API Gravity Calculator

Convert specific gravity to API gravity for petroleum.

API gravity (°API) 34.971

Formula: API = 141.5 ÷ SG − 131.5

Step-by-step with your numbers:

1. Values used:

2. Specific gravity (60°F) = 0.85

4. API gravity = 34.971°API

Did we solve your problem today?

API gravity rates how heavy or light a petroleum liquid is compared to water.

The math behind it

API = 141.5 ÷ SG − 131.5. Above 10 °API floats on water; below 10 sinks.

SG 0.85 → about 34.97 °API.

What is 'light' crude?

Higher API (lower density) oils are called light; they generally fetch more.