What is the difference between density at 15 °C and 60 °F?

They are the same liquid measured at two slightly different reference temperatures (60 °F = 15.5556 °C). The ratio between them, VCF15.5556, is product-specific and comes from API MPMS Chapter 11.1 — for example 0.99932 for a typical gasoline. This calculator computes it from the commodity group.

What is weight in air vs weight in vacuum?

Weight in vacuum is true mass; weight in air is what a scale reads after air buoyancy. API MPMS 11.5.3 relates them with the apparent density equation Da = 1.000149926 × D − 1.199407795 (kg/m³). The difference is small (~1.1 kg/m³) but matters for ton-based custody.

Density / Weight / Volume Conversion

Input

Commodity Group

Input Basis

Value

kg/m³

📚 Learn the Theory

Density bases, weight-in-air buoyancy, the VCF₁₅.₅₅₅₆ basis change, and barrel/ton conversions

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Key Relations

bbl@60/MT = (1000/D60) × 6.289811

RD15 = D15 / 999.102

RD60/60 = D60 / 999.016

°API = 141.5/RD60/60 − 131.5

Apparent = 1.000149926·D − 1.199407795

VCF₁₅.₅₅₅₆ = D60/D15 (product-specific)

Standards & References

API MPMS Ch. 11.5.3
Density/Weight/Volume Intraconversion — Conversions for Absolute Density at 15 °C
API MPMS Ch. 11.1 / ASTM D1250
VCF₁₅.₅₅₅₆ (product-specific 15 °C ↔ 60 °F factor)

Engineering Notes

Master variable is absolute density at 15 °C; all else derives from it.
VCF₁₅.₅₅₅₆ depends on the commodity (Ch. 11.1).
Tons: metric = 1000 kg, long = 1016.05 kg, short = 907.18 kg.
Weight in air ≈ true mass − ~1.1 kg/m³ buoyancy.

Frequently Asked Questions

How do you convert API gravity to barrels per metric ton?

Convert API to absolute density at 60 °F, then bbl/MT = (1000/D60) × 6.289811 (API MPMS 11.5.3).

Density at 15 °C vs 60 °F?

Same liquid, two reference temperatures (60 °F = 15.5556 °C). The ratio VCF₁₅.₅₅₅₆ is product-specific from Ch. 11.1 — e.g. 0.99932 for gasoline.

Weight in air vs vacuum?

Apparent (air) density = 1.000149926 × D − 1.199407795 kg/m³; true mass is the in-vacuum value.

Density / Weight / Volume Conversion Calculator

Input

📚 Learn the Theory

Results

Key Relations

Standards & References

Engineering Notes

Frequently Asked Questions

Density / Weight / Volume Conversion Calculator

Input

📚 Learn the Theory

Results

Key Relations

Standards & References

Engineering Notes

Frequently Asked Questions

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