Online RulerMeasure a Photo’s Short Edge
Set the photo print flat and measure the shorter paper edge from corner to corner. Include any white border when you need the size of the whole print. For the size of the picture alone, place the ruler at the edges of the printed image and measure that span separately.
- Turn the print until its short side lies along the ruler. The direction of the picture can stay sideways or upside down.
- Start at the zero mark. The edge of a printed scale may have blank paper before zero.
- Use one unit for any dimensions you plan to write down together. To convert between inches and millimeters, use 1 in = 25.4 mm.
- Put the print face up on a clean, flat surface. Compare the two adjacent edges to find the shorter one. If they look equal, measure both before deciding which reading to record.
- Choose centimeters or fractional inches on a calibrated AR Ruler screen, or place a verified paper scale beside the print. Use a scale that reaches from one corner to the other.
- Line up the short edge of the print with the scale. Place the first corner at zero on screen or shift the paper scale to line up zero with that corner. Keep both corners on the same line. On screen, move the marker to the second corner.
- Read the mark at the far corner while looking straight down. If you also need the size of the visible picture, line up zero with the image boundary and take a separate reading at the opposite boundary.
Paper and picture
Measure the paper when you need to know how much room the whole print takes up. Start at the cut edge and include the border. To measure the picture, start where the image begins inside the border. If the border varies from side to side, keep the ruler parallel to the edge and note where you took the image reading.
Keep the print flat
If a corner curls, hold the print lightly farther in from the edge while you line up the ruler. Keep the starting and ending corners in view. For rounded corners, follow the straight sides with your eye to where they would meet. Use those points for an approximate reading of the full paper width.
Check a printed ruler
Print the AR Ruler page at actual size. Measure its 10 cm test line with a physical ruler before using the page. If the line comes out a different length, check the print scaling and try again. Keep the print and the paper ruler on the same flat surface so neither edge sits above the scale.
Can I measure a photo through its frame?
You can measure the visible opening. To get the full paper size when the frame or mat covers an edge, take the print out and measure it flat.
Where do I read a thick zero line?
Line the first corner up with the center of the zero tick. Read the far corner against the centers of the ticks at that end.
What if the print is square?
Measure two adjacent sides. If they read the same on your scale, record the side length and call the print square.