P-Meter

The Power Meter, sometimes shortened to P-Meter, is a type of meter first seen in Super Mario Bros. 3. For it to fill up, Mario or Luigi must keep running without stopping. Once the Power Meter is fully charged and the "P" icon starts flashing, Mario can run at full speed. If Mario is Raccoon Mario or Tanooki Mario, he will also have the ability to fly if the Power Meter is full. However, the Power Meter will always empty itself after a while, regardless of Mario's current state; if Mario is flying, he stops and descends; otherwise, he slows down. If Mario uses a P-Wing before entering a level, the Power Meter is full for the rest of the stage or until Mario takes damage, grabs a non-flight-based power-up, or loses a life, meaning Mario can fly for an unlimited amount of time.

In the Super Mario All-Stars and Game Boy Advance versions of Super Mario Bros. 3, instead of its original black and white appearance, the Power Meter is colored orange when filled up, and the "P" icon flashes red. In the latter port, the Power Meter stays full if Mario keeps running, meaning that Mario can extend his flight time by landing and taking off again while the "P" icon flashes. It also beeps in a lower pitch if Mario isn't in Raccoon or Tanooki form. It can be halved by the Cyan Switch, and Boost Blocks make it charge faster.

The Power Meter returns in New Super Mario Bros. 2, only appearing when Mario is Raccoon Mario (or White Raccoon Mario), with a few visual changes. The "P" icon is replaced by a red-outlined P-Wing icon (which flashes golden), the meter itself is colored red when filled up, and the meter visually empties as Mario flies, unlike in Super Mario Bros. 3, where the meter looks full until Mario stops flying. Aesthetics aside, the Power Meter works as it did in Super Mario Advance 4, though the White Raccoon form makes it charge faster.

The Power Meter returns in Super Mario Maker and Super Mario Maker for Nintendo 3DS, but it only appears in the Super Mario Bros. 3 theme, working as it did in that game.

In Super Smash Bros. for Nintendo 3DS / Wii U, Little Mac has a Power Meter (based on the arcade Punch-Out!! games), which builds up as he attacks or gets damaged. When fully charged, his neutral special move becomes an uppercut that possibly can K.O. opponents, even at lower percentages.