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Density,
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24+ unitsStep-by-stepMaterial lookupBuoyancy check
D = M / VM = D × VV = M / D
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DensityLeave empty to solve
MassLeave empty to solve
VolumeLeave empty to solve

Material
Quick Reference

Click any material to pre-fill the density field in the calculator above.

Reference

Density reference: tables & conversions.

The calculator above solves D = M / V and its two rearrangements with unit-aware arithmetic across 24 units. The reference below collects the lookup values that calculation depends on: densities of common solids, liquids at 20 °C, and gases at standard temperature and pressure, the conversion factors between metric and customary units, and the specific gravity scale that determines whether a sample floats in fresh water.

Densities of common solids at 20 °C, 1 atm

Values from the CRC Handbook of Chemistry and Physics, 102nd edition, with wood ranges drawn from the USDA Wood Handbook (FPL-GTR-190). Click any material card above to pre-fill the calculator with that density.

Materialg/cm³kg/m³lb/ft³
Aluminum2.7002700168.6
Brass (70/30)8.5008500530.6
Concrete (typical)2.4002400149.8
Copper8.9608960559.4
Cork0.22022013.7
Glass (soda lime)2.5202520157.3
Gold19.320193201206.1
Ice (0 °C)0.91791757.2
Iron (pure)7.8747874491.5
Lead11.34011340707.9
Magnesium1.7381738108.5
Mercury (liquid)13.53413534844.9
Nickel8.9088908556.1
Oak (white, kiln dried)0.7575046.8
Pine (eastern white)0.35 to 0.50350 to 50021.8 to 31.2
Platinum21.450214501339.0
Silver10.49010490654.9
Steel (mild carbon)7.8507850490.1
Tin7.2657265453.5
Titanium4.5064506281.3
Tungsten19.250192501201.7
Zinc7.1407140445.7

Common liquids at 20 °C

Pure water reaches its peak density of 1000 kg/m³ at 3.98 °C, then loses about 0.02% per degree as it warms. The 20 °C row below is the standard laboratory reference.

Liquidg/cm³kg/m³SG (vs water at 4 °C)
Acetone0.7847840.784
Diesel fuel0.8328320.832
Ethanol0.7897890.789
Gasoline (auto)0.7457450.745
Glycerin1.26012601.260
Honey (typical)1.42014201.420
Mercury13.5341353413.534
Methanol0.7927920.792
Milk (whole)1.03010301.030
Olive oil0.9189180.918
Saltwater (ocean)1.02510251.025
Water (pure, 20 °C)0.9989980.998
Water (pure, 4 °C)1.00010001.000

Common gases at STP (0 °C, 1 atm)

Gas density tracks the ideal gas law: ρ = (P·M) / (R·T), where M is molar mass in kg/mol and R is 8.31446 J/(mol·K). Doubling pressure doubles density; doubling absolute temperature halves it.

GasMolar mass (g/mol)kg/m³g/L
Hydrogen (H₂)2.0160.08990.0899
Helium (He)4.0030.17860.1786
Methane (CH₄)16.040.71680.7168
Ammonia (NH₃)17.030.77100.7710
Neon (Ne)20.180.90020.9002
Nitrogen (N₂)28.021.25061.2506
Air (dry, sea level)28.961.29221.2922
Oxygen (O₂)32.001.42901.4290
Argon (Ar)39.951.78381.7838
Carbon dioxide (CO₂)44.011.97701.9770
Sulfur hexafluoride (SF₆)146.066.51806.5180

Density unit conversion factors

To convert a value in the left column into the right column, multiply by the factor shown. The calculator above performs these conversions internally; the table is for hand checks and crossing between drawings or spec sheets.

