Corner Ruler · 2 Pro
Measure width and height from a corner.
Like a carpenter’s square for your screen: two graduated arms meet at a corner and read the width and height of anything at the same time.
Free to download · Requires macOS 15 or later
What it measures
- Width and height from one corner, in a single readout
- The size of cards, panels, images and windows
- Any of the four corners — press A to swing to the next one
- Rotated shapes, with an angle readout when tilted
How to measure with the corner ruler
Choose the corner ruler
Press ⌃⌥M, then 2. The square opens with its arms to the right and down.
Place the measuring corner
Drag the inner corner onto the corner of the element. With Enhanced Precision, it lands right on the element’s edges.
Read width × height
The readout shows both, for example “320 × 200 px”. Drag an arm’s end to lengthen it, and press A to move to the next corner of the same shape.
Keyboard shortcuts
- 2
- Choose the corner ruler
- A
- Swing to the next corner
- ⌥→
- Lengthen the horizontal arm (⌥← shortens it)
- ⌥↓
- Lengthen the vertical arm (⌥↑ shortens it)
- ⌘C
- Copy “W × H”
Free or Pro?
The Corner Ruler is part of Measure My Pro, a one-time purchase. Before you buy, it opens once for a full session, so you can try it on your own work.
Enhanced Precision — edge snapping, gap detection and a real-pixel loupe — is free and optional. It needs Screen Recording permission; everything else works without it.
Questions and answers
How do I measure the width and height of something on my Mac screen?
Place Measure My’s corner ruler on one of its corners. Both arms are graduated from that corner, so the readout gives width and height together — for example “320 × 200 px”.
Can it measure from any corner?
Yes. Press A to swing the square to the next corner of the same rectangle: top-left, top-right, bottom-right, then bottom-left.
The other instruments
Straight Ruler
Free Lay a ruler on anything and read its length. Free forever. Learn moreCaliper
Pro Point-to-point distance, with ΔX and ΔY for diagonals. Learn moreRectangle Frame
Pro Width × height and aspect ratio of any rectangular area. Learn moreCircle Gauge
Pro Diameter and radius of round things — avatars, icons, buttons. Learn moreCrosshair
Pro Exact pixel coordinates anywhere, with an optional origin. Learn moreGap
Pro The spacing between two elements, horizontal or vertical. Learn moreAngle
Pro A protractor for angles between 0° and 180°. Learn moreGrid
Pro Column, baseline, square and dot grids across the whole screen. Learn morePixel Probe
Pro One pixel, magnified — with its exact coordinates. Learn more
Measure what you see.
A precision instrument for your screen — one shortcut away.