PlanDeskHow to set the scale on a PDF drawing (or calibrate it)
A PDF doesn't know what scale it was drawn at, so every measuring app asks you to tell it. There are two ways: pick the printed scale, or calibrate against a dimension you already know. Calibrating is the safer choice when a set was printed half size, scanned or exported oddly.
Pick the printed scale
Tap the ruler button at the bottom (No scale), or choose Tools › Set scale. Pick from the Architectural, Engineering or Metric lists, like 1/8" = 1'-0" or 1" = 20'.
Or calibrate against a known dimension
In the same window tap Calibrate on the sheet (or Tools › Calibrate). Drag along a dimension you know, like a 30'-0" grid line, then type its real length in feet and inches, inches or meters and tap Set scale.
Apply it to the set
Check Apply to all sheets to use the same scale on every sheet. Sheets drawn at a different scale can each have their own.
Check it
Measure something with a printed dimension. If it's off, the sheet was probably printed at a different size: calibrate instead.
Tips
- Detail sheets often mix scales. Set the scale that matches the view you're measuring, or calibrate on that view.
- The scale is saved with the sheet, and it carries forward when you slip sheet a new revision.