Specific Gravity Calculator
The Specific Gravity Calculator divides a material's density by the density of water to give specific gravity (SG), a unitless number.
Interactive Specific Gravity Calculator Engine
Result = Value × Factor
How Specific Gravity Calculator Works?
The Specific Gravity Calculator works in 3 steps.
- 1
Enter or measure the density of the material in kg/L.
- 2
Divide by the reference density of water: 1.000 kg/L at 4 °C (39.2 °F) or 0.999 kg/L at 15.6 °C (60 °F).
- 3
Read the SG and the floats-or-sinks result in the comparison table.
Specific Gravity Calculator Formula
The Specific Gravity Calculator formula is:
Specific gravity (SG) = Density of material (kg/L) ÷ Density of water (kg/L)API gravity for petroleum = 141.5 ÷ SG at 60 °F − 131.5.
Worked example
Glycerin at 1.26 kg/L ÷ 1.000 kg/L = SG 1.26, so glycerin is 26% heavier than water.
An SG of 0.832 for diesel gives an API gravity of 38.6°. Petroleum buyers price crude and fuels on that API scale.
Specific Gravity Calculator Conversion Table
The Specific Gravity Calculator table gives the specific gravity (SG) of 12 materials against water at 4 °C (1.000 kg/L) and states how much lighter or heavier each material is than water.
| Material | Density (kg/L) | Specific gravity | Compared with water |
|---|---|---|---|
| Petrol / Gasoline | 0.745 | 0.745 | 25.5% lighter (floats) |
| Ethanol | 0.789 | 0.789 | 21.1% lighter (floats) |
| Diesel | 0.832 | 0.832 | 16.8% lighter (floats) |
| Olive Oil | 0.918 | 0.918 | 8.2% lighter (floats) |
| Ice | 0.917 | 0.917 | 8.3% lighter (floats) |
| Milk | 1.032 | 1.032 | 3.2% heavier (sinks) |
| Seawater | 1.025 | 1.025 | 2.5% heavier (sinks) |
| Glycerin | 1.26 | 1.26 | 26% heavier (sinks) |
| Honey | 1.42 | 1.42 | 42% heavier (sinks) |
| Sand | 1.6 | 1.6 | 60% heavier (sinks) |
| Concrete | 2.3 | 2.3 | 130% heavier (sinks) |
| Steel | 7.85 | 7.85 | 685% heavier (sinks) |
What is Specific Gravity Calculator?
The Specific Gravity Calculator is a tool that compares a material's density with a reference density and reports the ratio as specific gravity (SG). SG answers one question: how many times heavier or lighter than water is the material?
SG values below 1.000 float on water and SG values above 1.000 sink. Olive oil (SG 0.918) floats, seawater (SG 1.025) supports more weight than fresh water, and steel (SG 7.85) sinks.
What are the uses of Specific Gravity Calculator?
There are 4 main uses of the Specific Gravity Calculator: float or sink tests, antifreeze strength, gemstone checks and petroleum grading.
Float or sink tests
Recyclers separate plastics by SG in water tanks.
Antifreeze strength
Mechanics compare coolant SG with a chart to read the glycol percentage.
Gemstone checks
Jewelers identify stones by SG measured on a hydrostatic balance.
Petroleum grading
Refiners convert SG into API gravity to classify crude oil as light or heavy.
Specific Gravity Calculator FAQ
Can specific gravity be less than 1?
Yes, any material lighter than water has an SG below 1. Petrol has an SG near 0.745 and ice has an SG of 0.917.
Does specific gravity have units?
No, specific gravity has no units: the calculation divides one density by another.
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