Convert Neper to Decibel
Live bidirectional calculator for Nepers (Np) and Decibels (dB) with verified formula and conversion charts.
Sound Level3 units
How the Calculation Works (Linear Scaling)
Since 1 Neper = 8.68589 Decibels, multiply the value in Nepers by 8.68589.
Neper to Decibel Conversion Table
Precomputed values for quick reference and printing.
| Neper | Decibel |
|---|---|
| 1 Np | 8.6859 dB |
| 2 Np | 17.3718 dB |
| 3 Np | 26.0577 dB |
| 4 Np | 34.7436 dB |
| 5 Np | 43.4294 dB |
| 6 Np | 52.1153 dB |
| 7 Np | 60.8012 dB |
| 8 Np | 69.4871 dB |
| 9 Np | 78.173 dB |
| 10 Np | 86.8589 dB |
| 15 Np | 130.2883 dB |
| 20 Np | 173.7178 dB |
| 25 Np | 217.1472 dB |
| 30 Np | 260.5767 dB |
| 40 Np | 347.4356 dB |
| 50 Np | 434.2945 dB |
| 75 Np | 651.4417 dB |
| 100 Np | 868.589 dB |
| Decibel | Neper |
|---|---|
| 1 dB | 0.1151 Np |
| 2 dB | 0.2303 Np |
| 3 dB | 0.3454 Np |
| 4 dB | 0.4605 Np |
| 5 dB | 0.5756 Np |
| 6 dB | 0.6908 Np |
| 7 dB | 0.8059 Np |
| 8 dB | 0.921 Np |
| 9 dB | 1.0362 Np |
| 10 dB | 1.1513 Np |
| 15 dB | 1.7269 Np |
| 20 dB | 2.3026 Np |
| 25 dB | 2.8782 Np |
| 30 dB | 3.4539 Np |
| 40 dB | 4.6052 Np |
| 50 dB | 5.7565 Np |
| 75 dB | 8.6347 Np |
| 100 dB | 11.5129 Np |
๐ Standard Benchmark Reference Values
International amplitude/field ratio natural logarithmic level ratio (2 / ln(10) B).
Exact RatioAbout Neper (Np)
A logarithmic level ratio unit based on natural logarithms (base e). Under the international amplitude/field ratio convention (ISO 80000-3), 1 Np = ln(e) = 2 / ln(10) B โ 0.8685889638 B โ 8.685889638 dB.
History: Named after John Napier (1550โ1617), the inventor of logarithms. Retained in international standards (IEC and ITU) for natural logarithmic attenuation.
Common Uses: Transmission line exponential decay equations, acoustic wave damping coefficient analysis, filter attenuation.
About Decibel (dB)
One tenth of a bel (1 dB = 0.1 B). In acoustic measurements, sound level L (dB) = 10 logโโ(P/Pโ) = 20 logโโ(p/pโ) for root-power quantities.
History: Introduced alongside the Bel as a more practical, convenient scale where 1 dB represents roughly the smallest difference in acoustic loudness perceptible to the human ear.
Common Uses: Acoustic sound pressure levels (SPL), audiometry hearing tests, audio amplifier gain, loudspeaker sensitivity ratings.
โ Frequently Asked Questions
How many Decibels are in 1 Neper?
There are exactly 8.68589 Decibels in 1 Neper (1 Np = 8.68589 dB).
What is the formula to convert Neper to Decibel?
The formula is: Decibel = Neper ร 8.68589. Since 1 Neper = 8.68589 Decibels, multiply the value in Nepers by 8.68589.
How do I convert 1 Np to dB manually?
To convert 1 Np to dB: apply the formula Decibel = Neper ร 8.68589. Substituting gives: 1 ร 8.68589 = 8.6859 dB.