Density Converter (kg/m³, g/cm³, lb/ft³, API)
Type in either box to turn kg/m³ into lb/ft³, g/cm³ into lb/gal, API gravity into kg/m³ or any pair of density units, with the answer in every unit at once.
Type in either box. Tap a unit under a box to change it.
The buttons fill in typical densities (they vary with temperature and grade). For an exact figure use the label, data sheet or delivery note. To work out a density from your own mass and volume, use the density calculator.
kg/m³ to lb/ft³ table
Common values both ways. Change the units above and the table follows.
| kg/m³ | lb/ft³ |
|---|---|
| 0.1 | 0.006242796 |
| 0.5 | 0.03121398 |
| 1 | 0.06242796 |
| 2 | 0.1248559 |
| 5 | 0.3121398 |
| 10 | 0.6242796 |
| 20 | 1.248559 |
| 50 | 3.121398 |
| 100 | 6.242796 |
| 250 | 15.60699 |
| 500 | 31.21398 |
| 750 | 46.82097 |
| 1,000 | 62.42796 |
| 1,500 | 93.64194 |
| 2,000 | 124.8559 |
| 2,500 | 156.0699 |
| 5,000 | 312.1398 |
| 10,000 | 624.2796 |
| lb/ft³ | kg/m³ |
|---|---|
| 0.1 | 1.601846 |
| 0.5 | 8.009232 |
| 1 | 16.01846 |
| 2 | 32.03693 |
| 5 | 80.09232 |
| 10 | 160.1846 |
| 20 | 320.3693 |
| 50 | 800.9232 |
| 100 | 1,601.846 |
| 250 | 4,004.616 |
| 500 | 8,009.232 |
| 750 | 12,013.85 |
| 1,000 | 16,018.46 |
| 1,500 | 24,027.7 |
| 2,000 | 32,036.93 |
| 2,500 | 40,046.16 |
| 5,000 | 80,092.32 |
| 10,000 | 160,184.6 |
Typical densities (typical, varies with temperature)
| Material | kg/m³ | g/cm³ | lb/ft³ | lb/US gal |
|---|---|---|---|---|
| Water (4 °C) | 1,000 | 1 | 62.43 | 8.345 |
| Sea water | 1,025 | 1.025 | 63.99 | 8.554 |
| Ice | 917 | 0.917 | 57.25 | 7.653 |
| Petrol / gasoline | 740 | 0.74 | 46.2 | 6.176 |
| Diesel | 840 | 0.84 | 52.44 | 7.01 |
| Jet A-1 (15 °C) | 800 | 0.8 | 49.94 | 6.676 |
| Milk | 1,030 | 1.03 | 64.3 | 8.596 |
| Olive oil | 910 | 0.91 | 56.81 | 7.594 |
| Honey | 1,420 | 1.42 | 88.65 | 11.85 |
| Air (sea level, 15 °C) | 1.225 | 0.001225 | 0.07647 | 0.01022 |
| Wood (pine) | 500 | 0.5 | 31.21 | 4.173 |
| Wood (oak) | 750 | 0.75 | 46.82 | 6.259 |
| Concrete | 2,400 | 2.4 | 149.8 | 20.03 |
| Aluminium | 2,700 | 2.7 | 168.6 | 22.53 |
| Steel | 7,850 | 7.85 | 490.1 | 65.51 |
| Gold | 19,300 | 19.3 | 1,205 | 161.1 |
Typical figures to give a feel for the numbers (g/cm³ is kg/m³ ÷ 1,000, the same number as specific gravity), the same ones the density calculator uses; Jet A-1 is the 0.800 kg/L figure from the jet fuel converter. Liquids get lighter as they warm up, fuels vary by grade and season, and wood and concrete by moisture and mix. Water is 1,000 kg/m³ at about 4 °C and 998 kg/m³ at 20 °C.
How your density is converted
Every unit goes into kilograms per cubic metre first, then out to the unit you want.
- 1
Your density
1,000 kg/m³ →
lb/ft³ - 2
Into kg per cubic metre
Already in kg per cubic metre:
1,000 kg/m³ - 3
Out to lb/ft³
1,000 ÷ 16.01846 =
62.42796 lb/ft³ - 4
The shortcut
1 kg/m³ =
0.06242796 lb/ft³
Read more: the formula, worked examples, API gravity, mass ↔ volume and a table of typical densities
The formula
kg per m³ = your number × kg/m³ in one of your unit
answer = kg per m³ ÷ kg/m³ in one of the unit you want
kg/m³ → lb/ft³: lb/ft³ = kg/m³ ÷ 16.0184634
g/cm³ → kg/m³: kg/m³ = g/cm³ × 1,000
specific gravity = kg/m³ ÷ 1,000
SG at 60 °F = 141.5 ÷ (°API + 131.5)
°API = 141.5 ÷ SG − 131.5
mass = volume × density
volume = mass ÷ density
Worked example
1,000 kg/m³ in lb/ft³. One lb/ft³ is 0.45359237 kg ÷ (0.3048 m)³ = 0.45359237 ÷ 0.028316846592 = 16.0184634 kg/m³, so 1,000 ÷ 16.0184634 = 62.42796 lb/ft³. As a shortcut, 1 kg/m³ = 0.06242796 lb/ft³.
