What are the wattage differences between MagSafe 3 and USB C ports on the M2 Pro MacBook Pro 14"?

an iPad requires only about 20 Watts power. Its power adapter is inadequate for charging your Mac.

MacBook Pro M2 power adapter supplies up to 100 Watts power through USB-C Power delivery protocol, or up to 140 watts for fast charging through MagSafe-3.

if you want to drop one of the power adapters you carry, you can drop the iPad charger and charge your iPad off a cable from the Mac.

The only thing a power adapter using USB-C can not do for you is fast charge ABOVE the 100W level (an option on the 16-in MacBook Pro).

USB-C specs limit the charging rate on high-quality on USB-C cable to 100 W, and Apple decided to put it fast charging feature at higher power on its own MagSafe cable. There are USB-C cables with only 60W charging capability.

I don't think there are any measurable differences between USB-C charging rates and MagSafe charging rates other than fast charging.

Apple produced MagSafe with its release feature to keep from tripping over the cord from launching your macBook into the air and causing it to fall.

Most common USB-C cables are rated for 20V at 3A. That's the minimum standard and likely what Apple provides with USB-C cables for lower power Macs (like the MBA) or iPads.

The MagSafe 3 cables are really just USB-C power cables for Apple's proprietary connection. I would assume they can provide up to the maximum power that MagSafe 3 computers can use.

I've had no issue using a USB-C power adapter rated at 45W with a 5A (100W) rated USB-C cable on an 14" M1 MBP. It may not provide the fastest charging when depleted, but the charge level never sagged (i.e. it was always enough to provide enough power for operation without supplementary battery power).

Honestly I don't see why not just carry another USB-C cable. And using MagSafe 3 means that a USB-C port isn't tied up just for power input. But yeah the 2m MagSafe 3 cable is rather bulky and sometimes too long.

Not enough to be concerned about when using compatible Apple chargers. You can use ones rated at more or less than suggested but will likely get only marginally differential charging. The device draws power; the charger doesn't push power

Not sure if Apple is thinking of implementing the newer 48V USB-C standard.

The biggest problem I see is poor labeling of USB-C cables by current/voltage/speed ratings. I know most of what I have is 480 mbit/sec. But I’ve got some that are 5/10 mbit/sec like a USB-C to HDMI conversion cable and a USB-C to micro-B drive cable. I’d think some people have external drives with USB-C ports but then use whatever USB-C cables they have and find they’re slow.

You can see all that in System Report under Power. I’ve powered a 14” M1 MBP with just a 5W power source. Didn’t likely do much, but some computers won’t even accept it at all.