ADC resolution and noise calculator
Your 16-bit ADC behaves like 12 bits and you need to quote real resolution, not the datasheet headline. LSB size, ideal SNR, effective bits (ENOB), noise-free bits and how much oversampling actually buys.
Open the calculator in EM·LINKBelow is a worked example. The working calculator runs free in EM·LINK.
Worked example
Example inputs
Example result
Noise-free bits: 10. That is the conservative number to quote.
| Quantity | Value |
|---|---|
| LSB size | 50.4 µV |
| Noise | 4.96 LSB RMS |
| Ideal SNR | 98.08 dB |
| Noise-free bits | 10 |
| ENOB with 16× oversampling | 13.90 bits |
| Noise-free with 16× oversampling | 12 |
Peak-to-peak noise, taken as 6.6 × RMS: 1.65 mV.
Calculations run in your browser. Nothing is sent to us.
The working calculator is ADC Resolution & Noise in EM·LINK, our free browser tool. The button opens it directly.
How to read the result
Each 4x of oversampling adds one bit, but only if noise is at least 1 LSB. A perfectly quiet input gains nothing.
Noise-free bits is the conservative number you can put in a datasheet.
How this is calculated
Measured RMS noise is converted to LSBs. ENOB compares it with ideal quantisation noise, and noise-free bits use the peak-to-peak noise, taken as 6.6 times RMS.
The full derivation, step by step, is in the EM·LINK documentation.
Calculated per IEEE 1241 ADC terminology. These tools are an engineering aid, not a certification.
Next step
Logging these sensors across the plant? Embedos Edge takes analog and digital I/O.
Common questions
How do I calculate ENOB from noise?
Enter RMS noise. ENOB = N - log2(noise in LSB x sqrt(12)).
How many bits does oversampling add?
Half a bit per doubling, one bit per 4x.
ENOB or noise-free bits?
Noise-free bits is stricter and safer to quote.
Related tools
- 4 to 20 mA and 0 to 10 V loop scaling calculator, to turn counts into engineering units.
- Thermocouple type K and J, where microvolt signals make noise the limit.
- NTC thermistor, to see how many counts you get per degree.