Why do gas stations always round up to whole numbers?

[CarlosLynn]

The reason gas stations often round up to whole numbers is for the convenience of cashiering, as cash payments were predominant in the past. To facilitate transactions, gas station attendants would proactively round up the amount. At high-traffic stations or during specific periods like long holidays, rounding up plays a very significant role. However, if consumers choose fixed-amount refueling or payment methods like fuel cards, attendants will not perform rounding. In less developed regions of central and western China, where mobile payment penetration is not high, paper currency is still commonly used. For large refined oil enterprises like PetroChina, fuel dispensers and settlement systems are standardized nationwide, so any changes must consider regional differences.