Gain-Bandwidth Product Calculator
Closed-loop bandwidth from GBW and noise gain — and how splitting gain across stages multiplies usable bandwidth.
Use NOISE gain, not signal gain: an inverting amp at signal gain −1 has noise gain 2, so it gets GBW/2. Aim for ≥10× margin between needed and available bandwidth or expect gain error and phase shift at the band edge. Two stages of ×4.5 comfortably beat one stage of ×20 on the same op-amp — that's the whole point.
Gain Bandwidth Calculator computes the closed-loop bandwidth a voltage-feedback op-amp delivers at your gain — free, instant and private in your browser. Anyone whose amplifier 'loses treble' or shows gain error at the band edge 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 Gain-Bandwidth Product Calculator
Gain Bandwidth Calculator computes the closed-loop bandwidth a voltage-feedback op-amp delivers at your gain using the standard engineering relation: BW = GBW/noise-gain; n-stage cascades shrink by √(2^(1/n)−1). Worked live: ×20 on a 3 MHz TL072 leaves 150 kHz; two ×4.5 stages instead leave ~430 kHz overall. 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 Gain-Bandwidth Product Calculator
- 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 Gain-Bandwidth Product Calculator?
- ✓Implements the real formula — BW = GBW/noise-gain — with the substitution shown, not a black box
- ✓Built for anyone whose amplifier 'loses treble' or shows gain error at the band edge
- ✓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 gain bandwidth?+
The closed-loop bandwidth a voltage-feedback op-amp delivers at your gain follows BW = GBW/noise-gain; n-stage cascades shrink by √(2^(1/n)−1). For example, ×20 on a 3 MHz TL072 leaves 150 kHz; two ×4.5 stages instead leave ~430 kHz overall. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
What is noise gain and why does it set bandwidth?+
It's the gain from the op-amp's input terminals to the output — 1 + Rf/Rg in BOTH standard topologies. The feedback loop runs out of loop gain at GBW/noise-gain regardless of your signal gain; an inverting unity amp (noise gain 2) gets only half the GBW.
How much bandwidth margin should I leave?+
10× between the needed and available bandwidth keeps gain error under ~0.5 % and phase shift small at your band edge. At exactly BW you're −3 dB and 45° — fine for casual filtering, ruinous for measurement chains.
Is the Gain Bandwidth Calculator 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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