How many watts does a MacBook use? Measured

Apple's figures: idle, sleep and off

Apple publishes a Product Environmental Report for each Mac, with its power use measured at the wall in three states. These are the 115 V figures, read 20 October 2026:

Because these are measured at the wall, they include the adapter's own losses. Apple doesn't say which chip the 2023 14-inch report used; it was tested with the 67W adapter, which came with the base M2 Pro, not the M2 Max we measured below.

What Apple's battery ratings imply

Apple's battery-life figures are another source of watts. Divide the battery's watt-hours by the hours Apple quotes and you get the average draw during Apple's test. This is our arithmetic on Apple's numbers, not a measurement, and it assumes the test used the whole battery:

The two sources agree: light, steady work on a current MacBook runs at roughly 2 to 6 W, with the bigger, brighter Pro models at the top of that range. The 99.6 Wh figure for the 16-inch is Apple's "actual rating" from the footnote; the specs round it to 100.

What we measured on a busy MacBook Pro

Apple doesn't publish figures for a Mac at work, so we read our own. This is one Mac, on one afternoon:

• Mac: 14-inch MacBook Pro (2023) with M2 Max and 32GB of memory (model identifier Mac14,5), macOS 27.0.1, battery at 264 cycles and 82% Maximum Capacity.
• When: 20 October 2026, 13:56 to 14:08 local time.
• Power: on Apple's 96W USB-C adapter, which System Information reported as 94 W, with the battery held at 80% by Charge Limit and not charging. So everything the Mac used came from the adapter.
• Workload: a real working session: several developer tools and command-line jobs, Chrome and a messaging app, with the built-in display on and no external display. The CPU was 42% to 74% busy in the samples. We didn't record screen brightness.
• Method: macOS keeps running totals of the whole system's power in the battery's registry entry, PowerTelemetryData, readable with ioreg -rn AppleSmartBattery without an administrator password. Each time macOS published new totals, about once a minute, we divided the change in AccumulatedSystemLoad by the change in SystemLoadAccumulatorCount to get that minute's average draw. It's the same reading Tend uses. Apple doesn't document these fields, so treat them as a careful reading, not an official figure.

Across the twelve minutes the average was about 44 W, roughly ten times Apple's idle figure for a 14-inch MacBook Pro. Earlier the same afternoon, an iPhone was charging from one of the Mac's USB-C ports, and ioreg reported 8.5 to 12.8 W going out to it; the Mac's total input was 35 to 72 W in that period. The "CPU busy" column is a single snapshot of CPU use taken alongside each average.

What this does and doesn't show: an M2 Max at work can draw tens of watts for minutes at a time, and a phone on a USB-C port adds about ten more. It doesn't show what any other Mac, or any other workload, would draw. A MacBook Air has a far smaller chip and power budget, and the same Mac reading a web page would be much closer to Apple's single-digit figures.

What the adapter's wattage means

A 96W adapter doesn't mean a MacBook uses 96 W. It's the most the adapter can deliver, and the Mac takes what it needs to run, plus what it needs to charge the battery when charging is allowed. Our Mac drew 36 to 49 W from its 96W adapter while busy and not charging.

That's also why a smaller adapter usually works. Apple says a Mac that charges over USB-C can use "any USB-C power adapter or display, even if it provides higher or lower wattage than the adapter recommended for your Mac" (Apple, Use a power adapter with your Mac). The trade-off is headroom: if the Mac's draw approaches what the adapter supplies, it charges slowly or not at all. MacBook not charging when plugged in? has Apple's recommended adapter for each model.

What makes a MacBook use more power

• The chip at work. Exports, builds, games and video calls keep the CPU and GPU busy, which is where the tens of watts come from.
• The display. Brightness is one of the biggest settings you control; Apple's battery tests use a moderate level.
• Charging. On the adapter, the battery's charging comes on top of what the Mac uses.
• Devices on its ports. Phones, drives and other bus-powered accessories draw from the Mac. Apple's tip is to keep the Mac plugged in when you use it to charge other devices.

Low Power Mode lowers the first two; what Low Power Mode does explains the trade-off.

How to measure your Mac's watts

This prints the whole Mac's current draw in milliwatts. It only reads and needs no password:

ioreg -rn AppleSmartBattery | grep -o '"SystemLoad"=[0-9]*'

On our Mac at 14:06 it printed "SystemLoad"=38480, so 38.5 W. macOS refreshes the figure about once a minute, so run it a few times rather than once. To see what your adapter offers:

system_profiler SPPowerDataType | grep -E "Wattage|Name:"

Ours printed Wattage (W): 94 and Name: 96W USB-C Power Adapter (plus the battery's own device name). Avoid pasting the full system_profiler or pmset -g ac output anywhere public: both include the adapter's serial number.

Two things that don't give you watts: Activity Monitor's Energy Impact, which Apple calls "a relative measure of the current energy consumption of the app" (Apple), and the percentage in the menu bar. Apple's powermetrics tool reports estimated power for the CPU, GPU and other parts of the chip, but it "must be invoked as the superuser" (with sudo), and its manual page warns that its power values "are estimated and may be inaccurate". We didn't use it here.

How Tend helps

Tend shows the whole Mac's draw in watts, from the same one-minute reading, in its window or right in the menu bar, and estimates each app's share, the power it adds above your Mac's idle draw, with GPU power split by each app's GPU time. Those per-app figures are estimates, and they cover the apps and processes running as you: processes macOS runs under its own accounts, such as WindowServer and kernel_task, can't be read without administrator access, so their share stays in the whole-Mac figure. All of this is free, with 24 hours of history; Pro keeps 30 days.

Questions

Related guides

More detailed guides:

• How much power does a Mac mini use? Apple's figures

Sources

• Apple, Product Environmental Reports: MacBook Neo, MacBook Air (M5), MacBook Air (M4), MacBook Pro 14-inch (M5), MacBook Pro (M5 Pro or M5 Max) and 14-inch MacBook Pro (2023)
• Apple, tech specs: MacBook Neo, MacBook Air, MacBook Pro, and MacBook Pro (14-inch, 2023)
• Apple, Use a power adapter with your Mac
• Apple, View energy consumption in Activity Monitor on Mac
• Apple, Batteries: Maximizing Performance
• Our readings: ioreg -rn AppleSmartBattery, system_profiler SPPowerDataType and top on a 14-inch MacBook Pro (M2 Max), macOS 27.0.1, 20 October 2026, 13:41 to 14:06

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