Bunker Density vs Temperature

Correct fuel density from the delivery temperature to 15 °C using the ISO 91-1 linear formula. Converts a litre-based bunker volume into the contractual mass.

VoyageBunkersISO 91-1

Loading calculator…

This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

\rho_T = \rho_{15} - \alpha (T - 15)

Symbol	Meaning	Unit
$\rho_T$	Density at delivery temperature	kg / m³
$\rho_{15}$	Certified density at 15 °C	kg / m³
$T$	Observed bunker temperature	°C
$\alpha$	Volumetric expansion coefficient - 0.64 (residual) / 0.70 (distillate)	kg / m³ / °C
$V_\text{obs}$	Observed bunker volume	m³
$m$	Delivered mass	t
$10^{-3}$	Kilograms → tonnes

Source: ISO 91-1 - *Petroleum measurement tables*; ISO 8217 - *Marine fuels specification*

In short

Correct marine fuel density from observed temperature to 15 °C per ISO 91-1 and convert bunker volume to mass.

Learn the theory Bunker Quality and ISO 8217 Marine Fuel Standards