Signal to Noise Calculator


Select detector

QE %

Exposure time,s


Pixel size µm

Well capacity



Signal e-/eff.pixel

Total dark charge e-/eff.pixel

Single Pixel area µm2

Total noise e-/eff.pixel

CCD temp C°

S/N Ratio

Dark current e-/pixel/s

System gain e-/count

CCD readnoise e- rms

Expected CCD counts*

Spherical photon flux


Incident photons,ph/eff.pixel/s

Note: * The actual values may be 50-100 counts higher because of the Baseline Offset
Amplifier mode: Optimization of system performance for lowest noise or highest SNR.
Binning factor: The number of pixels to be combined on a CCD during binning.
Dark current: The charge accumulated within a well, in the absence of light.
Exposure time: The length of time that a CCD is accumulating charge.
Read noise: Unwanted signal or disturbance that is generated by the on-chip output amplifier
Signal-to-noise ratio: The ratio of the measured signal to the overall noise at that pixel.
Spherical photon flux: The number of photons intercepted by a sphere per unit time.
System gain: Relationship between the number of detected electrons and A/D units generated
Excess noise: The statistical nature of the EMCCDs results in excess noise between 1 to 1,4.
EM gain: Electrons are accelerated from pixel to pixel in the multiplication register.
Disclaimer: all numbers presented in this calculator should be used purely for reference and comparison purposes only. We do not assume any liability for their accuracy.