# Phage Lab Calculators

Six calculators for the phage lab, built for the bench in the Tarleton State University SEA-PHAGES lab and the [Virus Isolation Course](/teaching/virus-isolation). Each one shows every step of its arithmetic, so a result can be checked by hand and copied into a lab notebook, and each page states its formula and a fully worked example, from the lab's notebooks where they have one.

## The calculators

- [Titer calculator](/research/tools/titer): pfu/ml from a plaque count, the volume plated and the dilution, for a full plate titer or a spot titer.
- [Serial dilution planner](/research/tools/dilution): the tubes that take a lysate from its titer to a target concentration, with the volume to carry and the buffer for each.
- [Webbed plate calculator](/research/tools/webbed-plate): the lysate and dilution to plate for webbed plates from a lysate of known titer, and the lysate you get back from flooding them.
- [Lysate volume planner](/research/tools/lysate-volume): how much lysate a set of plates uses in all, and how to mix it with buffer to plate.
- [MOI calculator](/research/tools/moi): the multiplicity of infection from a titer, the volume added and a host cell count, and the share of cells infected.
- [Efficiency of plating calculator](/research/tools/eop): how well a phage plates on a test host against a reference host, from two titers or from plaque counts.

## Where the formulas come from

The titer, dilution and webbed plate formulas are the ones worked through question by question in [Lab Calculations and Common Questions](/teaching/virus-isolation/faq); the MOI and efficiency of plating calculators use the standard definitions, stated on their pages; and the lab's own settings (volumes plated, spot volumes, flood yields) come from the [Phage Isolation and Purification Protocol](/research/protocols/phage-isolation), which each calculator cites where it uses one.

## Titers from several plates

For titers from three or more plate counts, with trimmed means, confidence intervals and efficiency of plating, use Stephen Abedon's [Titering and EOP Calculator](https://titering.phage.org/). These calculators take one count at a time and show the arithmetic instead.