FromToMultiply by
g/cm³kg/m³1000
g/cm³kg/L1.000
g/cm³lb/ft³62.428
g/cm³lb/gal (US)8.3454
g/cm³lb/in³0.036127
g/cm³oz/in³0.578037
kg/m³g/cm³0.001
kg/m³lb/ft³0.062428
kg/m³slug/ft³0.001940
lb/ft³g/cm³0.016018
lb/ft³kg/m³16.018
lb/gal (US)lb/gal (UK)1.20095
lb/in³g/cm³27.6799

Mass unit conversion factors

FromToMultiply by
kgg1000
kgmg1,000,000
kglb2.20462
kgoz35.2740
ggrain15.4324
lbg453.592
lbkg0.453592
lboz16
ozg28.3495
metric ton (t)kg1000
metric ton (t)short ton (US)1.10231
short ton (US)kg907.185
long ton (UK)kg1016.05
stone (UK)kg6.35029
caratg0.200

Volume unit conversion factors

A US fluid ounce is 29.5735 mL and a UK fluid ounce is 28.4131 mL. They share a name and a symbol but resolve to different volumes; the calculator above keeps the two as separate units to prevent silent miscalculations.

FromToMultiply by
L1000
ft³35.3147
gal (US)264.172
yd³1.30795
LmL1000
Lcm³1000
Lgal (US)0.264172
Lgal (UK)0.219969
Lfl oz (US)33.8140
Lfl oz (UK)35.1951
ft³in³1728
ft³gal (US)7.48052
in³mL16.3871
gal (US)L3.78541
gal (UK)L4.54609

Specific gravity scale and buoyancy threshold

Specific gravity (SG) divides a substance's density by the density of pure water at 4 °C (1000 kg/m³). The result is dimensionless, which is why pycnometer measurements and hydrometer readings are usually quoted as SG rather than absolute density. The float-or-sink threshold sits at SG = 1.000. Anything below floats in fresh water; anything above sinks.

SubstanceSGBuoyancy in fresh water
Hydrogen (gas)0.000069rises
Air (gas)0.001225rises
Balsa wood0.16floats
Cork0.22floats
Pine (eastern white)0.35 to 0.50floats
Gasoline0.745floats
Ice0.917floats
Pure water (20 °C)0.998neutral
Pure water (4 °C)1.000neutral
Seawater1.025sinks
Aluminum2.700sinks
Iron7.874sinks
Lead11.340sinks
Gold19.320sinks

Density formula and worked example

The three forms of the relation:

D = M / V (solve for density) M = D × V (solve for mass) V = M / D (solve for volume)

Worked example. A graduated cylinder reads 250 mL of olive oil. The combined cylinder and oil mass on a balance is 480.5 g; the empty cylinder is 251.0 g.

M_oil = 480.5 - 251.0 = 229.5 g V_oil = 250 mL = 250 cm³ D_oil = 229.5 / 250 = 0.918 g/cm³

Convert to SI: 0.918 g/cm³ × 1000 = 918 kg/m³. Convert to imperial: 0.918 × 62.428 = 57.3 lb/ft³. Compare to the liquid table above: olive oil reference is 0.918 g/cm³, agreement to three decimal places. The buoyancy indicator compares 918 kg/m³ against 1000 kg/m³ and returns “floats in water” because the sample is less dense than the reference fluid.

Standards and primary sources

ReferenceUsed for
CRC Handbook of Chemistry and Physics, 102nd ed.Solid and liquid densities at 20 °C
NIST WebBook (webbook.nist.gov)Gas densities and molar masses
USDA Forest Products Lab, Wood Handbook (FPL-GTR-190)Wood density ranges by species
ASTM D1505 / D792Plastic and polymer density test methods
ASTM D5057Petroleum liquid density and SG
BIPM SI Brochure, 9th ed.Definition of kg, m, mol after 2019 redefinition
ISO 80000-4:2019Quantities and units for mechanics
Avogadro constant6.02214076 × 10²³ mol⁻¹ (exact)
Planck constant6.62607015 × 10⁻³⁴ J·s (exact)

Related concepts

  • Archimedes principle:Buoyant force equals weight of fluid displaced; underlies the float/sink behavior the indicator reports.
  • Pycnometer measurement:A calibrated flask used to determine the density of liquids and finely divided solids by displacement.
  • Thermal expansion coefficient:Liquids and solids change density with temperature; for water near 4 °C the coefficient is anomalously near zero, then turns positive.
  • Ideal gas law:PV = nRT relates the four state variables for gases; combined with molar mass it gives the density values in the gas table above.
  • Molar volume:At STP, one mole of any ideal gas occupies 22.414 L, which converts cleanly between mass and volume for gas-phase calculations.
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