Magic Meter

The Magic Meter is a green gauge that determines the amount of magic Link has to spare. First appearing in Zelda II: The Adventure of Link, it found its way into becoming an integral part of several Zelda adventures, including every 3-D platform with exception of Twilight Princess.

Use
The Magic Meter, as noted before, measures Link's ability to perform powers which can be done exclusively with Magic. Some of these powers include firing Ice and Fire Arrows, which are key in games such as Ocarina of Time and the Wind Waker. If Link can no longer execute such acts, it is likely due to the fact he has run out of Magic, and the Magic Meter will appear empty, indicating as such. Link can replenish his Magic with Magic Jars or Green Potions, and the Magic Meter will become partially, or entirely, filled.

Upgrades
In all games in which the Meter appears, there is an upgrade, usually from a Fairy, that grants Link the ability to use more Magic than before, in result extending the Magic Meter.
 *  A Link to the Past: If Link is to sprinkle Magic Powder on the strange statue near the Blacksmiths house, a bat-like creature will come and "curse" Link, cutting the Magic he uses by half.
 * Ocarina of Time: If he is to find it, a Great Fairy will increase the capacity of Link's Magic Meter.
 * Majora's Mask: By collecting the stray Fairies in the Snowhead Temple, an upgrade will be granted to Link extending his use of magic.
 * The Wind Waker: If Link is to save a Great Fairy from a Big Octo near Two-Eye Reef, she will double his use of Magic.