Ingredient Concentration Mixer
Three DIY answers by weight: how much active for a target percentage, how to dilute a stronger stock down, and what concentration your batch actually is.
Weigh out
Mix
That’s a
Figures are by weight in grams. Weights are rounded down and a measured concentration is rounded up, so a batch never reads weaker than it is.
- Do not use this mixer to make acid (AHA/BHA), vitamin C or retinoid products at home. Their strength and pH decide whether they irritate or burn, and a kitchen scale cannot check either. Use a tested product and ask a dermatologist.
- Anything containing water (or aloe, hydrosols, tea) grows microbes unless it has an effective broad-spectrum preservative, and even then its shelf life cannot be known without lab testing. Keep it in the fridge, make small batches, and throw it out at any change in smell, color or texture.
- Patch test every batch before use. Stop at any redness, itching or stinging, and see a doctor or dermatologist if a reaction is severe or does not settle.
Get the percentage right
Half the craft of DIY skincare is hitting the right concentration. Too little active and a blend does nothing; too much and a gentle botanical becomes an irritant. The maths is straightforward once you work by weight rather than eyeballing drops and splashes — but it’s easy to fumble under a dim bathroom light with a scale in one hand.
This mixer covers the three questions that actually come up: weighing an active into a batch, diluting a stronger stock down to a gentler strength, and checking the concentration of something you’ve already made — all in grams, so a blend you like is one you can make again.
Frequently Asked Questions
How do I mix an ingredient to a target percentage?
Work by weight. For a target percentage of a finished batch, the active is simply the batch weight times the percentage divided by 100 — so a 10% active in a 50 g batch is 5 g of active and 45 g of base. The mixer does this for you and also handles the two related questions: diluting a stronger stock down, and reading back the concentration from the amounts you actually used.
What is C1·V1 = C2·V2?
It's the dilution rule: the amount of active stays the same before and after you add base, so (starting concentration × starting amount) equals (final concentration × final amount). To make a weaker batch from a stronger stock, the stock needed is the batch weight times the target percentage divided by the stock percentage. The tool applies this by weight and gives you the base to add.
Why weigh in grams instead of measuring by volume?
Weight is reproducible and doesn't depend on how a liquid is poured or how thick it is, which is why formulators work in grams. A small digital scale reading to a hundredth of a gram lets you hit a target concentration accurately and repeat a blend you liked.
Is home blending safe, and is this professional advice?
This is an educational calculator, not cosmetic-formulation, medical, or dermatological advice. Home blending can't replicate lab preservation, pH balancing, or stability testing, so DIY products spoil faster and carry real risks if made carelessly. Keep batches small and fresh, respect each ingredient's safe-use limits, patch test everything, and don't attempt to formulate prescription-strength actives at home.
Educational estimate only, not cosmetic-formulation, medical, or dermatological advice. Home blending can’t replicate lab preservation or stability testing. Respect each ingredient’s safe-use limits, keep batches small and fresh, and patch test everything.