A lightweight screenshot app for Mac, with numbers

A capture app runs all day so that it is there the moment you need it. That makes its idle cost matter more than almost any other app's. Here is what to look at, how to check any app yourself, and what Lightcap measures.

What lightweight should mean

Memory while idle. What the app holds when you aren't using it. This is the cost you pay all day.
CPU while idle. It should be zero. An app that wakes up on a timer drains battery even when you do nothing.
Time from shortcut to capture. A delay here is the one you actually feel.
Download size. A rough sign of how much is bundled inside. Apps built on a web runtime are usually much larger than native ones.

How to check any app yourself

Open the app and leave it alone for a minute.
Open Activity Monitor (in Applications > Utilities) and find the app by name.
On the Memory tab, read the Memory column. Check for helper processes with a similar name and add them up.
On the CPU tab, watch % CPU for a while. An idle menu bar app should sit at 0.0.
On the Energy tab, look at the 12 hr Power column after a day of normal use.

Do the same for any two apps you are choosing between, on your own Mac. That comparison is worth more than any number on a website, including ours.

What Lightcap measures

Download	Memory while idle	CPU while idle	Time to capture an area
3.3 MB	22 MB	0%	0.03 s

Measured by us in November 2026 with the Lightcap 0.1 release build on a MacBook Pro (M3 Max) running macOS 27.2. Download size is the DMG. Capture time is the time to grab an 800×500 area after it is selected; it leaves out saving the file and the first capture after launch. Your numbers will vary.

How it stays small

Native code only. Lightcap is written in Swift with the system frameworks. There is no bundled browser or runtime.
Nothing runs until you press a shortcut. Windows such as the editor and settings are created when you open them and released when you close them.
Recording doesn't render. Video goes straight to disk through the hardware encoder. Zooms and effects are applied only when you export.
Text recognition runs in a short-lived helper. It starts when you copy text and exits afterwards, so the memory it needs is given back.

What you get in 3.3 MB

Area, window, full screen and scrolling screenshots, copied to the clipboard as you take them.
Screen recording, and an editor with trim, cut and automatic zoom on clicks. Export as MP4 or GIF.
Copy text from anything on screen (Korean, English, Japanese, Chinese and more).
Pin a screenshot above other windows, and annotate with arrows, boxes, text and blur.

It does not have cloud sharing, a webcam overlay or system audio.

Questions

How much memory does Lightcap use?

About 22 MB while idle in the menu bar, measured by us in November 2026 with the 0.1 release build on a MacBook Pro (M3 Max) running macOS 27.2.

How do I check how much memory a Mac app uses?

Open Activity Monitor, find the app by name, and read the Memory column on the Memory tab. Add up any helper processes with a similar name.

Download Lightcap for Mac and try every feature free for 7 days. No account or card needed. It runs on macOS 15 or later.