dB ↔ Ratio Converter
Decibels to voltage or power ratios and back — with the 10-vs-20 log distinction made explicit and memorable anchors.
The 10-vs-20 confusion exists because power ∝ V² — both formulas describe the SAME physical dB when impedances match. Decibels add where ratios multiply: a chain of +20, −3, +6 dB is simply +23 dB — the entire reason link budgets, audio gain staging and filter plots use logs.
dB Ratio Converter computes decibels ↔ voltage or power ratios, with the 10/20-log distinction explicit — free, instant and private in your browser. Audio, RF and measurement folk who keep getting 10-vs-20 backwards use it to skip the datasheet algebra: type your numbers, read the answer with the substituted formula shown step by step, and share an exact permalink of the calculation.
About dB ↔ Ratio Converter
dB Ratio Converter computes decibels ↔ voltage or power ratios, with the 10/20-log distinction explicit using the standard engineering relation: dB = 10·log₁₀(P2/P1) = 20·log₁₀(V2/V1). Worked live: a ×2 voltage ratio is +6.02 dB; a ×2 power ratio is +3.01 dB — same physics, different quantity. The result recalculates on every keystroke, the worked-example panel shows your numbers substituted into the formula, and the Copy permalink button encodes the inputs in the URL so a colleague opens exactly your calculation. Everything runs client-side — nothing you type leaves your device.
How to use dB ↔ Ratio Converter
- 1Enter your values — the tool starts with realistic defaults for this exact use case, so the worked example is meaningful immediately.
- 2Read the live result and the worked-example panel, which substitutes your numbers into the formula step by step.
- 3Adjust any input to compare scenarios, then use Copy result or Copy permalink to share the calculation.
Why use dB ↔ Ratio Converter?
- ✓Implements the real formula — dB = 10·log₁₀(P2/P1) = 20·log₁₀(V2/V1) — with the substitution shown, not a black box
- ✓Built for audio, RF and measurement folk who keep getting 10-vs-20 backwards
- ✓Copy result and permalink buttons — share the exact calculation in a README, forum answer or design review
- ✓100% free, no sign-up, runs entirely in your browser (works offline once loaded)
Frequently asked questions
How do you calculate db ratio?+
Decibels ↔ voltage or power ratios, with the 10/20-log distinction explicit follows dB = 10·log₁₀(P2/P1) = 20·log₁₀(V2/V1). For example, a ×2 voltage ratio is +6.02 dB; a ×2 power ratio is +3.01 dB — same physics, different quantity. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
Why 20·log for voltage but 10·log for power?+
Power goes as voltage squared (P = V²/Z), and the squared term becomes ×2 outside the log. Both formulas describe the SAME dB figure when impedances match — a 6 dB voltage doubling IS a 6 dB power quadrupling.
What are the dB anchors worth memorising?+
3 dB = ×2 power, 6 dB = ×2 voltage, 10 dB = ×10 power, 20 dB = ×10 voltage; 1 dB ≈ 12 % power. Chains add: +20 −3 +6 = +23 dB total. With these five facts you can sanity-check any link budget or gain structure mentally.
Is the dB Ratio Converter free and private?+
Yes — completely free with no sign-up or usage limits, and it runs entirely in your browser: the values you enter are never uploaded or stored on a server.
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