Online RulerWhy Zoom Changes a Ruler
Browser zoom changes how much space the ruler’s marks take up on the screen. A scale that matched a physical reference at one zoom setting can look longer or shorter at another. Set the zoom you plan to use, then verify the ruler against a physical reference before measuring.
- The AR Ruler website and desktop or browser extension ruler show centimeters or fractional inches after calibration.
- Card calibration is saved locally. The ruler takes no data from the card and uses no upload or sensors for this check.
- When AR Ruler detects a browser zoom or display change, it clears the saved scale. Check the ruler after a change, even if it shows no prompt.
- Open AR Ruler on the screen you plan to measure on. Set the browser zoom where you want it before starting calibration.
- Open card calibration and hold a standard bank card flat against the display beside the calibration guide.
- Adjust the guide to match the card edges it shows, then save the calibration at that zoom setting.
- Compare the on-screen marks with a physical ruler if you have one. Align zero with zero and look at a mark farther along the scale.
- After changing zoom, switching displays, or adjusting display scaling, compare again. Repeat the calibration if the marks no longer line up.
What changes with zoom
Zoom resizes the page, including the space between the ruler’s marks. The centimeter and inch labels stay the same while the marks can move farther apart or closer together. Moving the ruler window to another display can also change the physical spacing. Check the scale on the display where you will use it.
Match the card edges
The nominal ISO ID-1 bank card size is 85.60 mm wide and 53.98 mm high. Use the straight edges to judge alignment, especially if the corners are rounded. Hold the card still and look straight at the screen as you adjust the guide.
Move the reading marker
Once the scale is set, line up the near edge of the object with zero at the left end. Move the marker to the far edge and read the distance in centimeters or fractional inches. If you zoom to make a mark easier to read, verify the scale again before recording the measurement.
Do I have to use 100% browser zoom?
You can calibrate at the zoom you plan to use. Check the physical spacing at that setting and repeat the check if you change it.
Why check when there is no prompt?
The ruler can respond to changes it detects. A comparison against a physical reference tells you whether the marks still match on your screen.
Do I need to enter my card number?
No. Hold the card against the screen and use its outer edges as a size reference.