What if I have weight instead of density?

Divide weight by volume to get density first, or enter relative weights measured in identical volumes.

Units cancel as long as both inputs use the same unit (g/cm³, kg/m³, etc.).

Does temperature affect SG?

Yes. Density changes with temperature. Use corrected values or measure at the reference temperature.

Can I convert SG to Brix or Plato?

Not here. Use a brewing tool to convert SG to sugar-content scales.

What reference density should I use?

Water at ~4°C is 1 g/cm³. Change the reference if comparing to another fluid or standard.

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Specific Gravity Calculator

Compare the density of a substance to water or another reference substance.

Results

Specific gravity: 1.05

How to use this calculator

Enter the density (or weight per equal volume) of your sample.
Enter the reference density (water is 1 g/cm³ at ~4°C).
See the unitless specific gravity.

Inputs explained

Substance density: Measured density of the sample in any consistent units.
Reference density: Density of the reference fluid/solid; water is commonly 1 g/cm³.

How it works

SG = sample density ÷ reference density. For liquids, reference is usually water (1 g/cm³).

Formula

SG = ρsample ÷ ρreference

When to use it

Brewing hydrometer readings to gauge sugar content (OG/FG).
Comparing mineral or chemical densities to water for QC checks.
Evaluating buoyancy or material selection in engineering contexts.

Tips & cautions

Keep units consistent for both values—units cancel in the ratio.
Temperature changes density; use temperature-compensated readings for precision.
Hydrometers are calibrated to specific temps (often 20°C/68°F); adjust readings accordingly.
No automatic temperature correction.
Assumes homogeneous samples; suspensions/emulsions can read differently.
Does not convert SG to Brix/Plato; use a brewing-specific converter for that.

Worked examples

1.05 g/cm³ wort vs water

SG = 1.05

2.7 g/cm³ aluminum vs water

SG = 2.7

Deep dive

This specific gravity calculator divides your sample density by a reference density (water by default) to give a unitless SG. Enter both densities in matching units for accurate results.

Use it for brewing hydrometer readings, lab QC, or material comparisons. Temperature and unit consistency matter—apply corrections for precise work.

FAQs

What if I have weight instead of density?: Divide weight by volume to get density first, or enter relative weights measured in identical volumes.
Do units matter?: Units cancel as long as both inputs use the same unit (g/cm³, kg/m³, etc.).
Does temperature affect SG?: Yes. Density changes with temperature. Use corrected values or measure at the reference temperature.
Can I convert SG to Brix or Plato?: Not here. Use a brewing tool to convert SG to sugar-content scales.
What reference density should I use?: Water at ~4°C is 1 g/cm³. Change the reference if comparing to another fluid or standard.

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