The Health Meter is an on-screen indicator of how much health the fighters have left. It appears in every Super Smash Bros. game, and is shown at the bottom of the screen, except in Super Smash Bros. for Nintendo 3DS, which displays the Health Meter on the touch screen.
In the games, the Health Meter acts a damage counter which displays the amount of damage that a particular character has taken as a percentage. The higher the percentage goes, the more damage the character has taken. As the character takes more damage, the color of the percentage gradually changes from white to a dark red, with yellow being a middle gradient introduced in Super Smash Bros. for Nintendo 3DS / Wii U, and the character simultaneously becomes easier for the opponents to KO them. The highest amount of damage a character can possibly take is 999%. Food, Heart Containers, Fairy Bottles and Maxim Tomatoes can help reduce the amount of damage that a character has taken. In all games, the Health Meter appears for each character that participates in a match. Starting in Super Smash Bros. for Nintendo 3DS / Wii U, characters with 100% of damage or higher begins to emit smoke.
Aside from displaying the damage of a character, the Health Meter also displays some other information. In Super Smash Bros. Brawl, the name of the character is always shown beneath the damage percentage, and an icon of the character's face is to the left of the damage percentage (at the top in the earlier games). The symbol signifying the series that the character comes from is displayed behind the damage percentage. In Stock matches, up to five circles (represented as character heads in Super Smash Bros., Super Smash Bros. Melee, and Super Smash Bros. for Nintendo 3DS / Wii U) appears above the damage percentage representing the amount of Stock that the character currently has left. One of the circles disappears for every time that the character is flung off the screen. When the character has no circles left, they get defeated and cannot participate for the remainder of the match. In Time matches, the number of KOs is shown above the damage percentage. A point is earned or lost if the character KOs an opponent or gets KO'd, respectively. In Coin Matches, the number of coins in hand is displayed.