How to Track App Usage on Mac: 3 Methods Compared

"How long did I spend in Xcode today?" is a simple question with three increasingly involved ways to answer it on macOS. Each has a valid use case; each has limits that are worth knowing before you commit.

This post walks through all three — the built-in Screen Time, a DIY approach with Hammerspoon or osascript, and a dedicated tracker — with a table at the end for quick reference.

Method 1: Apple's Screen Time (built-in, good for a rough read)

Screen Time, buried in System Settings → Screen Time → App Usage, gives you:

• Per-app time totals for today, yesterday, this week, this month.
• A grouped pie chart by Apple-assigned category.
• Per-device aggregation if you're signed into iCloud across a Mac + iPhone + iPad.

What it does well: It's free, zero setup, and if your question is "roughly, which apps did I use today?", it answers that. The per-day roll-up is fine.

Where it breaks down:

• Counts time while the app is frontmost, regardless of whether you were at your desk. Overcounts heavily on days when you stepped away with an app in focus.
• Only sees inside Safari for URLs. If your day is mostly Chrome or Arc, the most important detail (which sites) is missing.
• No focus score, no session length, no switch count — just totals.
• Not categorizable per your own definition of productive.
• Can't export raw data.

Use it when: You want a quick ballpark check and you're a Safari user. Also fine for monitoring a kid's or teen's device, which is what it was designed for.

Don't use it when: You need per-site detail across browsers, you care about actively engaged time (not just foreground time), or you want any notion of focus vs. fragmentation.

Method 2: DIY with Hammerspoon (or osascript + cron)

For developers who want to roll their own, Hammerspoon is a powerful Lua-scriptable macOS automation tool that can watch the active window and log it. A minimal script looks like:

-- Watch active window changes and log app name + timestamp to a CSV
local log = io.open(os.getenv("HOME") .. "/app-usage.csv", "a")

local lastApp = nil
hs.application.watcher.new(function(name, event, app)
  if event == hs.application.watcher.activated then
    local now = os.date("%Y-%m-%d %H:%M:%S")
    log:write(now .. "," .. name .. "\n")
    log:flush()
    lastApp = name
  end
end):start()

That writes one row per app activation to a CSV. You then post-process in a spreadsheet or with awk to compute per-app time.

A shell-only version works too:

# runs every 30 seconds via a launchd job
osascript -e 'tell application "System Events" to get name of first application process whose frontmost is true' \
  >> ~/app-usage.log

What DIY does well:

• You own the script, the schedule, the data format.
• Nothing unusual to install. Hammerspoon is well-trusted in the Mac power-user scene.
• Zero recurring cost, zero privacy leakage.

Where DIY breaks down:

• You have to build idle detection yourself (check HID input via IOKit).
• URL tracking requires separately calling osascript into each browser and handling each browser's quirks. Non-trivial.
• No UI. You'll be looking at CSVs in a spreadsheet or writing your own dashboard.
• Reliability edge cases (system sleep, fast user switching, app crashes) are all on you.

Use it when: You're a developer who wants total control and doesn't mind writing the code. Or you want to prototype what a full tracker would surface before paying for one.

Don't use it when: You just want data today without building infrastructure, or you want per-browser URL tracking, or you want visual reports.

Method 3: A dedicated tracker (Focus Meter, Timing, RescueTime)

The managed option: install a purpose-built tracker, grant the permissions, and get the full feature set without writing code.

The three main categories:

What a dedicated tracker does well:

• Per-app time with activity-based idle detection (not just foreground time).
• Per-site time in all major browsers, not just Safari.
• Categorization against your own productive / neutral / distracting labels.
• Focus score, session length, context switches — actual focus metrics.
• Reports UI with trends, comparisons, export.

Where a dedicated tracker costs you:

• Money: $19–$150+/year depending on pick.
• Permissions: Accessibility and Automation, typically.
• Learning curve: a few minutes to set up categorization.

Use it when: You actually care about the data, not just a ballpark. Which, given the overhead of setting any of this up, is probably why you're here.

Don't use it when: Screen Time's rough totals are enough for your use case, or you're philosophically committed to only using tools you built yourself.

Side-by-side summary

How to pick

If you're answering "what should I use to track app usage on Mac?" right now and you don't already have a tool in mind:

• Just want the ballpark for today? Open Screen Time. Close it. Move on.
• Want to learn how macOS's activity tracking internals work, or want total control? Install Hammerspoon and write a script. Factor in a weekend.
• Want the data useful for actual focus decisions, today, without writing code? Install Focus Meter. Five minutes of setup. $19. On-device.

The correct answer depends on whether you want to answer a question or build a system. Screen Time and a dedicated tracker answer the question. DIY builds a system. All three are legitimate uses of your time.