Calculate heating oil usage per day, month and year from tank readings, estimate days until your tank hits reserve, or find oil needed for a heat demand.

Read both volumes from the same gauge. Blank deliveries or reserve mean zero.

Deliveries, reserve, cost and floor area

Blank omits cost. Delivery fees are excluded.

Heating Oil Usage Formula

HOU = TU / HS

Variables:

  • HOU is the Heating Oil Usage (gallons/ft^2)
  • TU is the total usage (gallons)
  • HS is the home size (ft^2)

To calculate Heating Oil Usage, divide the total usage in gallons by the home size.

How to Calculate Heating Oil Usage?

For the formula below, select Oil use per floor area. The other modes estimate measured daily use, time until reserve, or oil required from useful heat demand.

  1. First, determine the total usage (gallons). 
  2. Next, determine the home size (ft^2). 
  3. Next, gather the formula from above = HOU = TU / HS.
  4. Finally, calculate the Heating Oil Usage.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

total usage (gallons) = 200

heated floor area (ft^2) = 5000; HOU = 200 / 5000 = 0.04 US gal/ft² for the same period

Measured use equals starting oil plus deliveries minus ending oil. Divide by elapsed days for average daily use. Reserve estimates assume that burn rate continues; 30- and 365-day equivalents are not seasonal forecasts. Tank percentages must be calibrated volume percentages, not raw height readings.

For useful heat demand, oil volume equals heat demand divided by efficiency and fuel energy per unit volume. Match the gross/net basis of efficiency and fuel energy. The kerosene preset uses SEAI’s July 2026 gross value of 10.18 kWh/L. The heating-oil preset retains EIA’s illustrative 138,500 Btu/US gal; supplier values may differ. Both may be replaced with a custom energy value. Optional cost is a USD fuel-only estimate; no entered price means no cost result.

FAQs

What factors can affect heating oil usage in a home?

Several factors can affect heating oil usage, including the insulation quality of the home, the efficiency of the heating system, outdoor temperatures, and the thermostat settings. Homes with poor insulation or inefficient heating systems may use more heating oil.

How can I reduce my heating oil usage?

To reduce heating oil usage, consider improving home insulation, sealing leaks around doors and windows, using programmable thermostats, maintaining your heating system regularly, and considering upgrading to a more efficient heating system.

Is heating oil usage calculated differently for different home sizes?

While the basic formula for calculating heating oil usage (gallons/ft^2) remains the same, larger homes may require more heating oil due to the greater area to be heated. However, factors like insulation and heating system efficiency play a significant role in the actual usage.