Online RulerRead inches on screen
Select inches in AR Ruler and line up one end of the object with the zero mark. Look straight at the ruler and read the tick under the other end. Use the last whole inch you passed, followed by any fraction shown by the ticks between the whole-inch marks.
- The numbered ticks mark whole inches. The shorter ticks between them mark fractions of an inch.
- The movable marker uses the ruler’s zero as its starting point. Move it to the far end to help read the span.
- The screen scale depends on calibration. Check it with your bank card after a browser zoom or display change.
- Open the calibrated ruler and select inches. Set the object against the display where you can see the numbered marks and the shorter ticks.
- Place the starting edge at zero and keep the length you want to measure parallel to the ruler. Align the edge with the center of the zero tick.
- Slide the marker to the far edge, or read the tick directly beneath that edge. Keep the starting edge at zero while you do this.
- Write down the whole inches and the fractional part in inches. If the edge lies between marks, record the nearest marked value or the two marks it falls between.
Read the fraction
Find the two numbered marks on either side of the far edge. The mark halfway between those numbers stands for half an inch past the lower number. From there, look at the smaller spaces in that same inch. Count equal spaces from the lower number to the edge. Use that count as the top of the fraction and the total count of equal spaces in the inch as the bottom. Start counting with the space immediately after the numbered mark.
Read the edge straight on
Move your eyes in front of the far edge before deciding which tick it meets. This is especially helpful when the part you are reading sits above the screen. Look at the point where the object ends along the direction of the ruler. For a rounded end, use the outermost point in that direction. If you shift the object to see the mark, put its starting edge back at zero before taking the reading.
Measure between marks
If the object covers zero or is awkward to position there, start it at a clearly labeled whole-inch mark. Read the far end from the same ruler, then subtract the starting number from that reading. Keep the fractional part when you subtract a whole number. The movable marker still shows a value measured from zero, so treat it as the far-end reading when you use this method.
What if the edge lands on a numbered tick?
Record the number beside that tick in inches. A reading on a whole-inch mark needs no fractional part.
What if the object extends past the visible scale?
Measure successive spans using a visible tick as each stopping point. Carry that point over as the start of the next span and add the readings.
Will browser zoom give me a finer reading?
Zoom changes the displayed scale. Verify the calibration at the new zoom and report the reading using the marks you can see.