The stoichiometric air-to-fuel ratio for heavy fuel oil is 14.4:1, which is essential for calculating the enthalpy of gas from heavy fuel oil combustion. A user provided a link to a free MS Excel file that assists with combustion calculations for coal and oil. This resource can be helpful for those needing to perform similar calculations. The discussion centers on the importance of accurate ratios for combustion efficiency. Accessing the provided file may enhance understanding and application of these concepts.