Density Converter - Mass per Volume Units Online

Density describes how much mass fits in a unit of volume—think kilograms per cubic metre for SI, or pounds per cubic foot in US engineering. This converter normalizes every choice through kilograms per cubic metre (kg/m³) so you can jump between metric, US customary, and specialized units without looking up factors by hand.

Supported units

SI and common metric: kg/m³, g/cm³, g/mL, kg/L, g/m³, metric tonnes per m³.
US customary: lb/ft³, lb/in³, oz/in³.
Engineering: slugs per cubic foot (slug/ft³).

How conversions work

Each unit has a fixed factor to kg/m³ based on standard definitions of the pound, inch, foot, slug, and metric tonne. Your input value is multiplied by the source factor to get kg/m³, then divided by the target factor. High-precision arithmetic is rounded for display but suitable for everyday science and engineering estimates.

When to double-check

For legal metrology, custody transfer, or safety-critical calculations, always verify against official standards and use calibrated measurements. Screen tools are convenient but do not replace documented procedures or certified instruments.

Frequently Asked Questions

Is g/cm³ the same as g/mL?

Yes, for practical purposes: one cubic centimetre is one millilitre, so the numeric density is identical in those two units.

Which pound definition do you use?

International avoirdupois pound tied to the kilogram definition used with SI.

Can I convert dynamic viscosity here?

No—this tool is strictly mass per volume (density). Viscosity uses different units such as Pa·s or cP.

Why show kg/m³ in the details panel?

It is the common SI reference density, helpful when you want to compare two conversions or copy a SI value into another worksheet.