I have seen a few of these across the Internet, so I did some homework and figured out the math. I also included a little shift point guide at the bottom for those of us that do acceleration runs. Use the size of your drive wheels (rear in most cases) and use decimals for gear ratios. The example numbers are the values for the 2004 my330i ZHP Project Car Enjoy! To calculate MPH at various RPMs in each gear: (All fields are required) TIRE WIDTH (in mm) Example: (255/35-18) ASPECT RATIO Example: (255/35-18) WHEEL SIZE (in inches) Example: (255/35-18) 1ST GEAR Example: 4.35 2ND GEAR Example: 2.50 3RD GEAR Example: 1.66 4TH GEAR Example: 1.23 5TH GEAR Example: 1.00 6TH GEAR Example: 0.85 FINAL DRIVE Example: 3.07 RPM REDLINE Example: 6800 - NO Commas, default is 7000   TORQUE PEAK The RPM where you want upshifts to land* * Since you want to utilize the maximum amount of torque your engine can provide, you may want to subtract 500-1000+ RPM from your exact maximum torque peak field to broaden the powerband you will use while accelerating. This will keep you in your engine's "sweet spot" longer. RPM 1st 2nd 3rd 4th 5th 6th 8000 0 0 0 0 0 0 7500 0 0 0 0 0 0 7000 0 0 0 0 0 0 6500 0 0 0 0 0 0 6000 0 0 0 0 0 0 5500 0 0 0 0 0 0 5000 0 0 0 0 0 0 4500 0 0 0 0 0 0 4000 0 0 0 0 0 0 3500 0 0 0 0 0 0 3000 0 0 0 0 0 0 2500 0 0 0 0 0 0 2000 0 0 0 0 0 0 1500 0 0 0 0 0 0 1000 0 0 0 0 0 0 These calculations are based on mathematical formulas for circumference and rotating distance over time. There are many factors which can affect the real-life performance such as tires, weight deflection, shift delay, etc. Your results may vary. The shift calculator is based on upshifting from a lower gear to the next higher gear at the same speed ensuring that the shift drops the engine speed to the torque peak RPM given, if possible. High torque peaks result in a shift at redline. Since powerbands on most engines cover a larger area than a single RPM point, again, your results may vary. This is for entertainment/information purposes only and should be used accordingly at your own risk!