Hilberts Hotel Calculator

Hilbert's Hotel Calculator

Explore how an infinite hotel can always make room for more guests.

Last updated: June 2026 | By Patchworkr Team

Current Status
The hotel is full, but has infinitely many rooms.
Room Visualization (First 15 Rooms)
Room1G1
Room2G2
Room3G3
Room4G4
Room5G5
Room6G6
Room7G7
Room8G8
Room9G9
Room10G10
Room11G11
Room12G12
Room13G13
Room14G14
Room15G15

Green = vacant, Cyan = occupied (Guest #)

What it shows

The hotel demonstrates that countably infinite sets can be rearranged to make room for more guests.

Key idea

Move guests to room n + 1 for one new guest, or to room 2n for infinitely many new guests.

Worked Example

One new bus arrives with infinitely many guests.

1. Move guests from room n to room 2n

2. Free all odd-numbered rooms

Final answer: all guests accommodated

Frequently Asked Questions

Is this a real hotel?

No. It is a thought experiment about infinity.

Why does room 1 free up?

Because everyone moves from room n to room n + 1.

How do infinite guests fit?

By moving current guests to even-numbered rooms.

What does it prove?

It shows that countably infinite sets can be rearranged without changing size.

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