1000 cubic meters or more of natural gas. How much natural gas a restaurant uses in a month depends on its size and frequency of use, the need to heat water and cook food, and the larger it is and the more frequently it is used, the more gas it will use. Smaller restaurants use around 200 cubic meters of natural gas per month, while a 2,000 sq ft will need to use more and may require more than 1,000 cubic meters of gas per month. But this is a very rough estimate and will vary from restaurant to restaurant.