Caliper · 3 Pro
Measure the distance between two points.
Set the two jaws on any two points and read the distance between them. When the line runs at an angle, the caliper also shows how far apart they are horizontally and vertically.
Free to download · Requires macOS 15 or later
What it measures
- The straight-line distance between any two points
- Horizontal and vertical offsets (ΔX, ΔY) for diagonal measurements
- The angle of the line between the points
- Spacing between elements that don’t share an edge
How to measure a distance with the caliper
Choose the caliper
Press ⌃⌥M, then 3.
Set each jaw on a point
Drag a jaw onto each point. Hold ⇧ to keep the line at 45° steps. Press A to swap the ends.
Read the distance
The readout shows the distance; when the line is diagonal it adds ΔX, ΔY and the angle. Press ⌘C to copy it.
Keyboard shortcuts
- 3
- Choose the caliper
- A
- Swap the ends
- ⌥←→
- Shorten or lengthen
- []
- Rotate around the centre
- ⌘C
- Copy the distance
Free or Pro?
The Caliper 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 distance between two points on my screen?
Use Measure My’s caliper: drag one jaw to each point and read the distance. For a diagonal it also shows the horizontal and vertical distances (ΔX and ΔY).
What’s the difference between the caliper and the ruler?
The ruler measures along its own edge, like a physical rule. The caliper measures between two points you set — handy when the points aren’t on a straight edge you can lay a ruler against.
The other instruments
Straight Ruler
Free Lay a ruler on anything and read its length. Free forever. Learn moreCorner Ruler
Pro An L-square that reads width and height from one corner at once. 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.