ADC Resolution Calculator

Calculate LSB size, levels, max code, and convert Voltage ↔ Code for an ideal ADC using any reference range.

How to Use

  1. Choose your bit depth (e.g., 10, 12, 16).
  2. Set Vref Low and Vref High (range can be 0–3.3V, 0–5V, or offset like 1–2V).
  3. Enter either a Voltage or an ADC Code to convert (or both).
  4. Open Show Work for formulas and intermediate steps.
ADC Snapshot
Ideal math: step size, codes, and quantization limits.
Levels
—
Max Code
—
LSB
—
±0.5 LSB
—
Range
—
Mode
Auto

Tip: Use Vref Low for offset ADC ranges (example: 1.000V to 2.000V sensors).

Inputs
Deterministic math; no uploads; results update instantly.
Common: 8, 10, 12, 14, 16, 18, 24
Clamp keeps code in [0 .. 2^N − 1].
Usually 0V. Use for offset ranges if needed.
Examples: 3.3V, 5.0V, 2.048V reference.
For Voltage → Code conversion.
Accepts 1234 or 0x4D2 (if Hex/Auto).
Show Work (step-by-step)
—
Work uses an ideal ADC with codes 0 .. (2^N − 1) and step size LSB = (VrefHi − VrefLo) / 2^N.

Reference

  • Levels: Levels = 2^N
  • Max code: Max = 2^N − 1
  • Range: Range = VrefHi − VrefLo
  • LSB (step size): LSB = Range / 2^N
  • Voltage from code: V = VrefLo + Code × LSB
  • Code from voltage (ideal): Code = (Vin − VrefLo) / LSB (then round/floor/ceil)
  • Quantization error: approximately ±0.5 LSB

Notes: Real ADCs also have offset/gain error, INL/DNL, noise, and reference tolerance. This tool covers the ideal math.

FAQ

What does “LSB” mean?

LSB is the smallest input voltage change that moves the ADC output by 1 code (for an ideal ADC).

Why is it 2^N levels but 2^N − 1 max code?

Because code starts at 0. With 2^N total codes, the last one is 2^N − 1.

Which rounding should I use for Voltage → Code?

Round is common for estimating the nearest code. Floor matches “truncate” style conversions. Ceil is useful when you need a guaranteed non-underestimate.

Can I use an offset range (not starting at 0V)?

Yes—set Vref Low and Vref High to your actual input span.

Tool Info

Last updated:

Updates may include extra formatting options, export helpers, and edge-case handling.