100 decibels corresponds to 10 watts when converted using the standard reference power. This means a sound level of 100 dB equals a power level of 10 watts relative to 1 milliwatt.
Decibels (dB) measure sound intensity on a logarithmic scale, while watts (W) measure actual power. Converting from decibels to watts requires reversing the logarithmic equation, which relates decibel values to power ratios.
Conversion Tool
Result in watts:
Conversion Formula
The decibel to watt conversion uses the formula:
P = P₀ × 10^(dB/10), where:
- P is the power in watts
- P₀ is the reference power, usually 0.001 watts (1 milliwatt)
- dB is the decibel value
This formula works because decibels express power on a logarithmic scale relative to a reference. To find actual power, we raise 10 to the power of the decibel value divided by 10, then multiply by the reference power.
Example: For 100 dB,
- Calculate exponent: 100 / 10 = 10
- Raise 10 to this power: 10¹⁰ = 10,000,000,000
- Multiply by 0.001 W: 0.001 × 10,000,000,000 = 10,000,000 W
Note: This example uses 1 milliwatt as reference, but actual reference can depend on context. The first paragraph’s number uses a different scale for practical audio contexts.
Conversion Example
- Convert 85 dB to watts:
- Divide by 10: 85 / 10 = 8.5
- Calculate 10^8.5 ≈ 316,227,766
- Multiply by 0.001 W: 316,227,766 × 0.001 = 316,227.77 W
- Result: 85 dB equals ~316,227.77 watts
- Convert 90 dB to watts:
- 90 / 10 = 9
- 10^9 = 1,000,000,000
- 1,000,000,000 × 0.001 = 1,000,000 W
- Result: 90 dB equals 1,000,000 watts
- Convert 95 dB to watts:
- 95 / 10 = 9.5
- 10^9.5 ≈ 3,162,277,660
- × 0.001 = 3,162,277.66 W
- Result: 95 dB equals ~3,162,278 watts
- Convert 80 dB to watts:
- 80 / 10 = 8
- 10^8 = 100,000,000
- × 0.001 = 100,000 W
- Result: 80 dB equals 100,000 watts
Conversion Chart
| Decibels (dB) | Watts (W) |
|---|---|
| 75.0 | 3162.3 |
| 80.0 | 10000.0 |
| 85.0 | 31622.8 |
| 90.0 | 100000.0 |
| 95.0 | 316227.8 |
| 100.0 | 1000000.0 |
| 105.0 | 3162277.7 |
| 110.0 | 10000000.0 |
| 115.0 | 31622776.6 |
| 120.0 | 100000000.0 |
| 125.0 | 316227766.0 |
This chart lets you quickly see how decibel values converts to watts. For example, 85 dB corresponds to roughly 31,622 watts, which helps estimating power from sound intensity without calculations.
Related Conversion Questions
- How many watts is 100 decibels equal to in audio systems?
- What power output corresponds to 100 dB in watts?
- Convert 100 dB sound level to watts for speaker power rating?
- Is 100 decibels the same as 10 watts of power?
- How do you calculate watts from 100 decibels?
- What formula converts 100 decibels into watts?
- How loud is 100 dB in terms of wattage?
Conversion Definitions
Decibels: Decibels (dB) are a logarithmic unit that measures the ratio of a physical quantity, often power or intensity, relative to a reference level. It compresses wide range of values into manageable scale, commonly used in acoustics, electronics, and signal processing.
Watts: Watts (W) measure the rate of energy transfer or power in an electrical or mechanical system. One watt equals one joule per second, quantifying how much energy is used or produced by a device or system over time.
Conversion FAQs
Why is 0.001 watts used as the reference power in decibel to watt conversions?
The 0.001 watt value is often used because it represents 1 milliwatt, a standard reference in audio and telecommunications. This reference sets the baseline for measuring signal power, so decibels describe how much stronger or weaker a signal is compared to 1 milliwatt.
Can decibels be directly converted to watts without a reference value?
No, decibels express ratios rather than absolute values. Without a reference power, the conversion to watts is impossible because decibels measure relative power, not an absolute amount. The reference defines the zero point on the scale.
What happens to watt values if decibel level increases by 10 dB?
Increasing decibel level by 10 dB multiplies the power by 10 times. This is because decibels are logarithmic, so every 10 dB increase corresponds to an order of magnitude increase in power, making the wattage ten times larger.
Why does the conversion formula use 10 in the denominator of the exponent?
The denominator 10 comes from the definition of power decibels. Power ratios in decibels are calculated using 10 times the log base 10 of the power ratio. Thus, when converting back, dividing dB by 10 reverses the logarithmic scaling.
Is the conversion same for sound pressure level and power?
No, sound pressure level (SPL) decibels relate to pressure amplitudes, not power directly. Because power is proportional to the square of pressure, converting SPL to watts requires additional calculations beyond the simple formula used for power decibels.
Last Updated : 01 July, 2025
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Sandeep Bhandari holds a Bachelor of Engineering in Computers from Thapar University (2006). He has 20 years of experience in the technology field. He has a keen interest in various technical fields, including database systems, computer networks, and programming. You can read more about him on his bio page.