ToolJoltTools

Loudness-Matched A/B Calculator

Comparing two processing chains or masters? Enter both LUFS values to get the exact trim that makes the A/B fair — louder always sounds 'better' until you match level.

Trim the louder one by (dB)
Raw loudness gap (LU)

Even a 0.5 LU advantage makes a version sound subjectively better in blind tests — the 'louder wins' bias is the single biggest trap in mastering decisions. Always level-match before you A/B a plugin, a master, or a reference track. This is the arithmetic; do it before you trust your ears.

Rule / Formula

trim = −|A_LUFS − B_LUFS| applied to the louder version before auditioning
References: Katz, B., 'Mastering Audio' (level-matched monitoring); AES research on loudness bias

Comparing two processing chains or masters? Enter both LUFS values to get the exact trim that makes the A/B fair — louder always sounds 'better' until you match level.

About Loudness-Matched A/B Calculator

Comparing two processing chains or masters? Enter both LUFS values to get the exact trim that makes the A/B fair — louder always sounds 'better' until you match level. Even a 0.5 LU advantage makes a version sound subjectively better in blind tests — the 'louder wins' bias is the single biggest trap in mastering decisions. Always level-match before you A/B a plugin, a master, or a reference track. This is the arithmetic; do it before you trust your ears.

How to use Loudness-Matched A/B Calculator

  1. 1Enter your values into the fields in Loudness-Matched A/B Calculator.
  2. 2The result and any pass/fail verdict update instantly as you type — no button to press.
  3. 3Check the substituted formula and worked example to see exactly how the result was derived.
  4. 4Copy or note the result for your spec, delivery or planning.

Why use Loudness-Matched A/B Calculator?

  • Runs entirely in your browser with instant, private results — no data leaves your device.
  • Built on a published reference: Katz, B., 'Mastering Audio' (level-matched monitoring).
  • Shows the governing formula and a worked example, so you can trust and check every result.
  • 100% free with no sign-up, no watermark and no usage limits.
  • Works on any device — desktop, tablet or phone — and keeps working offline once loaded.

Frequently asked questions

What does Loudness-Matched A/B Calculator do?+

Comparing two processing chains or masters? Enter both LUFS values to get the exact trim that makes the A/B fair — louder always sounds 'better' until you match level. Even a 0.5 LU advantage makes a version sound subjectively better in blind tests — the 'louder wins' bias is the single biggest trap in mastering decisions.

Is my data private?+

Yes. Loudness-Matched A/B Calculator runs entirely in your browser — your inputs are never uploaded, stored or logged.

What standard or source is Loudness-Matched A/B Calculator based on?+

It follows Katz, B., 'Mastering Audio' (level-matched monitoring); AES research on loudness bias. Always confirm against the current official document, as specifications and rates can change.

What formula does it use?+

Loudness-Matched A/B Calculator uses: trim = −|A_LUFS − B_LUFS| applied to the louder version before auditioning. The tool shows this formula with your own numbers substituted so you can verify the result.

Is Loudness-Matched A/B Calculator free to use?+

Yes — it is completely free with no account, no sign-up and no usage limits. There is no watermark and no paywall.

Embed Loudness-Matched A/B Calculator on your website

Want Loudness-Matched A/B Calculatoron your own site? Paste this snippet into any HTML page — it's free, with no API key or sign-up. The tool loads in an iframe and keeps working exactly as it does here.

Embed code
<iframe src="https://tooljolt.com/tools/loudness-matched-ab-calculator" width="100%" height="640" style="border:1px solid #e5e7eb;border-radius:12px;max-width:680px" title="Loudness-Matched A/B Calculator — ToolJolt" loading="lazy"></iframe>

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