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QAM / PSK Bit Rate Calculator

Bits per symbol and raw bit rate for BPSK through 1024-QAM at your symbol rate — with approximate Eb/N0 requirements.

Raw bit rate
Bits per symbol
≈ Eb/N0 for BER 10⁻⁶
Occupied BW (α=0.25)
k = log₂M ; Rb = Rs·k ; BW ≈ Rs(1+α)
References: Proakis, Digital Communications (M-ary modulation, BER curves) · DVB-C / DOCSIS physical-layer specifications

Higher M packs more bits into the SAME bandwidth, paying in SNR: each step up the QAM ladder squeezes constellation points together, so noise flips symbols sooner. This is exactly why your WiFi falls back from 256-QAM near the router to QPSK in the garden — same channel, adaptive modulation tracking SNR. BPSK and QPSK share Eb/N0 because QPSK is two orthogonal BPSKs.

QAM Bit Rate Calculator computes bits per symbol and raw bit rate for PSK/QAM orders at a symbol rate — free, instant and private in your browser. Broadcast/cable techs and SDR experimenters decoding constellation choices 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 QAM / PSK Bit Rate Calculator

QAM Bit Rate Calculator computes bits per symbol and raw bit rate for PSK/QAM orders at a symbol rate using the standard engineering relation: k = log₂M; Rb = Rs·k; occupied BW ≈ Rs·(1+α). Worked live: 64-QAM at 6.95 MBd (DVB-C) moves 41.7 Mbit/s raw in ~8.7 MHz. 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 QAM / PSK Bit Rate Calculator

  1. 1Enter your values — the tool starts with realistic defaults for this exact use case, so the worked example is meaningful immediately.
  2. 2Read the live result and the worked-example panel, which substitutes your numbers into the formula step by step.
  3. 3Adjust any input to compare scenarios, then use Copy result or Copy permalink to share the calculation.

Why use QAM / PSK Bit Rate Calculator?

  • Implements the real formula — k = log₂M — with the substitution shown, not a black box
  • Built for broadcast/cable techs and SDR experimenters decoding constellation choices
  • 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 qam bit rate?+

Bits per symbol and raw bit rate for PSK/QAM orders at a symbol rate follows k = log₂M; Rb = Rs·k; occupied BW ≈ Rs·(1+α). For example, 64-QAM at 6.95 MBd (DVB-C) moves 41.7 Mbit/s raw in ~8.7 MHz. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.

Why doesn't everyone just use 1024-QAM everywhere?+

Each doubling of constellation density packs points ~3 dB closer, demanding that much more SNR for the same error rate. 1024-QAM needs ~27 dB — achievable on short coax, fantasy at a cell edge. That's why links adapt modulation to measured SNR in real time.

What's the α (roll-off) in the bandwidth estimate?+

The excess-bandwidth factor of the pulse-shaping (root-raised-cosine) filter: occupied spectrum = symbol rate × (1+α). α = 0.25 is common; smaller α squeezes more symbols into the band at the price of harder timing recovery and taller peak-to-average ratio.

Is the QAM Bit Rate 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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