Purification Yield Calculator

Downstream purification of a biologic is a chain of sequential unit operations — clarification, capture chromatography, viral inactivation, two polishing chromatography steps, viral filtration, and ultrafiltration/diafiltration — and product is lost at every single step. Because each step's yield is applied to whatever material survived the step before it, overall yield is not an average of the seven percentages but their product: multiply all seven step recoveries together (each expressed as a fraction) to get the fraction of starting material that survives the entire train. This calculator applies that product to your starting mass to get final product mass, reports the mass lost as the difference, and also walks the running mass through the train step by step so you can see the cumulative amount remaining after capture, after polishing, and after the final UF/DF step — which is useful for spotting exactly where the biggest losses are occurring rather than only seeing the end result.

It also inverts the math to show how much starting material the same yield chain would require to reproduce your current starting mass as final product, illustrating how sensitive upstream feed requirements are to yield. The core assumption is that each step's yield is independent of the others and of scale — in reality, yields can shift with load, feedstock quality, and column aging, and this tool doesn't account for that variability, so treat the output as a deterministic planning estimate rather than a guarantee. A seemingly small drop in any one step (say 95% to 90%) compounds across six other multiplications and can meaningfully shrink the overall yield.