Density Converter
Convert between kg/m³, g/cm³, g/L, lb/ft³, and other density units.
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How to use this calculator
- 1
Enter the density value you want to convert.
- 2
Select the unit you are converting from (e.g. kg/m³).
- 3
Select the target unit (e.g. g/cm³).
- 4
The result appears instantly.
Frequently asked questions
Which density units does the converter cover?
Kilograms per cubic metre, grams per cubic centimetre, kilograms per litre, grams per litre, grams per millilitre, pounds per cubic foot, pounds per cubic inch and ounces per US gallon. The base is kg/m³.
Why are g/cm³, kg/L and g/mL all the same?
A litre is 1,000 cm³ and a millilitre is 1 cm³, so one gram per cubic centimetre is also one gram per millilitre and one kilogram per litre. All three equal 1,000 kg/m³. Likewise g/L equals kg/m³ exactly, which the tool shows by giving both a factor of 1.
What is the density of water in these units?
Near 4 °C pure water is about 1 g/cm³, or 1,000 kg/m³. In the tool that is 62.42796059 lb/ft³. It changes with temperature and with dissolved salts, so seawater and hot water differ slightly.
Are the pounds here mass or force?
Mass. Pounds per cubic foot means pound-mass per cubic foot, so 1 lb/ft³ is 16.01846337 kg/m³. Do not confuse it with weight density in lbf/ft³, which only matters when a structural or fluid calculation uses weight rather than mass.
Is density the same as specific gravity?
No. Specific gravity is a ratio to the density of water and has no unit, while density has units. As a quick link, a substance with a specific gravity of 2.7 has a density near 2.7 g/cm³, if water is taken as 1 g/cm³.
How precise are the imperial factors?
They use the exact relationships between the avoirdupois pound (0.45359237 kg), the foot, the inch and the US gallon: 1 lb/ft³ is 16.01846337 kg/m³, 1 lb/in³ is 27,679.9047 kg/m³ and 1 oz/gal (US) is 7.4891517 kg/m³. Results are shown to about ten significant digits.
Does density depend on temperature and pressure?
Yes, especially for gases and liquids. Air near 1.225 kg/m³ is a sea-level reference figure for 15 °C, and warmer or higher air is less dense. The converter changes units only and applies no correction for conditions.
Can it convert between mass and volume?
Not directly. Density links the two, but this converter changes only the density units. To get mass, multiply density by volume in matching units, which you can do after converting here.
Density unit conversion for metric and imperial values
Mass divided by volume, in whichever units you have
Density is mass per unit volume, and the same material appears under many unit pairs. Chemists quote g/mL, engineers quote kg/m³, and US drawings use lb/ft³ or lb/in³. The base unit here is kg/m³, which also equals g/L numerically. The units g/cm³, g/mL and kg/L are identical to one another, and each equals 1,000 kg/m³.
| Value | g/cm³ | lb/ft³ |
|---|---|---|
| 1,000 kg/m³ (water) | 1 | 62.42796059 |
| 2,700 kg/m³ (aluminium) | 2.7 | 168.5554936 |
| 7,850 kg/m³ (carbon steel) | 7.85 | 490.0594906 |
| 1.225 kg/m³ (air, sea level) | 0.001225 | 0.076474252 |
Worked example: metals in imperial units
Aluminium at about 2.7 g/cm³ comes to 0.097543688 lb/in³, so a cubic inch weighs roughly a tenth of a pound. Gold at 19.3 g/cm³ equals 1,204.859639 lb/ft³. The listed densities are typical handbook values; alloys and tempers vary a little.
Worked example: the reverse direction
A part quoted at 0.5 lb/in³ is 13.83995235 g/cm³, and 1 lb/in³ is 27.6799047 g/cm³. For fluids, 1 oz/gal (US) is 7.4891517 g/L, a unit sometimes used for concentrations such as additives per gallon.
Typical pitfalls
Mixing up lb as mass and lbf as force, ignoring the difference between US and imperial gallons, and forgetting that readings change with temperature are the usual causes of mistakes. The ounce-per-gallon unit in this tool is the US avoirdupois ounce per US gallon. If a datasheet states conditions, such as 20 °C, apply those same conditions to the result. Water is a convenient benchmark: if a number above 1 g/cm³ appears for a liquid, it sinks in water, and below 1 it floats, provided the two do not mix. Always state the temperature alongside any density you record.
Using density figures in practice
Once the density is in matching units you can estimate mass from volume by multiplying, or find volume from mass by dividing. Keep the units consistent: 7.85 g/cm³ times 100 cm³ gives 785 g, while 7,850 kg/m³ times 0.0001 m³ gives 0.785 kg. Do this conversion first, then the arithmetic, to avoid mixing grams with kilograms. Remember that powders, foams and wood have a bulk density that differs from the density of the solid material.
Learn more from an authoritative source:
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →