Density · Temp

Density at temperature calculator

Adjust liquid density for temperature. Pick a preset or enter custom values; the tool returns the density at the target temperature using the thermal expansion formula.

Last updated 2026-05-09. Math runs in your browser, no data leaves your computer.

General guidance only, not legal or professional engineering advice. Verify against the cited primary sources (IMDG, REACH, ChAFTA, RCEP, Customs Tariff Act, supplier SDS, etc.) before committing to a shipment, declaration, or contract. Sourzi assumes no liability for outcomes based on these calculators.

For ISO tank fill math, IMDG 4.2.1.9.5 sets the reference temperature at 50 degrees Celsius. For chargeable-weight calculations, use the temperature at the time of loading.

Density correction in chemical-trade context

Most chemical liquid cargo is quoted in tonnes (mass) but loaded in litres (volume). The bridge between the two is density, and density depends on temperature. A 24,000 L ISO tank loaded with caustic soda 50% at 25 degrees Celsius contains roughly 36,400 kg cargo; the same tank loaded at 50 degrees ambient (which the cargo can reach in transit through the Red Sea) contains roughly 36,000 kg, a 400 kg / 1.1% drop, because the liquid expanded.

For ISO tank fill calculations under IMDG 4.2.1.9.5, the reference temperature is 50 degrees Celsius. The tank must not be filled to a level where, at 50 degrees, the contents exceed the maximum fill volume specified for the cargo class. The density at 50 degrees feeds into that calculation; using density at 20 degrees over-estimates the cargo mass and risks violating the fill rule. Sourzi /tools/iso-tank-loading runs the full IMDG fill math for the most-shipped chemicals.

The thermal expansion formula is straightforward. Density at the target temperature equals reference density divided by 1 plus alpha times the temperature delta. Most liquids have alpha in the 0.0002 to 0.0012 per degree Celsius range. Light hydrocarbons (methanol, ethanol, gasoline) sit at the higher end (0.0010 to 0.0014); aqueous solutions (NaOH 50, citric 50) sit at the lower end (0.0004 to 0.0005); water itself is the lowest at 0.00021.

The alpha values used here are reference values for typical concentrations at typical temperatures; for precise work consult the supplier SDS or a chemistry handbook. The corrections are accurate within 1 to 2 percent across normal trade-temperature ranges (5 to 60 degrees Celsius).

Frequently asked

Why does density change with temperature?

Liquids expand when heated. The volume increases while the mass stays constant, so density (mass per volume) decreases. The thermal expansion coefficient alpha per liquid quantifies the slope. For caustic soda 50% solution alpha is around 0.00040 per degree Celsius; for sulphuric acid 0.00056; for methanol 0.00120; for water 0.00020.

When does the temperature correction matter for chemical trade?

When ISO tank loading at high or low ambient (IMDG 4.2.1.9.5 reference temperature is 50 degrees Celsius for fill calculations); when LCL air-freight where the tank is sealed in cargo hold above ambient; when high-density cargo where 1-percent density change is meaningful for chargeable weight billing; for thermal-expansion-prone cargo like methanol or LPG.

What is the formula?

density(T2) = density(T1) / (1 + alpha * (T2 - T1)). T1 is the reference temperature (often 20 degrees C); T2 is the temperature you want the density at; alpha is the thermal expansion coefficient.

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