AudioCalcs
Stereo Width Calculator — Mid/Side Level from Width
Calculate Mid/Side levels from stereo width percentage.
How We Calculate This
Mid/Side Encoding
Mid = (Left + Right) / 2
Side = (Left − Right) / 2
Width Control
Side Level = Width% / 100 (relative to Mid at unity)
At 100% width, Side equals its original level. At 0%, Side is muted (mono). At 200%, Side is doubled.
Mono Compatibility
Mono Energy = Mid² / (Mid² + Side²) × 100%
When a stereo signal is summed to mono (L + R), the Side component cancels and only the Mid survives. Acoustic energy is proportional to amplitude squared (Parseval), so the fraction of energy retained in mono is the squared-amplitude ratio above — not the linear ratio. At 100% width Mid = Side, so 50% of the energy is retained; at 200% width the Side is doubled, so only 1²/(1² + 2²) = 20% is retained.
Frequently Asked Questions
Mid/Side (M/S) processing splits a stereo signal into two components: Mid (the centre/mono content, L+R) and Side (the stereo difference, L-R). By adjusting these independently, you can control stereo width, enhance the centre image, or widen the sides without affecting the centre.
0% = mono (no side signal). 100% = original stereo width (side signal at unity). 200% = double width (side signal doubled, +6 dB). Values above 100% exaggerate the stereo image but can cause phase issues and reduce mono compatibility.
When a stereo signal is summed to mono, the Side component cancels out completely. Wider mixes (more Side content) lose more energy in mono. A 200% width mix could lose significant content when summed to mono. Check your mix in mono regularly.
Bass and kick: 0-30% (keep centred for mono compatibility). Vocals: 50-100%. Synth pads: 100-150%. Room mics/ambience: 100-200%. Master bus: 100-120% maximum. Always check mono compatibility after width adjustments.
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Last updated: February 2026
All calculations are estimates based on standard formulas. Always verify results for critical applications.