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Desktop versionConsole versionMobile versionNintendo Switch versiontModLoader version
Desktop/Console/Mobile/Switch/tModLoader-Only Content: This information applies only to the Desktop, Console, Mobile, Switch, and tModLoader versions of Terraria.
Mechanical Ruler
  • Mechanical Ruler item sprite
Stack digit 1.png
TooltipCreates measurement lines on screen for block placement
RarityRarity level: 1
Research1 required

The Mechanical Ruler is an accessory purchased from the Mechanic for 1. While equipped, it draws a semi-transparent grid overlay on the screen, making individual block distances much clearer. This grid fades out when the player begins moving and returns once movement stops. The row and column of the block the mouse is hovering over are also highlighted in red, drawing a cross on the screen with the cursor at its center.

On the Old-gen console version Old-gen console version, this effect is caused by the Ruler.


  • Unlike most accessories, informational accessories such as the Mechanical Ruler do not need to be equipped in an accessory slot. The Mechanical Ruler may be carried in the player's inventory without loss of functionality, unless equipped to a social slot. Additionally, the info it provides will be shared with nearby players of the same team in multiplayer. Keep in mind modifiers will no longer apply to the player when not equipped.

The grid when the player is moving (above) and when the player is standing still (below).

  • Though it has very little utility in combat, the Mechanical Ruler can still receive a modifier and affect the player's stats.
  • Having the Mechanical Ruler equipped in a social accessory slot disables the item. Having it equipped in an active accessory slot enables the item's functionality even when the slot is set to be invisible.
  • The grid can then be toggled off and on in the upper left portion of the inventory screen, similarly to the Ruler, the Paint Sprayer and the Architect Gizmo Pack's paint sprayer part, as well as the Presserator, The Grand Design's Wire/Actuator visibility and its included ruler.
  • The game's "Tile Grid" setting creates a less obtrusive five block wide grid around the cursor, which can be useful if one finds that the Mechanical Ruler's overlay is too distracting.
  • This accessory can be equipped at the same time as the Ruler accessory for an even more complete block distance measuring overlay.