Convert Decibels to Millibels

Convert Decibels (dB) to Millibels (mB) instantly and accurately.

Conversion Formula

mB = dB × 100

About Decibels

The decibel (dB) is the universal unit of sound level and signal level in acoustics, audio engineering, and telecommunications. Named in honour of Alexander Graham Bell (1847–1922), it was adopted by Bell Telephone Laboratories and CCITT in the 1920s–1930s. Sound pressure level: L_p = 20 × log₁₀(p/p₀), where p₀ = 20 µPa in air (ISO 1683). Key SPL reference points: 0 dB SPL = threshold of human hearing; 60 dB SPL = normal conversation at 1 m; 85 dB SPL = NIOSH 8-hour occupational limit; 120 dB SPL = pain threshold; 194 dB SPL = theoretical maximum undistorted plane wave in air at 1 atm. In digital audio (AES17, IEC 61606), 0 dBFS = maximum digital full-scale level. In RF engineering, 0 dBm = 1 mW; Wi-Fi signal strength ranges from −30 dBm (excellent) to −90 dBm (unusable). 1 dB = 0.1 B = ln(10)/20 Np ≈ 0.11513 Np.

About Millibels

The millibel (mB) is one-thousandth of a bel (1 mB = 10⁻³ B = 0.01 dB), the finest routine subdivision of the bel family in widespread practical use. The AES17-2015 standard for digital audio converter measurement requires frequency response flatness within ±0.01 dB (±1 mB) across 10 Hz–20 kHz for a reference-quality interface. Audiometer calibration (IEC 60645-1, ANSI S3.6) specifies attenuator step accuracy to ±0.1 dB (10 mB) for research-grade psychoacoustic instruments. Modern audio codec chips (ESS Sabre ES9038PRO) specify passband ripple to 0.01 dB = 1 mB. In broadcast loudness metering (EBU R128, ITU-R BS.1770), integrated loudness is calculated at 0.1 LU = 10 mB resolution. IEC 61672-1 Class 1 sound level meters achieve frequency response flatness within ±0.7 dB (70 mB) from 31.5 Hz to 8 kHz. 1 mB = 0.001 B = 0.01 dB ≈ 1.151 × 10⁻³ Np.

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