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Calcimator

Emulsion Formulation Calculator

Oil and water phase percentages with emulsifier HLB.

About this calculator

This calculator splits an emulsion batch into oil, water, and emulsifier weights, then solves a two-emulsifier HLB blend using the weighted-average method William C. Griffin published in 1949 (extended in his 1954 paper on non-ionic surfactants) — the formulation-science technique still used today to pick the ratio of a high-HLB and low-HLB emulsifier pair that hits a target HLB. Oil Phase grams equals batch size times oil phase percentage divided by one hundred (line 29). Total emulsifier grams uses the emulsifier percentage the same way (line 30). Water Phase grams is whatever remains after subtracting oil and emulsifier from batch size, so raising oil or emulsifier percentage automatically shrinks the aqueous phase (line 31). High-HLB fraction equals required HLB minus low-HLB value divided by the span between high and low emulsifiers, clamped between zero and one (lines 35-38).

High and low emulsifier grams split total emulsifier by that fraction (lines 40-41). Achieved Blend HLB is the weighted average of the two emulsifier HLB values at that split (line 44). Oil-to-Water Ratio divides oil phase grams by water phase grams (line 47). Required HLB and individual emulsifier HLB values do not change oil or water phase grams. Emulsifier percentage does not change Oil Phase grams either — only batch size and oil phase percentage set that mass — but it does change Water Phase grams, since Water Phase is simply the batch balance left over after both oil and emulsifier weights are subtracted (line 31).

Inputs

oz
%
%

Results

Oil phase (g)

25

Water phase (g)

70

Water phase (%)70
Total emulsifier (g)5
High-HLB emulsifier (g)2.57
Low-HLB emulsifier (g)2.43
High-HLB fraction (%)51.46
Achieved blend HLB10
Oil:water ratio0.36

Figures current as of 1949. Source: Griffin WC. Classification of Surface-Active Agents by 'HLB'. Journal of the Society of Cosmetic Chemists. 1949;1:311-326. Method extended in Griffin WC. Calculation of HLB Values of Non-Ionic Surfactants. J Soc Cosmet Chem. 1954;5:249-256.

How to Use This Calculator
  1. Enter the batch size and oil phase percentage for your formula.
  2. Set the required HLB for your oil blend, then enter the HLB values of your high-HLB and low-HLB emulsifiers.
  3. Input the total emulsifier usage level as a percentage of the batch.
  4. Review the emulsifier split between the high- and low-HLB components, the achieved blend HLB, and the resulting water phase and oil:water ratio.
  5. Use these ratios as starting points for bench-scale trials.

How the result changes with Batch size (g)

Batch size (g)Oil phase (g)Water phase (g)
5012.535
7518.7552.5
15037.5105
25062.5175

What each input means

Batch size (g)
Total weight of the emulsion batch in grams.
Oil phase (%)
Oil phase as a percentage of total batch. Typical range 15-40% for lotions, 40-70% for creams.
Required HLB
Target HLB for your oil phase. Mineral oil ~10-12, beeswax ~9, coconut oil ~8, stearic acid ~15.
Emulsifier (%)
Total emulsifier as a percentage of batch. Typically 3-8% for stable emulsions.
High-HLB emulsifier
HLB value of your hydrophilic emulsifier (e.g., Polysorbate 60 = 14.9, Polysorbate 80 = 15).
Low-HLB emulsifier
HLB value of your lipophilic emulsifier (e.g., Span 60 = 4.7, Span 80 = 4.3).

What each result means

Oil phase (g)
Weight of oil phase ingredients.
Water phase (g)
Weight of water phase (balance after oil + emulsifier).
Water phase (%)
Water phase as percentage of total batch.
Total emulsifier (g)
Total weight of emulsifier blend.
High-HLB emulsifier (g)
Grams of the hydrophilic emulsifier needed.
Low-HLB emulsifier (g)
Grams of the lipophilic emulsifier needed.
High-HLB fraction (%)
Percentage of emulsifier blend that is the high-HLB component.
Achieved blend HLB
Actual HLB of your emulsifier blend (should match required HLB).
Oil:water ratio
Oil to water weight ratio for the emulsion.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Batch size (g) = 100, Oil phase (%) = 25, Required HLB = 10, Emulsifier (%) = 5 = 6 input(s) provided
  2. Calculate Oil phase
    Oil phase = batchSize * (oilPhasePct / 100)
    25 = 25
  3. Calculate Water phase
    Water phase = Math
    70 = 70
  4. Calculate Water phase
    Water phase = Math
    70 = 70
  5. Calculate Total emulsifier
    Total emulsifier = batchSize * (emulsifierPct / 100)
    5 = 5

Figures and sources

Engine last updated . Checked against 3 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.

Frequently Asked Questions

Why can Water Phase grams hit zero even though I entered a normal oil percentage?

Water Phase is the batch balance after oil and emulsifier weights are subtracted (line 31). If oil phase percentage plus emulsifier percentage reaches or exceeds one hundred, the aqueous remainder clamps to zero (line 51). Check that your emulsifier level and oil phase together leave room for the water phase before scaling to production.

How does Required HLB change the split between high- and low-HLB emulsifiers?

High-HLB fraction equals required HLB minus the low emulsifier's HLB, divided by the difference between high and low HLB values, then clamped to zero through one (lines 35-38) — this is Griffin's 1949 weighted-average HLB method, the same technique formulators have used for over 70 years to blend two emulsifiers to a target HLB. A higher required HLB pushes more of the emulsifier blend toward the hydrophilic component without changing total emulsifier grams (lines 40-41).

Will Achieved Blend HLB always exactly match my Required HLB input?

When high and low HLB values differ, the fraction is chosen so the weighted average equals required HLB (lines 38, 44). If high and low HLB are identical, the engine defaults the fraction to one half (lines 36-37), and achieved HLB equals that shared value rather than a tunable target.

Does Batch Size change Oil-to-Water Ratio or only the gram weights?

Oil-to-Water Ratio divides oil phase grams by water phase grams (line 47). Because both phases scale linearly with batch size when percentages are fixed, the ratio stays constant while absolute gram weights grow proportionally with batch size (lines 29-31).

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