Ranges

Guild Wars ranges are measured in in-game units. These units are often referred to as "gwinches" because they correspond to a real-world inch (source).

Here is a list of important distances:

• 144 Touch skills and melee auto-attack
• 166 Adjacent
• 240 Nearby for a handful of skills, including Aftershock, Dragon's Stomp, Earthquake, Flame Burst, Frozen Burst, Gust, Healing Ribbon, Incendiary Bonds, Liquid Flame, Phoenix, Rodgort's Invocation, Shatterstone, Stone Sheath, Winds of Disenchantment, and Whirlwind
• 252 Nearby for most skills
• 322 In the Area
• 324 "Together as one!"
• 360 HoS/Viper's range. Range is actually random between around 298 and 322 in open space, but can go up to 360 to cross terrain. If you cast on yourself or without a target, the direction is random but the range increases to up to around 800.
• 700 Chain aggro
• 1000 Earshot (for some skills)
• 1004 Spear/shortbow range with level elevation
• 1012 Earshot (for some skills) and Aggro range
• 1248 Casting/wanding range (unaffected by elevation)
• 1273 Recurve/hornbow range with level elevation
• 1498 Longbow/flatbow range with level elevation
• 2500 Passive spirit effect radius
• 5000 Radar, Recall

• Bond range is also 5000, but bonds can be maintained at a greater distance for up to 5 seconds. If the bonder and target are further than 5000 gwinches apart for more than 5 seconds, the bonds will end.