🖩 Specific Gravity to Density Calculator

Convert specific gravity to density in kg/m³, g/cm³ or lb/ft³ using water as the reference, or convert a density back to specific gravity.

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Calculator Functions

Function	What it does	What it requires
Density from specific gravity	Converts a specific gravity to a density in kg/m³, g/cm³, kg/L, lb/ft³ or lb/US gallon	Requires the specific gravity, the reference density and the result unit
Specific gravity from density	Converts a density to a specific gravity	Requires the substance density and the reference density

The reference density starts as water at 4 °C, 1,000 kg/m³. The other presets are water at 20 °C (998.2 kg/m³), water at 25 °C (997.05 kg/m³), water at 60 °F (999 kg/m³) and air at 15 °C and sea level (1.225 kg/m³) for gases, and a custom reference density can be entered. Every result lists the density in kg/m³, g/cm³, lb/ft³ and lb/US gallon with the reference used. An optional setting changes the decimal places.

Specific Gravity to Density Formulas

Specific gravity, also called relative density, is the ratio of the density of a substance to the density of a reference substance, which for liquids is typically water at its maximum density at 4 °C [1].

Density from specific gravity

The specific gravity is multiplied by the reference density. With water at 4 °C, a specific gravity of 0.85 is 0.85 × 1,000 = 850 kg/m³, which is 0.85 g/cm³, 53.064 lb/ft³ and 7.094 lb/US gallon. A specific gravity of 7.85 is 7.85 g/cm³. The reference matters in the third digit: the same 0.85 is 848.47 kg/m³ against water at 20 °C and 849.15 kg/m³ against water at 60 °F. For a gas measured against air, a specific gravity of 0.6 is 0.6 × 1.225 = 0.735 kg/m³.

Specific gravity from density

The density is converted to kg/m³ and divided by the reference density. A liquid at 850 kg/m³ has a specific gravity of 850 ÷ 1,000 = 0.85, a density of 0.96 g/cm³ gives 0.96, and 62.428 lb/ft³ gives 1.

How to Convert Specific Gravity to Density

Multiply the specific gravity by the density of water in the unit wanted: 1 for g/cm³, 1,000 for kg/m³, 62.43 for lb/ft³ or 8.345 for lb/US gallon. A specific gravity of 1.2 is 1.2 g/cm³, 1,200 kg/m³, 74.91 lb/ft³ or 10.014 lb/US gallon. In g/cm³ the density has the same number as the specific gravity, because water at 4 °C is 1 g/cm³ [1].

Specific gravity	g/cm³	kg/m³	lb/ft³	lb/US gal
0.6	0.6	600	37.46	5.007
0.7	0.7	700	43.70	5.842
0.8	0.8	800	49.94	6.676
0.85	0.85	850	53.06	7.094
0.9	0.9	900	56.19	7.511
1	1	1,000	62.43	8.345
1.03	1.03	1,030	64.30	8.596
1.1	1.1	1,100	68.67	9.180
1.2	1.2	1,200	74.91	10.014
1.5	1.5	1,500	93.64	12.518
2	2	2,000	124.86	16.691
2.7	2.7	2,700	168.56	22.533
7.85	7.85	7,850	490.06	65.511
13.6	13.6	13,600	849.02	113.498

The table uses water at 4 °C, rounded to 1,000 kg/m³, as the reference.

Limits of This Estimate

• A specific gravity only converts correctly with the reference it was measured against. Water is slightly less dense when warmer, about 999.1 kg/m³ at 60 °F and 998.0 kg/m³ at 70 °F [1], so the preset should match the basis stated with the specific gravity.
• The calculator does not correct the substance itself for temperature or pressure. The density applies at the conditions where the specific gravity was measured.
• The water presets are rounded values, and the air preset is the standard sea-level figure at 15 °C and 101.325 kPa. A gas specific gravity must be on the same pressure and temperature basis. These estimates are based on the best available data and estimations.

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