The total cost of driving from Colorado to California (one-way) is $119.87 at current gas prices. The round trip cost would be $239.74 to go from Colorado to California and back to Colorado again. Regular fuel costs are around $2.63 per gallon for your trip. This calculation assumes that your vehicle gets an average gas mileage of 25 mpg for a mix of city and highway driving. All currency units are U.S. Dollars.