dBFS ↔ dB SPL Converter
dBFS (decibels relative to Full Scale) measures a digital audio signal's level against the maximum value a system can represent. dB SPL (Sound Pressure Level) measures the physical acoustic pressure of a sound in the real world. The two scales are linked by a calibration reference: 0 dBFS = 94 dB SPL at 1 kHz, which corresponds to 1 pascal of sound pressure. This is a common convention, not a standard: the real mapping depends on your microphone's sensitivity and the gain of your recording chain, which the optional sensitivity correction lets you account for.
Converter
dBFS → dB SPL
dB SPL → dBFS
Formula: dB SPL = dBFS + 94 + offset | dBFS = dB SPL − 94 − offset | p = 20 µPa × 10^(dB SPL / 20)
Reference Points
| dBFS | dB SPL | Pressure (Pa) | Typical situation |
|---|---|---|---|
| 0 | 94 | 1.00 | Sound calibrator tone (1 Pa) |
| -34 | 60 | 0.0200 | Normal speech conversation, for a participant |
| -64 | 30 | 0.000632 | Whisper in the ear |
| -74 | 20 | 0.000200 | Leaves fluttering |
| -94 | 0 | 0.0000200 | Threshold of hearing |
When to Use This
Recording in the field with a calibrated microphone
When recording acoustic events in a real environment, your recorder's meters show dBFS. Knowing the microphone's sensitivity (usually specified in dBV/Pa) and applying the offset field above lets you read physical sound pressure directly from your digital meter — without post-processing.
Setting recording gain before a measurement session
Before starting a measurement session, you want to know: "if the source reaches 85 dB SPL, will I clip?" Use this converter to find the target dBFS headroom and set your input gain accordingly.
Post-processing: validating digital recordings against expected levels
After a recording session, you can cross-check measured dBFS peaks against known acoustic references (e.g., a sound calibrator at 94 dB SPL).
Integration into production DSP systems
In embedded audio systems, the dBFS ↔ dB SPL mapping is encoded as a constant offset in the DSP pipeline — applied at the input stage once the transducer sensitivity is characterized. Getting this constant right is critical for systems that report absolute levels (noise monitoring, occupational health, clinical devices). Need this calculation embedded in a production system? Contact us →
dBFS vs LUFS — What's the Difference?
dBFS is a unit for digital levels. Read on a peak meter, it gives the highest sample value at any given moment and tells you whether a signal is close to clipping.
LUFS (Loudness Units relative to Full Scale) measures perceived loudness integrated over time, weighted by how the human ear responds to different frequencies. Some published loudness targets:
| Platform | Target (LUFS) | True Peak Max (dBTP) |
|---|---|---|
| Spotify | −14 LUFS | −1 dBTP |
| Broadcast (EBU R128) | −23 LUFS | −1 dBTP |
| Apple Podcasts | −16 LUFS | −1 dBTP |
A signal at −20 dBFS peak may have very different LUFS values depending on its duration and spectral content. dBFS and LUFS serve complementary roles: use dBFS to avoid clipping, LUFS to ensure consistent loudness across platforms.
Related reading
−18 dBFS, −12 dBFS, −20 dBFS: Reference Levels, dBu and dBV
What the common dBFS targets mean, how they map to analog line level, and how to convert dBFS, dBu and dBV.
LUFS vs dBFS: Can You Convert LUFS to dB?
Why there is no single LUFS-to-dB formula, the one case where there is, and the loudness targets that matter.
dB SPL to Pascal: Formula, Table and Microphone Sensitivity
Convert decibels to sound pressure in pascals and back, with a reference table and mV/Pa to dBV/Pa conversion.