Ruler Online Free shows a real, life-size ruler on your screen — calibrated to your exact display so measurements are accurate, not just pixels.
→ cm, mm, and inches on the same ruler
→ Calibrate by entering your screen size or PPI
→ Print to PDF (12-inch, 8-inch, protractor)
→ No signup, no ads, no install
Works on any device with a modern browser.actual size.
