If a coworker lives near you and drives you to work every day, you may not be legally required to pay for gas, but offering to contribute is generally considered fair. You are benefiting from their fuel, car, time, and effort, especially if they make a detour to pick you up. A regular ride should feel like a shared arrangement rather than a one-sided favor.
The amount does not need to be complicated. If your coworker already takes the same route, you could offer a reasonable weekly or monthly contribution toward fuel. If they leave earlier or make a significant detour just to pick you up, contributing a little more would make sense. There is no need to calculate every mile or split every expense.
Gas is also not the only cost of driving. The driver pays for maintenance, tires, repairs, depreciation, and other vehicle expenses. You do not necessarily need to cover half of these costs, but recognizing them makes your contribution more thoughtful.
The easiest approach is to be direct and polite: **“I really appreciate you driving me to work every day. I’d like to contribute something for gas—how much do you think is fair?”** This opens the conversation without making things awkward.
If they refuse money, you can still show appreciation by occasionally buying them coffee or lunch, or giving them a gas-station gift card. **The important thing is to offer rather than assume the rides should be free.**