ADC Resolution Calculator

ADC Resolution Formula

Worked Example

A 12-bit ADC with a 3.3 V reference converting 1.65 V:

1. LSB = Vref ÷ 2ⁿ = 3.3 ÷ 4096 = 0.0008056640625 V
2. Code = floor(Vᵢₙ ÷ LSB) = floor(2048) = 2048
3. SNR = 6.02 × 12 + 1.76 = 74 dB

Output code for 1.65 V: 2048 = 0x800 = 100000000000₂ · Maximum quantisation error (rounding) ±½ LSB: 0.4028320313 mV · Ideal SNR 6.02n + 1.76: 74 dB · Dynamic range 20 log 2ⁿ: 72.24719896 dB · Step if defined as Vref/(2ⁿ − 1): 0.8058608059 mV

GATE tip

Each extra bit halves the LSB and adds about 6 dB of SNR. A successive-approximation ADC needs n clock cycles per conversion, while a flash ADC needs 2ⁿ − 1 comparators.

More Analog and Digital Electronics Calculators

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  Inverting −R_f/Rᵢₙ, non-inverting 1 + R_f/Rᵢₙ

  difference (R_f/Rᵢₙ)(V₂ − V₁); in-amp 1 + 2R/R_G; summing −(R_f/Rᵢₙ)ΣV

  Example: An inverting amplifier with Rᵢₙ = 10 kΩ, R_f = 100 kΩ and 0.2 V in: Voltage gain = -10.

  Open the op-amp gain calculator →

• 555 Timer Calculator

  f = 1/(ln 2 (R₁ + 2R₂)C) ≈ 1.44/((R₁ + 2R₂)C)

  duty = (R₁ + R₂)/(R₁ + 2R₂); monostable T = ln 3 × RC ≈ 1.1RC

  Example: An astable 555 with R₁ = 1 kΩ, R₂ = 10 kΩ and C = 10 µF: Frequency f = 6.86998 Hz.

  Open the 555 timer calculator →

• Decibel Calculator

  dB = 10 log₁₀(P₂/P₁) = 20 log₁₀(V₂/V₁)

  dBm = 10 log₁₀(P / 1 mW)

  Example: A power ratio of 100: Gain = 20 dB.

  Open the decibel calculator →

• LED Resistor Calculator

  R = (V_s − n V_f) / I_f

  n LEDs in series; resistor power P = (V_s − nV_f) I_f

  Example: One 2 V LED at 20 mA from a 5 V supply: Series resistor R = 150 Ω.

  Open the led resistor calculator →

Frequently asked questions

Sources

• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.