Shannon Channel Capacity Calculator
The theoretical bit-rate ceiling from bandwidth and SNR, beside the Nyquist M-level limit — with spectral efficiency.
Shannon's limit is unbeatable but approachable — modern LDPC/turbo codes get within ~1 dB of it, which is why 5G and DOCSIS feel like magic. The formula shows the lever trade: +3 dB SNR ≈ +1 bit/s/Hz, but doubling BANDWIDTH doubles capacity outright — spectrum is worth more than power. Nothing exceeds C; claims otherwise are compression, not capacity.
Shannon Capacity Calculator computes the theoretical bit-rate ceiling of a channel from bandwidth and SNR — free, instant and private in your browser. Comms students and engineers sanity-checking link claims 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 Shannon Channel Capacity Calculator
Shannon Capacity Calculator computes the theoretical bit-rate ceiling of a channel from bandwidth and SNR using the standard engineering relation: C = B·log₂(1 + SNR); the Nyquist line R = 2B·log₂M for M levels. Worked live: 1 MHz at 30 dB SNR caps at ~9.97 Mbit/s — and no coding scheme ever beats it. 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 Shannon Channel Capacity 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 Shannon Channel Capacity Calculator?
- ✓Implements the real formula — C = B·log₂(1 + SNR) — with the substitution shown, not a black box
- ✓Built for comms students and engineers sanity-checking link claims
- ✓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 shannon capacity?+
The theoretical bit-rate ceiling of a channel from bandwidth and SNR follows C = B·log₂(1 + SNR); the Nyquist line R = 2B·log₂M for M levels. For example, 1 MHz at 30 dB SNR caps at ~9.97 Mbit/s — and no coding scheme ever beats it. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
How close do real systems get to the Shannon limit?+
Astonishingly close: LDPC and turbo codes operate within ~1 dB of capacity — that's 5G, WiFi 6, DOCSIS and deep-space links. The historical gap was 6–9 dB; closing it is one of engineering's quiet triumphs. A '56k' modem already sat essentially AT its phone-line ceiling.
More power or more bandwidth — which buys more capacity?+
Bandwidth, linearly: doubling B doubles C outright, while doubling power adds only ~1 bit/s/Hz once SNR is decent (log term). That asymmetry is why spectrum auctions cost billions and why ultra-wideband and bonding exist.
Is the Shannon Capacity 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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