Home · Calculators · Crawl & Comparison
Crawl Ratio Calculator
The headline number every build thread quotes — first gear × low range × axle, computed from your actual transmission, not a generic chart.
Crawl ratio is the total gear reduction in first gear, low range: how many times the engine turns for one turn of the tires. It is the single number off-roaders quote to compare how slowly and controllably a rig can crawl.
Formula: crawl ratio = first-gear ratio × transfer-case low × axle ratio
What this number means
Crawl ratio tells you how much reduction stands between the engine and the ground in the slowest possible gear. Higher means slower, more controlled crawling and more torque multiplication at the tire; lower means the clutch (or converter) does the work the gears should. Factory rigs run from the mid-30s (a stock Sport on street gearing) to 84:1 (a manual Rubicon) and 94.8:1 (a manual Badlands Bronco). Built crawlers chase 100:1 and beyond.
What to change next
Three levers move it: axle ratio (the regear), transfer-case low range (a 4:1 case swap), and first gear (fixed by your transmission choice). The axle ratio is the lever almost everyone can actually pull — and it also decides your highway RPM, which is why this number is always a compromise, never a maximum.
Worked example
A Wrangler JL Rubicon with the 6-speed manual: first gear 5.13 × Rock-Trac low 4.00 × axle 4.10 = 84.1:1 — the 84.13 crawl ratio Jeep publishes. The same Jeep with the 850RE automatic: 4.71 × 4.00 × 4.10 = 77.2:1, also factory-published. Run both above — the calculator reproduces the factory numbers because it uses the factory ratios.