Calculator Inputs
The page uses a single-column flow, while the calculator fields adapt to three columns on large screens, two on tablets, and one on mobile.
Formula Used
Specific gravity is a unitless ratio that compares a fluid’s density with water. API gravity expresses petroleum liquid density on a scale used widely in refining, storage, and transport work.
For petroleum measurements, specific gravity is normally referenced at 60°F or 15.6°C. This calculator can label other references, but it does not apply automatic temperature correction.
How to Use This Calculator
- Select the conversion mode.
- Enter either specific gravity or API gravity.
- Adjust the water density if your workflow needs a custom value.
- Choose the result precision.
- Set the graph range for specific gravity.
- Click Calculate to view the result section above the form.
- Use the export buttons to save the result as CSV or PDF.
Example Data Table
| Sample | Specific Gravity | API Gravity | Density (kg/m³) | Category |
|---|---|---|---|---|
| Condensate | 0.7200 | 65.0278 | 719.2915 | Light petroleum |
| Naphtha | 0.7500 | 57.1667 | 749.2620 | Light petroleum |
| Jet fuel | 0.8000 | 45.3750 | 799.2128 | Light petroleum |
| Diesel range | 0.8500 | 34.9706 | 849.1636 | Light petroleum |
| Lubricating oil | 0.9000 | 25.7222 | 899.1144 | Medium petroleum |
| Water reference | 1.0000 | 10.0000 | 999.0160 | Extra heavy petroleum |
Frequently Asked Questions
1. What does API gravity tell me?
API gravity indicates how heavy or light a petroleum liquid is compared with water. Higher API values mean lighter liquids, while lower values indicate heavier liquids.
2. Why does specific gravity have no unit?
Specific gravity is a ratio of one density divided by another density. Because the units cancel out, the final value is dimensionless.
3. Why is 60°F or 15.6°C important?
That reference temperature is standard in petroleum measurements. It helps ensure that readings from different tanks, labs, and reports remain comparable.
4. Can I use this calculator for non-petroleum liquids?
You can mathematically convert the values, but API gravity is mainly intended for petroleum liquids. Interpretation outside that context may be less meaningful.
5. What happens if I change the water density input?
Changing water density only affects the estimated fluid density output. The API and specific gravity conversion equations remain the same.
6. Does this calculator apply temperature correction automatically?
No. It labels the reference condition you selected, but it does not correct measured density or specific gravity to a new temperature basis.
7. Why is water equal to 10 API?
When specific gravity equals 1.0, the formula returns 10 API. Liquids above 10 API are lighter than water, while those below 10 API are heavier.
8. Can I export my result for reports?
Yes. After calculation, use the CSV button for spreadsheet-friendly output or the PDF button for a portable report snapshot.