Op-Amp Bandwidth Calculator
The bandwidth of an operational amplifier circuit is set by a simple trade-off: for a given part, the product of the closed-loop gain and the bandwidth is a constant called the gain-bandwidth product, or GBW. This calculator takes that gain-bandwidth product, read from the device datasheet, and the linear voltage gain your circuit is configured for, then divides the first by the second to give the closed-loop bandwidth in hertz. That bandwidth is the frequency at which the signal gain has dropped by 3 dB, the conventional edge of the usable passband. The relationship explains why a unity-gain buffer is fast while a high-gain stage built from the same amplifier is comparatively slow: asking for more gain spends more of the fixed product and leaves less bandwidth. Enter your own gain-bandwidth product and gain to size a stage, check that a part is fast enough for your signal, or split a required gain across cascaded stages to keep each one wide enough. Every figure here is computed deterministically from the constant gain-bandwidth relationship, shown in full below, with a worked example that reconciles exactly to the calculator so you can follow each step. The approximation holds for internally compensated voltage-feedback op-amps.
Closed-loop bandwidth equals the gain-bandwidth product divided by the closed-loop gain: Bandwidth = GBW / gain. A part with a 1,000,000 Hz gain-bandwidth product running at a gain of 100 has a bandwidth of 10,000.00 Hz. Higher gain means narrower bandwidth.
Op-amp bandwidth formula
Bandwidth = GBW / A
GBW = gain-bandwidth product (Hz)
A = closed-loop voltage gain (V/V)
Bandwidth = -3 dB closed-loop bandwidth (Hz)
For an internally compensated voltage-feedback amplifier the product of gain and bandwidth is conserved, so the usable bandwidth is the gain-bandwidth product divided by the gain.
Worked example
An amplifier has a gain-bandwidth product of 1,000,000 Hz and is wired for a closed-loop gain of 100.
- Take the gain-bandwidth product: 1,000,000 Hz
- Take the closed-loop gain: 100
- Divide: 1,000,000 / 100 = 10,000
- Closed-loop bandwidth = 10,000.00 Hz
The bandwidth is 10,000.00 Hz. These are the calculator's default inputs, so the result above matches the widget exactly.
Bandwidth at common gains (GBW = 1,000,000 Hz)
Bandwidth shrinks as the closed-loop gain rises, keeping the product constant.
| Gain (V/V) | Bandwidth (Hz) |
|---|---|
| 1 | 1,000,000.00 |
| 10 | 100,000.00 |
| 100 | 10,000.00 |
| 1,000 | 1,000.00 |
Method and measurement standards: US National Institute of Standards and Technology (NIST).
Op-amp bandwidth calculator: frequently asked questions
What is the gain-bandwidth product?
The gain-bandwidth product (GBW or GBP) is a constant for a given operational amplifier in a negative-feedback configuration: the product of the closed-loop gain and the resulting bandwidth stays roughly fixed. If you increase the gain, the bandwidth falls in proportion, and vice versa. Manufacturers publish the GBW in the device datasheet, usually in hertz or megahertz.
How do I find the closed-loop bandwidth?
Divide the gain-bandwidth product by the closed-loop gain. For example, an amplifier with a 1,000,000 Hz GBW running at a gain of 100 has a bandwidth of 1,000,000 divided by 100, which is 10,000 Hz. This is the frequency at which the gain has fallen by 3 dB from its low-frequency value.
Is the gain the voltage gain or the decibel gain?
Use the linear voltage gain, not the decibel figure. A gain of 100 means the output is 100 times the input. If your datasheet quotes 40 dB, convert it first: 40 dB equals a voltage gain of 10 raised to 40/20, which is 100. This calculator expects the linear gain.
Does this apply to all op-amp circuits?
The constant gain-bandwidth approximation holds well for internally compensated voltage-feedback op-amps in standard inverting and non-inverting configurations. Current-feedback amplifiers and uncompensated parts behave differently, so always confirm against the device datasheet for your specific part and configuration.
Why does higher gain reduce bandwidth?
Inside a voltage-feedback op-amp the open-loop gain rolls off with frequency at a fixed rate. Feedback trades some of that gain for stability and bandwidth, but the product of the two is conserved. Asking for more gain leaves less bandwidth, which is why high-gain stages are slower than unity-gain buffers built from the same part.
Official sources
- Measurement units, constants and electronics metrology: US National Institute of Standards and Technology (NIST). As at 25 June 2026.
Reviewed by the CalculatorHub team, edited by James Graham, 25 June 2026. See our methodology. This is general information, not financial, tax, legal or investment advice.