Drive-Thru Throughput Calculator

Why Drive-Thru Speed Matters

The drive-thru is the revenue engine for most QSR concepts, accounting for 65-75% of total sales at burger chains and up to 85% at coffee drive-thrus. Every second of service time directly impacts how many cars you can serve per hour and, by extension, your daily and annual revenue ceiling.

The math is straightforward: a single-lane drive-thru operating at 280 seconds per car can theoretically serve 12.9 cars per hour. Reducing that to 250 seconds lifts capacity to 14.4 cars per hour, a 12% increase that compounds across every operating hour, every day, all year.

Throughput vs. Speed of Service

Speed of service (how fast you complete each order) and throughput (total cars served) are related but not identical. You can have fast service times but poor throughput if there are gaps between cars, slow payment processing, or order accuracy issues that require corrections at the window.

The efficiency slider in the calculator accounts for this gap. Most well-run operations achieve 80-90% efficiency, meaning the actual cars served per hour fall 10-20% below the theoretical maximum. Outdoor order-takers, dual ordering points, and AI voice ordering systems all target this efficiency gap rather than raw service speed.

Multi-Lane Economics

Adding a second lane does not double throughput. Real-world data shows a 60-80% capacity increase rather than 100%, due to merge-point bottlenecks at the payment and pickup windows. The construction cost for a second lane typically runs $200,000-$400,000 depending on site configuration. Use the scenarios above to model whether the incremental revenue justifies the capital expenditure for your specific volume and ticket size.