Bioreactor Sizing Calculator

Bioreactor sizing comes down to one core relationship: volumetric productivity (how much product a liter of culture makes per day) is the cell-specific productivity (qP, in picograms per cell per day) multiplied by how many cells are packed into that liter. This calculator converts qP and cell density into g/L/day, multiplies by run duration and harvest efficiency to get total product per liter for one complete run, then divides your target batch mass by that figure to solve for the working volume needed. Total vessel volume is working volume divided by a working-volume ratio (typically 0.65-0.80), reflecting that vessels always need headspace above the liquid for aeration and foam control, and the calculator then snaps that number up to the nearest standard commercial bioreactor size (from 1 L bench-scale up to 20,000 L).

Annual capacity assumes a fixed 5-day turnaround between runs for cleaning, sterilization, and setup, so runs per year is 365 divided by run duration plus that 5-day buffer, and annual output is just runs per year times per-run yield. The main levers worth understanding: raising cell density or specific productivity shrinks the required vessel size roughly proportionally, while a longer run duration trades more turnaround overhead for more product per run up to a point. This is a first-pass sizing estimate for process development and facility planning — it assumes steady-state exponential-style productivity across the whole run and doesn't model the ramp-up/decline productivity curve real fed-batch cultures actually show, nor does it account for scale-up losses in mixing, oxygen transfer, or shear that can appear only at larger vessel sizes.