Skip to content
Soap Math
How to use Color Math FDA colorant calculator

How to Use Color Math

FDA Colorant Calculator — Mix, Match & Batch

Color Math is a calculator built for soap and cosmetic makers who work with pigments, dyes, and mineral colorants. It helps you manually blend FDA-approved colorants, automatically match a target color using available pigments, or batch-match multiple colors at once. Every blend shows FDA compliance indicators so you know exactly where your colorants are safe to use. It has three tabs, each designed for a different workflow.

The Three Tabs

1. Color Mix

Manually select FDA-approved colorants from the dropdown, set each one's percentage, and see a live color preview of your blend. The total percentage tracker helps you hit 100%, and an FDA compliance summary shows whether your blend is safe for eyes, lips, general use, or external use only. Generate a printable results page when you're done.

2. Color Match

Enter a target color (hex code or RGB values), select which colorants you have available, and the calculator automatically finds the best blend percentages to match your target. Results include a match accuracy percentage, a detailed color analysis panel (color family, lightness, saturation, warmth, skin tone detection), pigment guidance constraints, and substitute colorant suggestions when ideal pigments are missing.

3. Bulk Match

Enter up to 20 hex codes (one per line), select your available colorants, and calculate matches for all target colors at once. Results display in a comparison table showing each target, the matched color, accuracy, and the percentage of each colorant used — great for planning product lines with consistent colorant inventory.

How to Use: Color Mix

Use this when you already know which colorants you want and need to visualize the blend.

  1. Step 1: Select a colorant from the FDA-approved dropdown and tap "Add." Each colorant shows compliance badges (👁️ eye, 💄 lips, 🧴 external) in the dropdown.
  2. Step 2: Set each colorant's percentage. The total should add up to 100% for accurate color prediction — the percentage tracker turns green when it does.
  3. Step 3: Watch the result color swatch and hex code update live as you change percentages.
  4. Step 4: Review the FDA Compliance Summary that appears below — it checks your entire blend for eye, lip, general, and external use approval.
  5. Step 5: Tap "Generate Results" to open a printable formula sheet with your blend, result color, FDA compliance, and space for notes.

Example: Add Ultramarine Blue (40%), Titanium Dioxide (50%), and Iron Oxide Black (10%). The preview shows a slate blue, and the compliance summary confirms it's approved for eye area and external use, but not for lips/general use (Ultramarine Blue is "No" for general use).

How to Use: Color Match

Use this when you have a target color and want the calculator to figure out the best blend for you.

  1. Step 1: Enter your target color using either a hex code (e.g., #FF5733) or RGB values (0-255 for each channel). A color swatch previews your target.
  2. Step 2: Add the colorants you have on hand from the dropdown. The calculator only uses colorants you select — the more you add, the better the match accuracy.
  3. Step 3: Tap "Calculate Best Match." The algorithm tests thousands of blend combinations and refines the best one to maximize accuracy.
  4. Step 4: Review the Color Analysis panel — it shows your target's color family, lightness, saturation, warmth index, and any skin-tone detection with undertone classification.
  5. Step 5: Check the "Best Match Formula" with exact percentages for each colorant, and the match accuracy score (95%+ is excellent).
  6. Step 6: If accuracy is below 95%, the "How to Improve This Match" panel appears with specific colorants to add to your available list. It scores each suggestion based on how much it would close the gap between your current match and the target.
  7. Step 7: Check the analysis panels — "Substitute Colorants in Use" shows which swaps were made when ideal pigments are missing, and "Missing Colorants (No Substitute)" flags pigments with no available alternative.

Example: You want a dusty rose (#BC8F8F). Enter the hex, add Iron Oxide Red, Titanium Dioxide, Iron Oxide Yellow, and Mica. The calculator finds a blend like TiO2 65%, Red Oxide 20%, Mica 10%, Yellow Oxide 5% with 96% accuracy. The analysis shows "red" family, 63% lightness, warm undertone.

How to Use: Bulk Match

Use this when you need to match multiple target colors at once using the same set of colorants.

  1. Step 1: Enter up to 20 hex codes in the text area, one per line (e.g., #FF0000, #00FF00, #FFD700).
  2. Step 2: Select your available colorants from the dropdown — these are the pigments the calculator can use for every match.
  3. Step 3: Tap "Calculate All Matches." The calculator processes each target color and finds the best blend for each one.
  4. Step 4: Review the results table — each row shows the target color, matched color, accuracy percentage, and the exact percentage of each colorant used.
  5. Step 5: Tap "Print Results" to print the comparison table for reference.

Example: Planning a lip balm line with 8 shades. Paste all 8 hex codes, add your 5 available colorants (approved for lip use), and get every formula at once. The table makes it easy to compare how much of each colorant you'll need across your entire product range.

FDA Compliance Indicators

Every colorant and blend in Color Math shows three FDA approval indicators:

👁️Eye Area: Whether the colorant or blend is FDA-approved for use around the eyes (eye shadow, eyeliner, mascara). