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dB Calculator
Convert a power or voltage ratio to decibels and back.
bolt Free Online Tool
⚡ Instant Results
📊 Clear Comparison
🔒 100% Free Tool
Power gain
Compare Your Options And Get Clear Answers
Convert a power or voltage ratio to decibels and back.
dB Estimator
Enter your numbers below for an instant estimate.
0
💡 Tip: dB = 10 log10(P2/P1) = 20 log10(V2/V1).
How It Works
Key concepts behind this calculator
1
Enter Values
Fill in each field with your own numbers.
2
Calculate
Results update as you change the inputs.
3
Review
Read the breakdown and the explanation.
4
Adjust
Change values to compare scenarios.
Quick Reference Guide
dB Quick Guide
Typical values for reference.
| Ratio | As power | Same ratio | As voltage |
|---|---|---|---|
| 2 | 3.01 dB | 2 | 6.02 dB |
| 10 | 10.00 dB | 10 | 20.00 dB |
| 100 | 20.00 dB | 100 | 40.00 dB |
| 1000 | 30.00 dB | 1000 | 60.00 dB |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Common Questions
dB Calculator FAQ
Answers to common questions about this calculator.
A logarithmic unit comparing two values.
Power uses 10, voltage and sound pressure use 20.
About double the power.
About half the voltage.