Two-cycle semi-log graph paper
Two decades on the logarithmic axis, which covers a hundredfold range and keeps the divisions readable.
Opens with these settings already loaded. Change anything you like, then download as PDF, PNG or SVG.
Two cycles is often all you need
A cycle, or decade, is one factor of ten. Two of them span a hundredfold range, from 1 to 100 or from 0.01 to 1, which covers a great deal of laboratory and classroom data. Choosing more decades than your data spans is the common error: the points crowd into one corner of the sheet and you lose the resolution that made you reach for log paper in the first place.
Fewer cycles means more room per decade
The page height is fixed, so decades share it. On a two-cycle sheet each decade gets roughly half the page and the subdivisions within it are far enough apart to plot and read by eye. On a four-cycle sheet the same decade is compressed into a quarter, and near the top of each decade the divisions crowd so tightly that precise plotting stops being possible by hand.
Count your range before you choose
Take the largest and smallest values you need to plot and count the powers of ten between them. Data running from 5 to 400 spans two decades and belongs here. Data from 2 to 8000 spans nearly four and does not. You cannot extend a logarithmic axis by taping on another sheet the way you can a linear one, so this decision has to be made before you print rather than after.
Printing it accurately
This only measures correctly if your printer doesn't rescale the page. In the print dialog set Scale: 100%, not "Fit to page" or "Shrink oversized pages". If you're not sure it worked, print the calibration page, measure the ruler on it with a real ruler, and it will tell you exactly what your printer is doing to the page.