Rectangle Frame · 4 Pro
Measure any rectangle — and its aspect ratio.
Draw a frame around any area to read its width, height and aspect ratio, with dimension lines like a technical drawing.
Free to download · Requires macOS 15 or later
What it measures
- Width × height of any area
- Aspect ratio, reduced to a simple ratio like 16:9 when it can be
- The top-left origin coordinates, when Show Coordinates is on
- Images, videos, screenshots, windows and layout regions
How to measure an area with the frame
Choose the frame
Press ⌃⌥M, then 4.
Draw or fit it
Hold ⌘ and drag on empty space to draw a frame — ⇧ makes a square, ⌥ draws from the centre. With Enhanced Precision, hover an element and ⌘-click to fit the frame to it.
Adjust and read
Drag a corner or an edge to resize; ⇧ keeps the aspect ratio. Read width × height and the ratio, and press ⌘C to copy.
Keyboard shortcuts
- 4
- Choose the frame
- ⌘drag
- Draw a new frame
- ⇧
- Keep the aspect ratio while resizing
- ⌥←→↑↓
- Resize the width or height
- ⌘C
- Copy “W × H”
Free or Pro?
The Rectangle Frame 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 find the aspect ratio of something on my screen?
Draw Measure My’s frame around it. Along with width × height, the readout shows the ratio — reduced to a form like 16:9 when both numbers are small enough, or as a decimal otherwise.
Can the frame snap to an element automatically?
Yes, with Enhanced Precision on: hover outside the frame to preview the detected region, then ⌘-click to fit the frame to it.
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 moreCaliper
Pro Point-to-point distance, with ΔX and ΔY for diagonals. 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.