What is ADC resolution?

ADC resolution is the smallest voltage difference the converter can distinguish, equal to the full-scale range divided by 2^N, where N is the number of bits. A 12-bit ADC with a 3.3 V reference has a resolution of 3.3 / 4096 ≈ 0.806 mV per LSB.

How many quantization levels does an N-bit ADC have?

An N-bit ADC produces 2^N distinct output codes. For example, 8-bit = 256 levels, 12-bit = 4,096 levels, 16-bit = 65,536 levels, and 24-bit = 16,777,216 levels.

What is an LSB in an ADC?

LSB stands for Least Significant Bit. In the context of ADC voltage, 1 LSB is the voltage step size — the voltage change that increments the digital output code by exactly 1. It equals (V_max − V_min) / 2^N.

What is ADC dynamic range?

Dynamic range is the ratio in decibels between the largest and smallest measurable signals. For an ideal ADC it is approximately 6.02 × N + 1.76 dB (the SQNR formula). A 12-bit ADC achieves about 74 dB; a 16-bit ADC achieves about 98 dB.

Does a bipolar ADC have fewer positive levels?

The total number of levels is still 2^N regardless of the voltage range. For a bipolar input (e.g. −5 V to +5 V), the full-scale range is 10 V, and each LSB represents 10 / 2^N volts. Half the codes represent negative voltages and half represent positive voltages.

What limits real-world ADC resolution?

Noise, non-linearity, and input-referred offsets limit the effective number of bits (ENOB), which is typically 1–3 bits less than the nominal resolution. Effective resolution = (SINAD − 1.76) / 6.02 dB.

ADC Resolution Calculator

Enter ADC bit depth and reference voltage range to get voltage resolution, quantization levels, LSB size, and dynamic range.

ADC Parameters

Bit Depth (N)

bits

Typical: 8, 10, 12, 16, 24

V_min (lower reference)

Use 0 for unipolar (GND)

V_max (upper reference)

Common: 3.3, 5, 2.5, 1.8

Results

Quantization Levels

—

Voltage Resolution (LSB)

—

Full-Scale Range

—

Dynamic Range (SQNR)

—

Max Digital Code

—

1-bit (2 levels) — 32-bit (4G levels)

Bar shows bit depth relative to 32-bit maximum.

Formulas Used

Levels = 2^N

LSB = (V_max − V_min) / 2^N

Full-scale = V_max − V_min

SQNR ≈ 6.02 × N + 1.76 dB

Bit Depth Comparison (same voltage range)

Bits	Levels	LSB Voltage	SQNR (dB)

Summary

Enter ADC bit depth and reference voltage range to get voltage resolution, quantization levels, LSB size, and dynamic range.

How it works

Enter the ADC bit depth (4–32 bits) — e.g. 12 for a 12-bit ADC.
Enter the reference voltage range: either a single Vref (unipolar, 0 V to Vref) or a min and max voltage (bipolar).
Click Calculate to see quantization levels, LSB voltage, full-scale range, and dynamic range.
Use the comparison table to see how resolution scales from 8-bit to 24-bit for your voltage range.
Click Reset to clear all fields and start a new calculation.

Use cases

Verify the minimum detectable voltage change for a sensor ADC front-end.
Choose the correct ADC bit depth for a given measurement accuracy requirement.
Calculate the LSB size for microcontroller ADCs (STM32, PIC, Arduino) before firmware development.
Determine how many counts correspond to a known physical signal change.
Compare dynamic range of 12-bit vs 16-bit vs 24-bit ADCs for audio or instrumentation.
Validate ADC selection in a data acquisition system design review.

Frequently Asked Questions

Last updated: 2026-09-22 · Reviewed by Nham Vu