Density Calculator
Enter two values and the calculator finds the third. The grayed field is the result.
Density:
The same density in other units:
Closest material:
Floats or sinks:
Calculation:
This density calculator finds the density, mass or volume of an object from the other two values. It takes g, kg, mg, lb and oz for mass, cm³, mL, L, m³, ft³, in³ and US gallons for volume, and gives density in g/cm³, kg/m³, g/mL, kg/L and lb/ft³.
It also compares the result with a table of common materials and draws a beaker of liquid so you can see whether the object floats or sinks, and how much of it sits below the surface.
How to use the density calculator
Step 1: Choose what you want to find: density, mass or volume. The result field turns gray.
Step 2: Enter the other two values and pick the unit of each. You can use a decimal point or comma.
Step 3: Click Calculate or press Enter. The result comes out in the unit selected in its field.
Step 4: Pick the liquid in the beaker (water, seawater, olive oil or mercury) to see whether the object floats or sinks. The drawing is not to scale: it shows the submerged share.
Density formula
Density is the mass in each unit of volume:
| ρ = m ÷ V |
Solving for the other two:
| m = ρ × V, V = m ÷ ρ |
An object floats if its density is lower than the liquid, and the share that sits underwater is the ratio of the two densities:
| submerged share = object ρ ÷ liquid ρ |
If the ratio is 1 or more, the object sinks (at exactly 1 it hangs suspended).
Density examples
Example 1: A 540 g block with a volume of 200 cm³
ρ = 540 ÷ 200 = 2.7 g/cm³ = 2700 kg/m³
It matches aluminum (2.7 g/cm³). Since it is above 1, it sinks in water: it is 2.7 times denser.
Example 2: Mass of 2 liters of dry oak
Dry oak is about 0.75 g/cm³ and 2 L is 2000 cm³:
m = 0.75 × 2000 = 1500 g = 1.5 kg
Example 3: Volume of 1 kg of gold
Gold is 19.3 g/cm³ and 1 kg is 1000 g:
V = 1000 ÷ 19.3 = 51.8135 cm³
That is less than a cube 4 cm on a side (64 cm³).
Example 4: How much of a piece of ice sits under the water?
0.917 ÷ 1 = 0.917, so it floats with 91.7 % submerged
Table of densities of common materials
Approximate values at about 20 °C and 1 atm. Rows marked ≈ are typical values for materials that vary (wood, cork, concrete, glass, oil and seawater). Reference sources: CRC Handbook of Chemistry and Physics, NIST and The Engineering ToolBox. Pure water is 1 g/cm³ at 4 °C and 0.998 at 20 °C.
| Material | g/cm³ | kg/m³ | lb/ft³ | In water |
|---|---|---|---|---|
| Air | 0.001204 | 1.204 | 0.07516 | Floats |
| Cork | ≈ 0.24 | ≈ 240 | ≈ 14.98 | Floats |
| Pine (dry wood) | ≈ 0.5 | ≈ 500 | ≈ 31.21 | Floats |
| Oak (dry wood) | ≈ 0.75 | ≈ 750 | ≈ 46.82 | Floats |
| Ethanol | 0.789 | 789 | 49.26 | Floats |
| Olive oil | ≈ 0.915 | ≈ 915 | ≈ 57.12 | Floats |
| Ice | 0.917 | 917 | 57.25 | Floats |
| Water | 1 | 1000 | 62.43 | Hangs suspended |
| Seawater | ≈ 1.025 | ≈ 1025 | ≈ 63.99 | Sinks |
| Concrete | ≈ 2.4 | ≈ 2400 | ≈ 149.83 | Sinks |
| Glass | ≈ 2.5 | ≈ 2500 | ≈ 156.07 | Sinks |
| Aluminum | 2.7 | 2700 | 168.56 | Sinks |
| Iron | 7.87 | 7870 | 491.31 | Sinks |
| Copper | 8.96 | 8960 | 559.35 | Sinks |
| Silver | 10.49 | 10490 | 654.87 | Sinks |
| Lead | 11.34 | 11340 | 707.93 | Sinks |
| Mercury | 13.53 | 13530 | 844.65 | Sinks |
| Gold | 19.3 | 19300 | 1204.86 | Sinks |
Density unit equivalents
| Unit | 1 unit equals | 1 g/cm³ equals |
|---|---|---|
| g/cm³ | 1 g/cm³ | 1 g/cm³ |
| kg/m³ | 0.001 g/cm³ | 1000 kg/m³ |
| g/mL | 1 g/cm³ | 1 g/mL |
| kg/L | 1 g/cm³ | 1 kg/L |
| lb/ft³ | 0.016018 g/cm³ | 62.428 lb/ft³ |
Frequently asked questions
How do you calculate density?
Divide the mass by the volume: ρ = m ÷ V. If the mass is in grams and the volume in cm³, the density comes out in g/cm³.
How do I convert g/cm³ to kg/m³?
Multiply by 1000. For example, 2.7 g/cm³ is 2700 kg/m³. Also, g/cm³, g/mL and kg/L are all the same value.
Why do some objects float?
Because their density is lower than the liquid. A steel ship floats because its shape encloses a lot of air, and its average density, hull and air together, ends up below that of water.
Does density change with temperature?
Yes. Most things expand when heated, so the volume goes up and the density goes down. That is why table values state the temperature.
Learn more
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