Measure My — Measure what you see.
A precision ruler and measurement toolkit for anything on your screen. Press ⌃⌥M, and ten instruments lie right over the app you’re in — reading real pixels, to the pixel.
Free to download · Requires macOS 15 or later
Straight Ruler. Lay a ruler on anything and read its length. Free forever.Corner Ruler. An L-square that reads width and height from one corner at once.Caliper. Point-to-point distance, with ΔX and ΔY for diagonals.Rectangle Frame. Width × height and aspect ratio of any rectangular area.Circle Gauge. Diameter and radius of round things — avatars, icons, buttons.Crosshair. Exact pixel coordinates anywhere, with an optional origin.Gap. The spacing between two elements, horizontal or vertical.Angle. A protractor for angles between 0° and 180°.Grid. Column, baseline, square and dot grids across the whole screen.Pixel Probe. One pixel, magnified — with its exact coordinates.
Ten instruments
The right instrument for every measurement.
Distance, corners, circles, spacing, angles and pixel-perfect alignment — each one a crafted object you place on the screen like the real thing.
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 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 moreHow it works
Placed right on the screen.
Drag, rotate and position precision tools as naturally as using a physical ruler.
- 1
Press ⌃⌥M.
From any app. The instruments lie over your screen — every display — without switching apps.
- 2
Place an instrument.
Choose one with a number key or the tool rail, and drag it onto what you want to measure. The rest of the screen stays clickable.
- 3
Read it. Copy it.
The readout updates as you move. ⌘C copies the measurement; Esc puts everything away.
Styles
Instruments you’ll enjoy using.
Each instrument is a crafted object — tinted glass lit from above, engraved marks and shadows that fall straight down. Choose from four styles.
Measure My Pro adds eight accent colours, readout sizes, shadows and grid opacity. Press S to switch styles while you measure.
Precision
Made for details.
Use precision tools for tiny measurements, sharp edges and exact spacing.
Real pixels, on every display.
Pixels means your display’s real device pixels, so readouts match your screenshots: 160 points read 320 px on Retina. Ticks stay razor-sharp on every display, and instruments can straddle two screens.
Points, centimetres and inches.
With Measure My Pro, switch units with U. Centimetres and inches appear on displays that report their size, or after a quick calibration with a bank card or a 10 cm ruler.
Enhanced Precision.
Optional and free: edges snap, gaps are found as you hover, frames fit with ⌘-click, and the loupe shows real magnified pixels. It uses one still image, only while you measure, and never leaves your Mac.
Copy what you measure.
⌘C copies a clean value — “240 px”, “320 × 200 px”, “45°” — without ever stealing a copy meant for the app underneath.
Keyboard
Ready when you are.
Press ⌃⌥M anytime to measure what’s on screen. Every instrument is a keystroke away, and every handle can be moved with the keyboard.
- ⌃⌥M
- Show or hide the instruments, from any app
- 1–0
- Choose an instrument
- ←→↑↓
- Nudge by 1 px (⇧: 10 px)
- ⌥←→
- Resize the instrument
- []
- Rotate by 1° (⇧: 15°)
- A
- Alternate: swing, swap, next corner, next mode
- U
- Next unit
- L
- Toggle the loupe
- S
- Next style
- ⌘C
- Copy the measurement
- ?
- Show every shortcut
- esc
- Put the instruments away
Privacy
Nothing you measure ever leaves this Mac.
No account, no analytics, no tracking and no third-party code. Every instrument works without a single permission.
No data collected.
The App Store privacy label says it plainly: Data Not Collected.
No permissions needed.
The shortcut, the overlay and all ten instruments work without asking for anything.
One optional permission.
Only Enhanced Precision uses Screen Recording — one still image, in memory, discarded when you’re done.
No account. No subscription.
Download it and measure. The only network use is Apple’s App Store, when you buy.
Never requested: Accessibility, Input Monitoring, Full Disk Access, camera, microphone, contacts or location. Read the Privacy Policy ›
Free & Pro
The ruler is free. Forever.
Free measurements are never degraded: the free ruler is pixel-exact, snaps like any other, and reads the same numbers as the paid one.
Measure My
Free
- The straight ruler, pixel-exact, at a fixed 640 points
- Real device-pixel readouts
- The Crystal style
- Enhanced Precision: edge snapping, gap detection and the loupe
- The shortcut, menu bar, every display and full keyboard control
- VoiceOver, Voice Control and text up to 200%
Measure My Pro
One-time purchase
- All nine other instruments, for good
- Resize the ruler freely
- Points, centimetres and inches
- Display calibration for real centimetres and inches
- Four styles, eight accents
- Readout size, shadows and grid opacity
- Reopen the instrument you used last
Each Pro instrument opens once for a full session, so you can try it on your own work before you buy.
Measure My Pro is a one-time in-app purchase on the Mac App Store — no subscription, no account, nothing to renew.
FAQ
Questions? Measured answers.
How do I measure pixels on my Mac screen?
Press ⌃⌥M to show Measure My’s instruments over any app, then lay the ruler — or any other instrument — on what you want to measure. Readouts are in real device pixels, so they match your screenshots exactly.
Is there a built-in ruler on the Mac?
macOS doesn’t have an on-screen ruler. Measure My adds ten measuring instruments that lie over your screen with one shortcut, and the straight ruler is free forever.
How do I measure the distance between two elements?
Use the gap tool to measure the space between two edges, or the caliper to measure between any two points. With the free Enhanced Precision, gaps are detected automatically as you hover.
Why does something 160 points wide read 320 pixels?
On a Retina display, every point is two device pixels. Measure My reads real pixels by default so numbers match screenshots; Measure My Pro can also show points.
Can I measure in centimetres or inches?
Yes, with Measure My Pro. They appear on displays that report their physical size, or after you calibrate the display with a bank card or a 10 cm ruler held against the screen.
Does it work with more than one display?
Yes. The instruments cover every display, can be dragged between screens or left straddling two, and stay sharp on Retina and standard displays alike.
Is Measure My free?
Measure My is free to download, and the straight ruler, pixel readouts, the Crystal style and Enhanced Precision are free forever. Measure My Pro is a one-time purchase that adds the other nine instruments, more units and the other styles. Each Pro instrument opens once for a full session so you can try it first.
Does Measure My need Screen Recording permission?
Only if you turn on Enhanced Precision, which is optional. It uses one still image of the screen while you measure, keeps it in memory and discards it when you close the instruments. Everything else works without any permission.
Does Measure My collect any data?
No. There’s no account, no analytics, no tracking and no third-party code. Its App Store privacy label is Data Not Collected.
Can I use it while working in other apps?
Yes. Only the instruments and their readouts catch the mouse; everything else on the screen stays clickable and scrollable underneath, and Measure My never takes you away from the app you’re in.
What do I need to use Measure My?
A Mac with macOS 15 or later. Measure My is available in English, Italian, Spanish, French and Simplified Chinese.
Measure what you see.
A precision instrument for your screen — one shortcut away.
Free to download · Requires macOS 15 or later