Room Mode Calculator

Free tool to find the standing waves of a rectangular room, with a frequency map. No sign-up

Enter the length, width and height of the room, in metres or feet, and the air temperature.
Choose the highest frequency to show (300 Hz is a common choice), or load an example room.
Show or hide axial, tangential and oblique modes.
Read the map: tall accent lines are axial modes, and highlighted bands mark axial modes within 5 Hz of each other.
Check the table for the exact frequencies, then download it as CSV or copy it as text.

Nothing is saved or uploaded: everything stays in your browser. Download or copy your results before closing the page. The calculation assumes an empty rectangular room with rigid walls, as every room mode calculator does: furniture, absorption and openings in a real room damp and shift these modes, so use the result as a map of where to look.

How do you calculate the room modes of a rectangular room?

Room modes are the frequencies at which a room resonates, set by its length, width and height. The lowest mode along one dimension is the speed of sound divided by twice that dimension: in a room 5.5 m long it is about 343 ÷ (2 × 5.5) ≈ 31 Hz. Combining the three dimensions gives every axial, tangential and oblique mode, and modes that fall close together can make some bass notes boom while others disappear. This free calculator lists all the modes up to the frequency you choose and shows them on a frequency map.

What are room modes?

When you play a bass note in a room, the sound bounces between the walls. At certain frequencies the reflections reinforce each other and form standing waves, so the bass is louder in some spots and weaker in others. These are room modes. Axial modes bounce between one pair of parallel surfaces and are the strongest. Tangential modes involve four surfaces and oblique modes all six, and both are weaker. In a small room the low modes are few and far apart, so the bass is uneven, and when two modes sit close together or on the same frequency (a square room is the extreme case) a few notes stand out. This tool tells you where to look; it does not measure your room.

Made by Luca Martone, sound designer and live sound engineer based in Turin.