A density converter translates between metric and imperial density units. Density is mass per unit volume — how much matter is packed into a given space. Water (1 g/cm³ or 1000 kg/m³) is the standard reference point for specific gravity calculations.
Density Converter
Common Material Densities
| Material | kg/m³ | g/cm³ | lb/ft³ |
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How to Convert Density Units
Density unit conversion is commonly needed in materials science, engineering, cooking, and chemistry. The SI unit of density is kg/m³, but g/cm³ is often more practical for everyday materials since water = 1 g/cm³ — a convenient reference.
Step 1: Key Conversion Factors
1 g/cm³ = 1000 kg/m³ = 62.428 lb/ft³ = 0.036127 lb/in³ = 8.3454 lb/gal (US). Water density: exactly 1 g/cm³ at 4°C, or approximately 0.998 g/cm³ at room temperature (20°C). For most practical purposes, use 1 g/cm³ for water.
Step 2: Calculating Specific Gravity
Specific gravity = material density / water density. For materials measured in g/cm³, specific gravity equals the density number directly (since water = 1). Gold at 19.32 g/cm³ has specific gravity 19.32. This means gold is 19.32 times denser than water. Materials with SG less than 1 float; greater than 1 sink.
Step 3: Converting Between Mass and Volume
Knowing density lets you convert between mass and volume: mass = density × volume. Example: 1 cubic meter of steel (7850 kg/m³) has mass of 7850 kg. A pint of honey (473 mL, density ~1.4 g/mL) weighs about 662 grams — heavier than a pint of water (473 g). This is why "a pint's a pound" only works for water, not all liquids.
FAQ
How do I convert kg/m³ to g/cm³?
Divide kg/m³ by 1000 to get g/cm³. Example: water is 1000 kg/m³ = 1 g/cm³. Since 1 m³ = 1,000,000 cm³ and 1 kg = 1000 g, the conversion factor is exactly 1000. So 7850 kg/m³ (steel) = 7.85 g/cm³.
What is specific gravity?
Specific gravity is the ratio of a material's density to the density of water (1 g/cm³ = 1000 kg/m³). It is dimensionless. Specific gravity greater than 1 means the material sinks in water; less than 1 means it floats. Example: oak wood has specific gravity ~0.75 (floats), steel has ~7.85 (sinks).
What is the density of water in different units?
Water at 4°C (maximum density): 1000 kg/m³ = 1 g/cm³ = 1 g/mL = 62.428 lb/ft³ = 0.03613 lb/in³ = 8.345 lb/gal (US). At room temperature (20°C), water is slightly less dense at 998.2 kg/m³.
How is density measured in cooking?
In cooking and food science, density is often expressed in g/mL (equivalent to g/cm³). Water is 1 g/mL. Vegetable oil is about 0.92 g/mL (floats on water). Honey is about 1.4 g/mL. Knowing ingredient density lets you calculate mass from volume measurements.
Is this density converter free?
Yes, completely free with no signup required. All conversions run instantly in your browser.