Other everyday pairs: 1 g/cm³ × 1,000 = 1,000 kg/m³. 1,000 kg/m³ ÷ 119.826427 (kg/m³ in 1 lb/US gal) = 8.345404 lb/US gal, and ÷ 99.776373 = 10.02241 lb/UK gal. 1 slug/ft³ = 14.5939029 kg ÷ 0.028316846592 m³ = 515.3788 kg/m³ = 32.17405 lb/ft³.
API gravity (oils)
API gravity is a scale, not a plain multiple, so there is no single factor. With 30 °API: SG at 60 °F = 141.5 ÷ (30 + 131.5) = 141.5 ÷ 161.5 = 0.876161. Times water at 60 °F (999.016 kg/m³) = 875.2988 kg/m³, or 7.304723 lb/US gal. The other way, diesel-like oil at 850 kg/m³ has SG 850 ÷ 999.016 = 0.850837, so °API = 141.5 ÷ 0.850837 − 131.5 = 34.80678 °API. Water is exactly 10 °API. The Baumé scales work the same way: heavier than water °Bé = 145 − 145 ÷ SG, lighter than water °Bé = 140 ÷ SG − 130.
Mass ↔ volume (Advanced)
With the defaults (840 kg/m³, a typical diesel): 50 L is 0.05 m³, so its mass is 0.05 × 840 = 42 kg (42 ÷ 0.45359237 = 92.59415 lb). And 1,000 kg takes up 1,000 ÷ 840 = 1.190476 m³ = 1,190.476 L (314.4905 US gal, 261.8682 UK gal).
Unit names
| Unit | Also written | In kg/m³ |
|---|---|---|
| g/cm³ | g/cc, g/mL, kg/L, t/m³ | 1,000 |
| g/L | mg/mL, kg/m³ | 1 |
| lb/ft³ | pcf, lb/cu ft | 16.01846 |
| lb/in³ | pci, lb/cu in | 27,679.9 |
| lb/US gal | ppg (mud weight) | 119.8264 |
| slug/ft³ | slug/cu ft | 515.3788 |
| gr/US gal | gpg (water hardness) | 0.01711806 |
| SG | relative density, SG | 1,000 |
Factors are exact by definition: 1 lb = 0.45359237 kg, 1 oz = 1/16 lb, 1 grain = 1/7,000 lb, 1 ft = 0.3048 m, 1 in = 0.0254 m, 1 yd = 0.9144 m, 1 US gallon = 231 in³ = 3.785411784 L, 1 UK gallon = 4.54609 L, 1 slug = 1 lbf·s²/ft = 14.5939029 kg. Specific gravity here uses water at 4 °C as 1,000 kg/m³; API gravity and Baumé use SG at 60 °F against water at 60 °F, taken as 999.016 kg/m³. Checked 17 October 2026 against NIST Special Publication 811.
Common questions
How do I convert kg/m³ to g/cm³?
Divide by 1,000. So 7,850 kg/m³ (steel) is 7.85 g/cm³. Going the other way, multiply g/cm³ by 1,000. g/cm³, g/mL and kg/L are all the same number.
How do I convert kg/m³ to lb/ft³?
Divide by 16.0185, or multiply by 0.062428. So water at 1,000 kg/m³ is 62.43 lb/ft³. One lb/ft³ is exactly 0.45359237 kg ÷ 0.028316846592 m³ = 16.0184634 kg/m³.
How many pounds does a gallon of water weigh?
About 8.345 lb per US gallon and 10.02 lb per UK (imperial) gallon, taking water as 1,000 kg/m³. Warm water is a little lighter: at 20 °C it is about 998 kg/m³, or 8.33 lb per US gallon.
What is specific gravity?
Specific gravity (SG) is how many times denser something is than water. Here SG = density ÷ 1,000 kg/m³ (water at about 4 °C), so it is the same number as g/cm³. Diesel at 840 kg/m³ has an SG of 0.84, and floats on water.
How do I convert API gravity to density?
First get specific gravity at 60 °F: SG = 141.5 ÷ (°API + 131.5). Then multiply by the density of water at 60 °F, 999.016 kg/m³. So 30 °API is SG 0.87616, which is 875.30 kg/m³. Water is 10 °API; a higher number means a lighter oil.
How do I find mass from volume and density?
Mass = volume × density, with the units matched. 50 litres of diesel at 840 kg/m³ is 0.05 m³ × 840 = 42 kg (92.59 lb). For volume, divide instead: 1,000 kg of diesel is 1,000 ÷ 840 = 1.1905 m³ (1,190.5 L). Advanced has a helper that mixes any units.
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