Poisson assay toolkit

Poisson Distribution Calculator

Explore event distributions, droplet loading, observed occupancy, and co-encapsulation with explicit units and reproducible results.

Poisson distribution

Calculate a probability mass function and evaluate a probability statement.

Mean event count per interval or droplet.
Optional; large values are rendered around the meaningful mass.
A number from 0 to 1.
Convert occupancy probabilities into expected counts.
The Poisson model assumes independent events at a constant average rate. For droplet assays, λ is the expected number of cells or molecules per droplet.

Theoretical λ in droplets

Estimate loading from droplet size and concentration, or solve for a target positive rate.

0% is valid; 100% has no finite λ.
Diameter mode assumes spherical droplets; volume mode uses the entered volume directly.
Canonical volume: pL (1 pL = 10⁻¹² L). λ = cells/mL × volume(pL) / 1,000,000,000.

Observed λ from occupancy

Use a measured fraction or enter positive and total droplet counts.

Choose the unit explicitly; 100% has no finite λ.
If p is the positive fraction, P(empty) = 1 − p = e−λ.
Observed λ = −ln(1 − p). Count mode also reports a 95% Wilson interval transformed through this relation.

Co-encapsulation probability

View independent population loading as a joint distribution and four-state overview.

Conditional co-encapsulation

Interpret the result within the positive subpopulation you care about.

All-droplet probabilities

Assumptions: homogeneous concentration, fixed droplet volume, random independent partitioning, and independent Poisson processes. The joint heatmap includes explicit row, column, and corner tail mass.

How to use this calculator

Enter values with spaces, thin spaces, apostrophes, or clear decimal commas. Results retain full-precision raw values in exports.