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Ammonium Sulfate Cut Calculator

Grams of ammonium sulfate to weigh to raise a protein solution from one % saturation to another.

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(NH4)2SO4

About this calculator

Use this calculator in protein purification when you are at 30% SAS and want 60% in a known volume of supernatant.

The calculation is grams = V(mL) × 533 × (end − start) / (100 − 0.3 × end) / 1000. End must be at least start. Volume may be entered in millilitres (mL) or fluid ounces (fl oz); the calculator converts to millilitres. The result is reported in grams (or ounces/pounds if you selected an imperial volume).

This is a common bench formula. Temperature, protein load, and table-specific saturation charts are ignored.

Start % saturation: Current % saturation, 0–100. Fresh lysate is often 0; after a first cut maybe 30.

End % saturation: Target % saturation, at least the start value, for example 60.

Volume: Volume of protein solution you are salting, in mL or fl oz.

(NH4)2SO4: Solid ammonium sulfate to add, in grams.