Online RulerCalibrate with a case on
Keep the case on if your reference card can rest flat over the part of the display you use. If the case lip props up the card or hides its edge, move the card inside the lip or remove the case. Look straight down at each edge as you line it up with the screen marks.
- The nominal ISO ID-1 bank card dimensions are 85.60 mm wide and 53.98 mm high.
- The website and desktop extension save the calibration locally. They take no card data, upload nothing, and use no sensors for calibration.
- A raised lip or a gap above the display can make an edge appear to shift when you view it from the side.
- Set the device on a stable surface and open the AR Ruler calibration at the browser zoom and display settings you plan to use.
- Place the card flat on the display or protector. Check that it lies inside the raised rim and that the case leaves the card edge and the alignment marks visible.
- Follow the calibration prompts. Match the long edge when asked for the width and the short edge when asked for the height. Use the straight part of the edge as your reference.
- Look directly above each alignment point and shift your head along the card as needed. Lift the card, then set it back down and compare the same span with the ruler.
- Place the object flat in the clear area of the display. If its near edge lines up with zero, look straight down and move the marker to the far edge. Otherwise, read both edges with the marker and subtract the smaller reading from the larger.
Work around the case lip
A case can hold one side of the card above the screen, especially when the card stretches across the rim. Press lightly near each end to see whether the card rocks. Slide it to a clear area if the calibration marks are still visible there. Take the case off if it prevents the card from lying flat. Check that the object you measure can rest flat too, since its shape may catch on the lip in a different place.
Read through a protector
Leave a flat protector in place if you can see the scale clearly through it. The scale is drawn on the display below the surface where the card rests. Viewed from the side, a card edge can appear over a different tick. Move your head over the mark you are reading. If glare covers that mark, change the lighting or turn the device on the table.
Check after a change
When AR Ruler detects a browser zoom or display change, it discards the stored scale. Compare the ruler with the same card edge after a change and repeat calibration if the marks fail to line up. After changing a case or protector, check that the card still sits flat and that both endpoints line up when viewed from above.
Should I line up a rounded corner?
Use the straight edge. A rounded corner curves away from the line you are trying to match.
Do I need to show the card number?
You can place the card face down. Only its physical edge matters for the comparison.
Why does the reading change when I lean over?
Your viewing angle changes where the raised edge appears against the display. Put your eye above the mark and read it again.