Emulsion Stability Calculator

It solves the HLB blend equation algebraically: since the target HLB is a weighted average of the two emulsifier HLBs, x = (requiredHLB - HLB_B) / (HLB_A - HLB_B) gives the weight fraction of emulsifier A directly. The remaining fraction (1 - x) becomes emulsifier B, and the calculator clamps the result between 0 and 1 so it never recommends a negative or over-100% blend.

The Stokes' Law formula in this calculator includes droplet radius squared, so creaming velocity scales with the square of droplet size, not linearly. Halving the radius through better homogenization reduces that squared term to one-quarter of its original value, which is why smaller droplets deliver disproportionately better shelf stability than the size reduction alone would suggest.

The calculator classifies your required HLB into three regimes: below 7 favors water-in-oil emulsions, above 8 favors oil-in-water, and 7-8 sits in a borderline zone where either emulsion type can form depending on other factors like phase ratio and processing. A borderline required HLB usually means small formulation changes, like a different emulsifier blend or oil phase ratio, can flip which emulsion type you actually get, so it's worth testing rather than assuming.

The creaming-velocity math assumes dilute, non-interacting spherical droplets, which is the classic Stokes' Law assumption, but real emulsions above roughly 20-30% dispersed phase or with flocculating droplets interact hydrodynamically and separate faster than isolated spheres would. Treat the calculated separation time as an optimistic best case and confirm actual shelf stability with an accelerated physical trial, especially at higher oil-phase percentages.