Helmholtz Resonator Calculator
Estimate lumped cavity/neck resonance with explicit entered total neck-end correction.
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Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Use uniform cavity compliance and a cylindrical neck air mass, adding your entered total end correction to the physical length.
f=c/(2π)√(neck area/(cavity volume×effective neck length))
Worked example
A 20 L cavity, 50 mm neck diameter and 140 mm effective neck length at 343 m/s give about 45.7141007 Hz.
Assumptions and input details
Lumped low-frequency approximation with one straight circular neck; end correction is supplied, not inferred from flanging. Neck/cavity modes, losses, speaker-driver interaction, airspeed and enclosure tuning validation are excluded.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
The 36 volume definitions distinguish US liquid, US dry and Imperial measures. Cups carry an explicit definition. Japanese shō is 2401/1331 L and a gō is one tenth of it; the explicitly labelled 180 mL rice cup is separate.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · UK Imperial definitions · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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