeat measurements when precision matters and control temperature because thermal expansion changes volume.

Mass-volume conversion is not universal; it depends on density. One hundred grams of water occupies roughly 100 mL near room temperature, while 100 g of a denser liquid occupies less volume and 100 g of a lighter liquid occupies more.

Specific gravity is dimensionless because it is a ratio. At common reference conditions, a liquid with SG 0.80 is about 80% as dense as the reference water value. State the reference temperature when precision matters.

Most liquids expand as temperature rises, so the same mass occupies more volume and density decreases. Water has unusual behavior near 4°C. Petroleum products, refrigerants and cryogenic liquids can require dedicated property correlations rather than a simple linear correction.

For ideal mixtures, a rough estimate can be made from component mass and total volume or from suitable mixing rules. Real solutions can contract or expand on mixing, so the true density may differ. Do not use a simple weighted average when process accuracy depends on non-ideal solution behavior.

Reference tables should always state conditions. Water, ethanol, oils, glycerin, fuels and concentrated solutions can differ substantially, and commercial products often contain mixtures rather than pure compounds. Use the searchable material table for orientation and primary property data for design.

Liquid CO₂, nitrogen, oxygen, ammonia and propane are strongly state-dependent. They deserve dedicated phase-aware calculations. The generic liquid tool intentionally does not pretend that one room-temperature lookup value covers cryogenic or saturated conditions.

Find density

A liquid sample has mass 78.9 g and volume 100 mL. Density is 0.789 g/mL.

Find volume

250 g of a liquid at 1.25 g/mL occupies 200 mL.

Find mass

500 mL of a liquid at 0.92 g/mL has mass 460 g.

Each example uses the same relationship; only the unknown changes.

A density-vs-temperature curve is more useful than a single point when the process spans a temperature range. A nearly straight trend over a narrow interval does not guarantee linear behavior over a wide range. Near freezing, boiling, phase transitions or very high pressures, use property data designed for those conditions.

Do not assume every liquid is “basically water,” do not use a room-temperature density for a hot process without checking sensitivity, and do not confuse specific gravity with g/mL unless the water reference and conditions justify the numerical shortcut. Dissolved solids can change density substantially even when the liquid still looks like water.