How to Check Charging Power (Watts) on macOS

Want to know exactly how much power your MacBook is drawing from its charger? Here are several ways—ranging from command-line tools to a GUI app—that help you find out the charging wattage on macOS.

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🔧 Method 1: ioreg (CLI)

ioreg digs into the system’s battery info and pulls out wattage data.

ioreg -r -n AppleSmartBattery | grep -i "watts"

If that doesn’t show anything useful, try this extended version:

ioreg -w0 -l | grep -i "AppleSmartBattery" -A20 | grep -i "watts"

You may see output like:

"AppleRawAdapterDetails" = ({
  ...
  "Watts" = 60,
  ...
})

⚠️ Note: This is not the actual power being consumed in real time, but the maximum your charger offers during the USB PD negotiation. 60w is the maximum power your charger can offer.

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🧠 Method 2: system_profiler

system_profiler is macOS’s native way to show detailed hardware reports.

system_profiler SPPowerDataType

Look for:

AC Charger Information:
    Connected: Yes
    Wattage (W): 60

⚠️ Note: Again, this value reflects the charger’s rated output, not live power draw.

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🖥️ Method 3: GUI App — Powerflow

Powerflow shows the real-time charging wattage in a visual interface:

1. Install Powerflow:

   brew tap lzt1008/powerflow
   brew install --cask powerflow
   # Remove quarantine attribute to allow execution
   xattr -c '/Applications/Powerflow.app'
   # Open the app
   open /Applications/Powerflow.app'
   

2. The app displays live power draw, helping you understand charging behavior dynamically.

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✅ Summary

Method	Type	Shows Wattage	Notes
ioreg	CLI	✅	Advanced battery info
system_profiler	CLI	✅	Built-in, readable
Powerflow	GUI App	✅	Simple and visual, easy to use

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⚙️ What Is USB-PD Handshake?

When you plug in a USB-C charger, your Mac negotiates with it using the USB Power Delivery (USB-PD) protocol. This “handshake” determines:

• The maximum voltage and current the charger can supply
• The maximum power (watts) your Mac is allowed to draw

For example, if a charger advertises:

• Max Voltage = 20V
• Max Current = 3A Then negotiated power is 20V × 3A = 60W

But this DOES NOT mean your Mac is actually drawing 60W. Real-time power depends on:

• Battery level
• System load
• Thermal management

So, the ioreg and system_profiler commands show negotiated (theoretical) power, while apps like Powerflow display real-time consumption.