Dimensional Box

Dimensional Box
Box sprite
Mechanic type	Gameplay Mechanic

(This is a box.)
(You can put an item inside or take an item out.)
(The same box will appear later, so don't worry about coming back.)
(Sincerely, a box lover.)

A sign introducing the dimensional box to the protagonist in Snowdin Forest

A Dimensional Box can be used to store items, as the protagonist can only carry up to 8 items at a time in their Inventory. There are a few physical boxes before Alphys upgrades the protagonist's Cell Phone in the Neutral and True Pacifist routes. After the protagonist's phone is upgraded, two Dimensional Boxes (one of which is the normal box) appears in the phone list and can be used to move items around. Dimensional Boxes A and B can be accessed at any point in the game via Cell Phone, whereas the physical Dimensional Boxes only contains items from Dimensional Box A. If the protagonist is on the Genocide Route, Alphys does not show up to upgrade the protagonist's phone; however, three additional boxes are placed to compensate for this.

Items cannot be directly swapped between a box and the protagonist's inventory, only deposited and withdrawn. If all boxes and the player's inventory are full, and the player wants to exchange an inventory item for a box item, they must consume or drop an item first to make the switch possible. The protagonist cannot use the dimensional boxes if they do not have any items in the inventory nor in the box.

Each box can store up to 10 items, so in the True Pacifist and Neutral routes, the protagonist can be in possession of a total of 30 items (2 from equipped items). While in the Genocide Route, the protagonist can have a total of 20 items.

The first time the protagonist opens a box (the first of which is located in Snowdin Forest), it contains a Tough Glove, which can be taken free of charge.

Box Locations

Snowdin Forest

• On the road just after Sans and Papyrus are met for the first time, with a box lover's sign next to it.

Snowdin

• In front of the Snowed Inn and Shop.

Waterfall

• On the left side of the falling rocks room, with a box hater's sign next to it.
• Next to the telescope prank Sans puts up.
• Outside of Gerson's shop.
• In Temmie Village outside of the Tem Shop.

MTT Resort (Genocide Route)

• At the bottom right corner of the lobby.

New Home (Genocide Route)

• Right outside the house, in front of the right window.
• In the Last Corridor beside the SAVE Point.

Gallery

In Snowdin Forest

In Snowdin Town

In the Waterfall Rock room

Near the Telescope

In Temmie Village

Near Gerson's shop

In the MTT Resort, only found on the Genocide Route

In New Home, only found on the Genocide Route

In the Last Corridor, only found on the Genocide Route

Trivia

• If the protagonist tries to use the dimensional boxes in the Artifact Room the message "The box is aclog with the hair of a dog." is displayed, implying that the Annoying Dog is to blame. The protagonist is not able to use the boxes until they leave the room or deploy the dog. This is done to prevent the protagonist from obtaining the Legendary Artifact.
• A quote from the box lover is included in the trailer for the collector's edition release of Undertale for PlayStation 4 and PlayStation Vita.
• Puppydough Icecream, an unused healing item, is too long a name to display correctly in a dimensional box.
• In the game files, the box is referred to as sansbox. Whether this implies the boxes were designed, constructed, or placed by Sans, or that its apparent teleportation derives from Sans, is unclear.