Calculating your specific gravity is straightforward once you know the Specific Gravity formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Specific Gravity Calculator.
What is Specific Gravity?
The Specific Gravity calculation tells you your specific gravity from a few simple inputs. The figure you are solving for here is the specific gravity.
The Specific Gravity formula
The core formula is:
Specific gravity = Substance density ÷ Reference Substance density (water)Here is what each input means:
- Substance density — a value measured in kg/m³. Example: 1,025 kg/m³.
- Reference density (water) — a value measured in kg/m³. Example: 1,000 kg/m³.
How to calculate it step by step
- Write down the substance density (for example, 1,025 kg/m³).
- Write down the reference density (water) (for example, 1,000 kg/m³).
- Apply the formula above to get your specific gravity.
- Double-check the result with the Specific Gravity Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Substance density | 1,025 kg/m³ |
| Reference density (water) | 1,000 kg/m³ |
| Specific gravity | 1.0250 |
With substance density of 1,025 kg/m³ and reference density (water) of 1,000 kg/m³, the specific gravity works out to 1.0250.
Example 2
With substance density of 2,100 kg/m³ and reference density (water) of 1,000 kg/m³, the specific gravity works out to 2.1000.
| Result | Value |
|---|---|
| Specific gravity | 2.1000 |
Example 3
With substance density of 510 kg/m³ and reference density (water) of 1,000 kg/m³, the specific gravity works out to 0.5100.
| Result | Value |
|---|---|
| Specific gravity | 0.5100 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Specific Gravity Calculator does it instantly, for free, with the formula and a worked example built in.
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