Density Units and Conversions: Complete Guide with Conversion Factors

Common Density Units

Density can be expressed in many different units. The most common are:

Unit	Symbol	Common Use	Example
Grams per Milliliter	g/mL	Laboratory, chemistry	Water = 1.0 g/mL
Grams per Cubic Centimeter	g/cm³	Physics, materials science	Gold = 19.3 g/cm³
Kilograms per Cubic Meter	kg/m³	SI unit, engineering	Water = 1000 kg/m³
Pounds per Cubic Foot	lb/ft³	US engineering, construction	Water = 62.4 lb/ft³
Pounds per Cubic Inch	lb/in³	Manufacturing, precision engineering	Steel ≈ 0.284 lb/in³

Each Unit Explained

g/mL (Grams per Milliliter)

Most common in chemistry labs

1 g/mL = 1 g of substance in 1 mL of volume
Water's density: exactly 1.0 g/mL (by definition at 4°C)
Used for liquids and small solids
Example: Oil ≈ 0.92 g/mL, Mercury ≈ 13.6 g/mL

g/cm³ (Grams per Cubic Centimeter)

Equivalent to g/mL

1 cm³ = 1 mL, so g/cm³ = g/mL numerically
Used interchangeably with g/mL
Common in solid material measurements
Example: Aluminum = 2.7 g/cm³

kg/m³ (Kilograms per Cubic Meter)

SI (International System) unit

Official scientific standard
1 kg/m³ = 0.001 g/mL
Used in engineering and physics
Example: Air at sea level ≈ 1.2 kg/m³

lb/ft³ (Pounds per Cubic Foot)

Common in US engineering

Used in construction and industrial applications
1 lb/ft³ ≈ 16 kg/m³
Water = 62.4 lb/ft³
Example: Concrete ≈ 150 lb/ft³

lb/in³ (Pounds per Cubic Inch)

Precision manufacturing

Used for very dense materials or small objects
1 lb/in³ ≈ 27,680 kg/m³
Steel ≈ 0.284 lb/in³
Lead ≈ 0.41 lb/in³

Conversion Factors

Use these factors to convert between units:

From	To	Multiply By
g/mL	kg/m³	× 1000
kg/m³	g/mL	÷ 1000
g/cm³	kg/m³	× 1000
g/mL	lb/ft³	× 62.4
lb/ft³	g/mL	÷ 62.4
g/mL	lb/in³	× 0.036
lb/in³	g/mL	÷ 0.036
kg/m³	lb/ft³	÷ 16.02

How to Convert Between Units

Step-by-Step Process

Identify your starting unit and target unit
Find the conversion factor from the table above
Multiply your density value by the conversion factor
Write the result with the new unit

Example Conversions

Convert 2.7 g/cm³ to kg/m³:

2.7 g/cm³ × 1000 = 2700 kg/m³

Convert 1000 kg/m³ to g/mL:

1000 kg/m³ ÷ 1000 = 1.0 g/mL

Convert 0.92 g/mL to lb/ft³:

0.92 g/mL × 62.4 = 57.4 lb/ft³

More Conversion Examples

Aluminum Density Conversions

Aluminum density = 2.7 g/cm³

In kg/m³: 2.7 × 1000 = 2700 kg/m³
In lb/ft³: 2.7 × 62.4 = 168.5 lb/ft³
In lb/in³: 2.7 ÷ 27.68 = 0.098 lb/in³

Water Density Conversions

Water density = 1.0 g/mL

In kg/m³: 1.0 × 1000 = 1000 kg/m³
In lb/ft³: 1.0 × 62.4 = 62.4 lb/ft³
In g/cm³: 1.0 g/mL = 1.0 g/cm³

Mercury Density Conversions

Mercury density = 13.6 g/mL

In kg/m³: 13.6 × 1000 = 13,600 kg/m³
In lb/ft³: 13.6 × 62.4 = 848.6 lb/ft³
In g/cm³: 13.6 g/mL = 13.6 g/cm³

Quick Reference: Material Densities in Different Units

Material	g/mL	kg/m³	lb/ft³
Water	1.0	1,000	62.4
Aluminum	2.7	2,700	168.5
Iron	7.87	7,870	491
Copper	8.96	8,960	559
Gold	19.3	19,300	1,204
Oil	0.92	920	57.4
Mercury	13.6	13,600	848.6
Cork	0.24	240	15

Summary

g/mL and g/cm³ are equivalent (most common in labs)
kg/m³ is the SI standard unit
lb/ft³ is common in US and engineering
Remember: 1 g/mL = 1000 kg/m³ = 62.4 lb/ft³
Use the conversion factors above for quick calculations
Or use our calculator for automatic conversions

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