Calculate the exact number of binary codes from bit depth, or the ideal ADC voltage step from bit depth and full input voltage span in volts or mV. Common bit depths are available as suggestions.
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Bit Resolution Formula
The bit resolution calculator uses two related formulas: one for the number of discrete levels from a bit depth, and one for the voltage step size of an ADC.
- L = total number of discrete levels or steps
- N = number of bits
- V_step = voltage represented by one ADC step
- V_ref = full ADC input voltage span (maximum minus minimum); equal to the reference voltage only when specified by the ADC transfer function
- N = number of ADC bits
In Bits → Levels mode, the calculator raises 2 to the number of bits. For example, 8 bits gives 28, or 256 possible levels. If the counting starts at 0, the maximum digital value is one less than the number of levels, so an 8-bit value ranges from 0 to 255.
In ADC Voltage Step mode, the calculator first finds the number of ADC steps with 2N, then divides the voltage range by that number. The result is the ideal quantization interval represented by one count, not a guarantee that a real ADC can distinguish every change of that size.
Common Bit Depths and Resolution Levels
| Bits | Levels | Digital range | Common use |
|---|---|---|---|
| 1-bit | 2 | 0 to 1 | On/off state |
| 8-bit | 256 | 0 to 255 | Basic color, older audio, simple data |
| 10-bit | 1,024 | 0 to 1,023 | Common microcontroller ADC |
| 12-bit | 4,096 | 0 to 4,095 | Higher-resolution sensor readings |
| 16-bit | 65,536 | 0 to 65,535 | CD audio, precision digital values |
| 24-bit | 16,777,216 | 0 to 16,777,215 | Studio audio, high-resolution ADCs |
Typical ADC Step Sizes
| ADC bits | Steps | Step size at 5 V range | Step size at 3.3 V range |
|---|---|---|---|
| 8-bit | 256 | 19.531 mV | 12.891 mV |
| 10-bit | 1,024 | 4.883 mV | 3.223 mV |
| 12-bit | 4,096 | 1.221 mV | 0.806 mV |
| 16-bit | 65,536 | 76.294 µV | 50.354 µV |
Bit Resolution Examples
Example 1: Find the number of levels for 12 bits
Use the levels formula:
A 12-bit value has 4,096 levels. If the range starts at 0, the digital values run from 0 to 4,095.
Example 2: Find the ADC voltage step for a 10-bit ADC with a 5 V range
First find the number of steps:
Then divide the voltage range by the number of steps:
The ADC step size is 0.0048828125 V, or about 4.883 mV per step.
Bit Resolution Calculator FAQ
What does bit resolution mean?
Bit resolution tells you how many discrete values a digital system can represent. Each added bit doubles the number of possible levels. For example, 8 bits gives 256 levels, while 9 bits gives 512 levels.
Why is the maximum value one less than the number of levels?
Digital values usually start counting at 0. If you have 256 total levels, the values are 0 through 255. That is still 256 possible values, but the highest code is 255.
Is ADC step size the same as real measurement accuracy?
No. ADC step size is the ideal voltage size of one count. Real accuracy also depends on noise, reference voltage accuracy, offset error, gain error, and the quality of the ADC circuit. A smaller step size means finer resolution, but it does not guarantee that the measurement is equally accurate.
