API to Density Calculator

Convert API Gravity to density and specific gravity instantly. Designed for petroleum engineers, refinery operators, and oil industry professionals.

PetroConvert Studio:

Professional petroleum property calculator with multi-unit support and fluid presets for accurate density conversions.

Petroleum Converter

Mode
°API

Range: -50 to 150 (higher = lighter liquid)

🏭
Heavy
15°API
🛢️
Crude
30°API
🚗
Diesel
35°API
✈️
Kerosene
40°API
Gasoline
60°API

Click to set typical API value

Industry standard is 60°F (15.6°C)

Conversion Results

150 100 50 0
Heavy
Light

Enter API gravity value

then click "Calculate" for results

API to Density Calculator

Petroleum liquids are classified by API gravity, but engineering work needs actual density values. This gap between industry terminology and physical measurements creates friction in daily calculations. An API to density calculator bridges that gap quickly.

The Conversion Formula

API to Specific Gravity
Specific Gravity = 141.5 ÷ (API + 131.5)
Example: API 35 → SG = 141.5 ÷ 166.5 = 0.850
Specific Gravity to Density
Density (kg/m³) = Specific Gravity × 999.016
Water density at 60°F = 999.016 kg/m³
Reverse: Density to API
API = (141.5 ÷ Specific Gravity) − 131.5

Example Conversions

API Gravity Specific Gravity Density (kg/m³) Classification
10 1.000 999 Extra Heavy
20 0.934 933 Heavy
30 0.876 875 Medium
40 0.825 824 Light
50 0.780 779 Light
60 0.739 738 Very Light

Understanding API Gravity

API gravity measures how light or heavy a petroleum liquid is compared to water. The scale seems backwards at first — higher API means lighter oil. Water sits at API 10, anything below is heavier than water and sinks.

Crude oils range from about 10 to 50 API. Light crudes (30-40 API) flow easily and yield more gasoline. Heavy crudes (10-20 API) need more processing but often cost less per barrel.

Why Accurate Conversion Matters

Density affects storage tank capacity, pipeline flow rates, shipping weight limits, and refinery processing. A small error in density can mean thousands of dollars difference in transportation costs or product yield.

Industry Note:

Standard API gravity is measured at 60°F (15.6°C). Temperature corrections may be needed for field measurements taken at different temperatures.