Specific Gravity Converter

Convert between specific gravity and various density units including kg/m³, g/cm³, lb/ft³, oz/in³, and API gravity. Essential for fluid mechanics, petroleum industry, and material science applications.

Base Formula: Density = SG × 1000 kg/m³ | API Gravity: °API = (141.5 / SG) - 131.5 | Reference: SG = 1 means same density as water at 4°C

About This Specific Gravity Converter

Our Specific Gravity Converter provides precise conversions between specific gravity and various density units used in engineering, petroleum industry, and material science. Specific gravity is a dimensionless ratio comparing the density of a substance to the density of water at 4°C (1000 kg/m³).

The converter handles all common density units and includes API gravity calculations essential for petroleum applications. Since specific gravity is unitless, a value of 1.0 means the substance has the same density as water, while values greater than 1.0 indicate denser materials and values less than 1.0 indicate lighter materials.

Key Features

Comprehensive Units

Convert between 7 essential units including specific gravity, multiple density units, and API gravity for petroleum applications.

Industry Standard

Based on water at 4°C reference standard with accurate API gravity calculations for petroleum industry use.

High Precision

Handles decimal values with precision suitable for scientific and engineering applications.

Multi-Industry Tool

Perfect for fluid mechanics, petroleum engineering, material science, and quality control applications.

Why Choose Our Converter?

  • Scientific Accuracy: Based on standard water density at 4°C (1000 kg/m³) reference
  • Petroleum Industry: Includes accurate API gravity calculations following industry standards
  • Multiple Systems: Supports both metric and imperial density units
  • Professional Grade: Suitable for laboratory, field, and industrial applications
  • Easy Understanding: Clear explanation of dimensionless nature of specific gravity
  • Instant Results: Real-time conversion with proper decimal precision
  • Mobile Friendly: Responsive design perfect for field work and laboratory use

Frequently Asked Questions

What is specific gravity and why is it important?

Specific gravity is a dimensionless ratio comparing a substance's density to water's density at 4°C (1000 kg/m³). It's important because it provides a universal way to compare material densities regardless of the unit system used, making it essential for quality control and material identification.

How do I interpret specific gravity values?

SG = 1.0 means same density as water; SG > 1.0 means denser than water (sinks); SG < 1.0 means lighter than water (floats). For example, aluminum has SG ≈ 2.7, while gasoline has SG ≈ 0.74.

What is API gravity and when is it used?

API gravity is a petroleum industry standard where °API = (141.5/SG) - 131.5. Higher API values indicate lighter crude oils. Light crude: >31.1°API; Medium crude: 22.3-31.1°API; Heavy crude: 10-22.3°API; Extra heavy: <10°API.

Why is water at 4°C used as the reference?

Water reaches its maximum density at 4°C (1000 kg/m³ exactly), making it the most stable reference point. This temperature is used internationally for specific gravity measurements to ensure consistency across different applications and locations.

Can I use this converter for gases?

This converter is designed primarily for liquids and solids. For gases, specific gravity is typically referenced to air rather than water, and density varies significantly with temperature and pressure, requiring different calculation methods.

What are typical specific gravity ranges for common materials?

Gasoline: 0.68-0.74; Diesel: 0.82-0.90; Water: 1.00; Seawater: 1.025; Concrete: 2.4; Aluminum: 2.7; Steel: 7.8; Lead: 11.3; Mercury: 13.6. These values help identify materials and calculate buoyancy.