Calculating the gas cost of a trip is a smart trick to budget travel expenses.

The general rule is that about two-thirds of your cost of gas at the pump is determined by crude oil cost. The rest is a combination of taxes, refining, distribution and marketing.

**Formula to calculate gas cost.**

**Example:**

If your mpg is 20 and your planning to travel for 800 miles, calculate your gas cost if the current price of gas per gallon is $ 2.

Therefore, the gas cost is $ 80.