What is crawl ratio?
Crawl ratio describes the total gear reduction between a vehicle’s engine and its wheels when in low range and first gear, an important number for off-road vehicles that need slow, controlled, high-torque movement over rough terrain.
The formula
Crawl ratio is simply the product of every reduction stage in the drivetrain: Crawl Ratio = Transfer Case Low Range Ratio × Transmission First Gear Ratio × Axle Ratio. A higher number means more torque multiplication and slower wheel speed at a given engine RPM, generally considered better for technical rock crawling.
Many off-road enthusiasts target a crawl ratio around 40:1 to 80:1 for serious rock crawling, though the ideal number depends on tire size, vehicle weight, and driving style. This calculator is for general automotive reference and educational purposes.