"We math so you don't have to."
Add and subtract tape measurements in inches or millimeters, then divide the total. Leave divide by at 2 to find the center.
Enter a run of measurements in the Run box. Each measurement can be a decimal (19.25), a fraction (3/16), or a mixed number (19-1/4 or 19 1/4). A measurement without mm is inches. 100mm and 100 mm are millimeters.
The + and − buttons insert addition and subtraction. 12.25 + 1 + .25 - .75 totals 12-3/4". The hyphen in 19-1/4 is part of the measurement, not a minus. The mm button marks the current measurement in millimeters, and a second press removes that mm. 12.25 + 100mm + 1.25mm mixes inches and millimeters.
Divide by splits that total. It starts at 2, which marks the center. Each answer shows the exact length in inches, in feet and inches, and in millimeters. Round to nearest starts at 1/16". When the fraction does not land on that mark, the nearest length is shown too.
The fraction ruler under each answer is one inch, marked at the round-to-nearest setting. The ruler above Divide by shows the fraction of the total. The ruler below shows the fraction after dividing. A mark between the ticks is the exact fraction, and the highlighted tick is the nearest mark.