Clean, offline decibel conversions for audio/RF/acoustics. Change any field — everything updates instantly.
Assumes sine wave for Vrms↔Vpp (Vpp = 2·√2·Vrms). dBm is power-referenced (1 mW) and needs impedance to relate to volts.
Reference for SPL is 20 µPa: SPL = 20·log10(p/20µPa).
dB = 20·log10(V₂/V₁) = 10·log10(P₂/P₁) and P ratio = (V ratio)² (same impedance).
The decibel (dB) is a logarithmic unit used to express a ratio — commonly sound level (acoustics), signal level (audio/RF), or gain/attenuation. Voltage-based quantities use 20·log10(); power-based quantities use 10·log10(). Because it’s logarithmic, equal steps in dB correspond to multiplicative changes in voltage or power.
dBV references 1.000 Vrms. dBu references 0.775 Vrms (historically 1 mW into 600 Ω). Both are voltage-based: dBV = 20·log10(V/1V), dBu = 20·log10(V/0.775V).
dBm is a power reference to 1 mW. To convert between dBm and volts you need load impedance Z, because P = V²/Z. We provide 50/75/600 Ω presets and a custom field.
For a sine wave: Vpp = 2·√2·Vrms ≈ 2.828·Vrms. This app assumes sine to keep conversions deterministic.
dBFS (digital full scale) needs a calibration: the converter must know the device’s full-scale Vrms. Without that, dBFS can’t map to volts absolutely.
No. Weightings are measurement filters, not constant offsets. This converter uses the unweighted SPL definition with a 20 µPa reference.