How to Check Mac Charging Wattage and Power Draw

To check wattage through the graphical interface, hold Option and click the Apple menu, then select System Information. Navigate to Power in the sidebar. Under AC Charger Information, you will see the Wattage field, which shows the maximum wattage your connected charger can deliver.

The same Power section lists battery amperage and voltage under the Battery Information heading. These values update in real time and tell you the current draw rate. The wattage tells you how fast your Mac is charging or, when on battery, how much power it is drawing.

For a Terminal approach, open Terminal and run system_profiler SPPowerDataType. This command outputs all power data in one block, including charger wattage, battery charge remaining, cycle count, voltage, and amperage. It is the same data shown in System Information but accessible from the command line.

Apple ships each MacBook with a charger rated for its power requirements. The MacBook Air with M1, M2, M3, or M4 chips includes a 30W or 35W adapter. The 14-inch MacBook Pro ships with a 67W or 70W adapter. The 16-inch MacBook Pro comes with a 96W, 140W, or higher wattage adapter depending on the chip configuration.

Using a lower wattage charger than the one included is safe. The Mac will charge more slowly, and under heavy load it may draw power from the battery even while plugged in. Using a higher wattage charger is also safe because the Mac only draws what it needs. A 140W charger connected to a MacBook Air will deliver only 30W.

Both MagSafe and USB-C support variable wattage through USB Power Delivery negotiation. The charger and Mac communicate to agree on the appropriate voltage and current. This means any compatible USB-C charger will work, though charging speed depends on the charger's maximum wattage.

When your Mac is connected to a charger, the wattage reading reflects the total power being delivered. Some of that power goes to running the Mac (CPU, GPU, display, and other components) and the remainder goes to charging the battery. If the Mac is consuming 25W and the charger delivers 67W, the remaining 42W goes toward charging.

When running on battery, the wattage reading shows how much power the Mac is pulling from the battery. Higher CPU or GPU workloads increase power draw significantly. An idle MacBook Air typically draws around 3 to 8 watts. Heavy workloads on a MacBook Pro can push power draw to 30 to 60 watts or more.

Understanding this distinction helps you interpret the numbers you see in System Information or monitoring tools. A high wattage while plugged in is normal and means the battery is charging quickly. A high wattage on battery means your Mac is working hard and battery life will be shorter.

Lithium-ion batteries degrade faster when exposed to heat. High power draw from demanding workloads raises the internal temperature of the Mac, and that heat transfers to the battery. Over time, sustained high temperatures cause irreversible chemical changes in the battery cells, reducing maximum capacity.

Charging at high wattage pushes more current through the battery, which generates more heat than slow charging. While fast charging is convenient, frequent high wattage charging sessions can contribute to slightly faster degradation compared to using a lower wattage charger.

macOS includes Optimized Battery Charging, which learns your daily routine and limits charging to 80% until shortly before you need a full charge. This reduces the time the battery spends at maximum capacity, where stress on the cells is highest.

Monitoring power draw helps you understand which workflows are hardest on your battery. If you notice consistently high wattage during certain tasks, you can adjust your habits to reduce thermal stress and extend battery lifespan.

MoniThor calculates live wattage and updates it continuously, with a refresh interval you can configure to 1, 2, or 5 seconds. This lets you see power draw change in real time as you open apps, start heavy workloads, or plug in a charger.

The battery section in MoniThor displays the current charge percentage, health percentage, cycle count, voltage, time remaining estimate, and charging state. You can see at a glance whether your Mac is charging or discharging and at what rate.

This real time visibility makes it easy to correlate power draw with specific tasks. If you notice a spike in wattage, you can identify the responsible application and decide whether to close it or adjust your workflow. Visit the Features page for a complete list of monitored metrics, or return to the home page for an overview of MoniThor.

Lower screen brightness. The display is the single largest power consumer on a MacBook. Reducing brightness by even 20% to 30% makes a noticeable difference in battery runtime and overall power draw.

Close GPU intensive apps when on battery. Applications that use the GPU heavily (video editors, 3D rendering tools, some browsers with hardware acceleration) increase power draw substantially. Closing them when you do not need them saves watts.

Use Safari instead of Chrome.Safari is optimized for macOS energy efficiency. Apple's own testing consistently shows Safari consuming less energy than third party browsers, especially for video playback and general browsing.

Enable Low Power Mode.Open System Settings > Battery and turn on Low Power Mode. This reduces system performance slightly but lowers power consumption across the board, extending battery life during lighter workloads.

Check Activity Monitor's Energy tab. Open Activity Monitor and click the Energy tab to see which apps have the highest Energy Impact. This helps you identify and close the biggest power consumers.

Reduce external displays when unplugged. Each connected display increases GPU workload and power draw. If you are running on battery, disconnecting external monitors can significantly reduce power consumption.

MoniThor complements these strategies by showing real time power draw in the menu bar, so you can immediately see the impact of each change. Learn more about battery monitoring in the Mac Battery Health guide, the Mac Battery Cycle Count guide, or explore the Mac Performance Monitor guide.