Gear Ratio Calculator RPM

Gear Ratio Calculator RPM is an offline drivetrain calculator for cars, motorcycles, RC builds, karting and 4x4 projects. It helps you plan tire, gear ratio, final drive and RPM changes before you buy parts or test a setup. Built for real projects Create a project for each vehicle or build. Save a baseline setup, duplicate it, then compare changes such as a new tire size, a different final drive, sprocket changes or alternate gear ratios. Calculation records are stored locally so you can return to previous results later. What you can calculate - Speed at a given RPM for each gear - Engine RPM at a target road speed - Theoretical redline speed by gear - Tire diameter, circumference and speedometer error - Final drive changes and cruising RPM - Shift RPM drop and gear spread - Motorcycle sprocket combinations - Setup comparisons with tables and charts Designed for offline use No account, no ads, no subscriptions and no server are required. Your projects and records stay on your device. You can export results as PDF, CSV or images using the iOS share sheet. Useful in the garage, at the shop or while planning a build Use it to compare stock and modified setups, check highway cruising RPM, plan a track setup, estimate the effect of tire changes or prepare a report for a customer. Important note The results are theoretical estimates. Real-world performance can be affected by engine power, aerodynamic drag, tire deformation, slip, drivetrain loss, vehicle weight, road conditions and mechanical condition. This app is for planning and comparison only. Always follow local traffic laws and use the results safely.