Room Mode Calculator
Find every standing wave in your room before you buy a single panel.
What it does
A working Excel/Google Sheets calculator that computes every axial, tangential, and oblique room mode in your space, flags clustering and gaps, and shows you exactly which bass frequencies your room is fighting you on.
Built for: Bedroom and home studio producers who want to understand their low end before buying treatment.
Features
- Enter length, width, height in meters or feet
- Calculates axial, tangential, and oblique modes up to 300 Hz
- Automatically flags modal clustering (reinforced frequency zones)
- Automatically flags large modal gaps
- Room ratio reference check
- Frequency chart included
- Fully editable spreadsheet formulas, not a locked PDF
What's included
smt-room-mode-calculator-v1.0-worksheet.xlsxsmt-room-mode-calculator-v1.0-guide.pdfsmt-room-mode-calculator-v1.0-example-room.jsonREADME.md
Compatibility
- Microsoft Excel (2016 or later) or Google Sheets
- Works on Windows, Mac, and in-browser via Google Sheets — no installation required
- PDF guide readable on any device
What this does not do
- Does not model modal decay/ringing over time — it calculates mode frequencies and flags clustering/gaps, not a full room impulse response
- Does not tell you which specific product to buy — see the Acoustic Treatment Planner for that
- Not a substitute for an on-site measurement — real rooms deviate somewhat from the ideal rectangular-room assumption this calculator uses
Frequently asked questions
Do I need Excel, or does Google Sheets work?
Both. The worksheet uses standard formulas that work identically in Excel 2016+ and Google Sheets — no macros or add-ins required.
What if my room isn't a perfect rectangle?
The calculator assumes a rectangular room, the standard starting assumption in room acoustics. If your room has an alcove, sloped ceiling, or open doorway, treat the numbers as a close approximation rather than an exact prediction.
Does this replace a real acoustic measurement?
No. It's a planning tool based on your room's dimensions. It will get you very close, but a measurement microphone and free software like REW is the only way to confirm what's actually happening in your specific room.