Choose by the job, not by a promised battery saving
These tools prevent particular kinds of sleep. They do not make an export, download or backup intrinsically faster, and they are not battery optimizers. Keeping the system or display awake can increase energy used compared with letting that part sleep.
This is a comparison of documented behavior. We did not install these apps or measure a keep-awake session for this page. No fixed wattage penalty or runtime improvement is claimed. A video export and an idle download can have very different power use even with the same sleep control.
If you want a persistent macOS preference instead, the stop-sleeping guide covers the built-in settings. Avoid changing a system preference permanently when a session that ends automatically would solve the actual task.
| Need | Start with | Why |
|---|---|---|
| One Terminal task or a timed window | caffeinate | Built into macOS; the assertion ends with the process or timeout. |
| Rules based on an app, device or power condition | Amphetamine | A graphical trigger system and session controls. |
| A simple on/off menu icon | Caffeine | A small toggle with optional timed deactivation. |
Built in: caffeinate
Apple’s local manual describes caffeinate as a utility that creates power-management assertions on behalf of a task. With no flags, it prevents idle system sleep while it runs. An assertion requests a particular sleep behavior; it does not disable every reason a Mac might sleep or shut down.
Read the installed manual without changing anything:
man caffeinateFor a temporary one-hour idle-sleep assertion, the reference command is:
caffeinate -i -t 3600-i prevents idle system sleep and -t sets a timeout in seconds. It needs no sudo. The assertion ends when the command exits or its timeout expires; press Control-C in that Terminal to end it early. The display can still sleep with this example.
If the task specifically needs the display awake too, -d requests that separately. For example, caffeinate -di -t 3600 adds display wakefulness to the same timed system assertion. Keep the extra display request only when it is useful. It can leave a screen showing information longer than expected.
The manual also supports wrapping a utility: an assertion then lasts for that utility’s execution. That is useful for a command-line job with a clear finish. Use a command you understand rather than pasting a generic example that downloads or changes files.
We read the manual on macOS 27.0.1; we did not start an assertion or change sleep settings for this comparison. None of these commands is presented as a way to override a closed lid, depleted battery, thermal protection or an administrator’s policy.
Where Amphetamine is stronger
Amphetamine gives you a graphical session you can start indefinitely, for a duration or until a time. Its App Store description also documents sessions associated with an app or download, and triggers based on conditions such as an external display or power connection. Those are useful when the task is easier to describe as a rule than as a Terminal command.
You can distinguish keeping the Mac awake from allowing the display to sleep. Its documented choices include automatic session ending at low battery. That makes it more capable than a plain manual toggle, but review the chosen trigger so it does not keep starting a session after the original job is finished.
Price, version and support: Amphetamine is free, with no paid Pro tier or in-app purchase listed by the developer. The App Store shows 5.3.2, 10 November 2023. Its current compatibility field requires macOS 10.13 or later, despite older descriptive text saying 10.11. The release notes explicitly discuss Apple silicon support; they do not provide a separate complete architecture list.
Watch out for: closed-display features can involve separate scripts such as the developer’s Power Protect. They are distinct from a basic timed session. This page does not instruct you to install those scripts or assume they work identically on every macOS release.
Where Caffeine is stronger
The Caffeine compared here is IntelliScape Solutions’ edition, continued from the original Lighthead Software project. Its maker describes a coffee-cup menu icon: click to keep the Mac awake, click again to return to ordinary sleep, or use its menu for a timeout. That is a focused choice when you want a visible manual toggle.
Price, version and support: it is free, with donations offered. The maker’s official GitHub release is 1.1.4, 22 September 2025 UTC. Its notes add native Apple silicon support and fixes for macOS 26 Tahoe. The maker’s website returned an error during our direct check, and the repository’s older README does not establish the current minimum macOS version. Confirm the current download requirements before installing; macOS 27 support and a complete Intel compatibility list were not verified.
Watch out for: multiple projects use the name Caffeine. A separate fork can have a higher version number and different requirements. Match the developer and source rather than assuming every App Store or download-site result is the edition described here.
If you only need a one-off job, Caffeine’s simplicity may still be more app than necessary: caffeinate is already present. If you need condition-based automation, Amphetamine’s documented trigger system is the more relevant comparison.
Display sleep, locking and a closed lid
Keeping the system awake does not require leaving the display lit for every job. Let the display sleep when you do not need to watch progress. Keep your usual screen-lock protection; a keep-awake task is not a reason to disable authentication or leave private material visible.
A closed MacBook is another case. The ordinary supported closed-display setup has hardware and power requirements. Use the clamshell guide for that workflow. Do not test an unfamiliar lid-override tool by placing a working, hot MacBook into a bag.
If a Mac sleeps despite a session, identify which kind of sleep occurred and whether the session ended. An idle timeout, closed lid, shutdown or lost power are different events. Repeatedly adding persistent power-setting commands can obscure the original problem and make normal sleep harder to restore.
What staying awake costs in energy
There is no honest universal “Amphetamine costs X watts” figure here. The total depends on the active workload, display, attached devices and the state the Mac would otherwise have entered. Comparing only the tiny utility’s own CPU use misses the system work it keeps running.
To assess your own routine, keep the task, screen brightness, accessories and power source consistent. Observe the system draw and task progress during a needed session, then end it and confirm that normal sleep returns. This is a way to make a local observation, not a benchmark result from this guide.
For an unattended transfer, choose a timer or end condition long enough for that task and check the result afterward. Remove a persistent trigger you no longer need. Normal sleep is useful; keeping a Mac awake by default spends energy even after the original reason has disappeared.
Where Tend fits
Tend’s free menu bar watts and current app estimates can put an awake session’s activity in context. Energy over time gives 24-hour period totals for free, with 7 and 30 days in Pro. They are not a promise to measure every sleep interval or isolate a utility’s causal overhead.
Tend does not replace Amphetamine, Caffeine or caffeinate as a keep-awake controller. Use the watts guide to interpret readings, and end the session in the tool that created it.
Questions
Which is better, Amphetamine or Caffeine?
Amphetamine has more documented automation and session rules. IntelliScape’s Caffeine focuses on a simple menu toggle and timeout. For one temporary job, built-in caffeinate may be enough.
Does caffeinate need sudo?
The timed idle-sleep examples here do not. They create temporary assertions that end when the process or timeout ends; Control-C stops the foreground command early.
Does keeping a Mac awake save battery?
That is not the job of these tools. Preventing normal sleep can use more energy, with the effect depending on the workload and whether the display stays on.
Related guides
Mac sleep settings
Choose a temporary or persistent change.
Closed-display mode
Use the supported hardware setup.
Sources
- Apple, local
man caffeinate, read on macOS 27.0.1; no sleep assertion was started. - William Gustafson, Amphetamine App Store description, version history and compatibility.
- IntelliScape Solutions, Caffeine, official GitHub releases and project README.
See what is taking space on your Mac
Tend is free to download. Pro is $1.99 a month, $12.99 a year with a 7-day free trial, or $29.99 once.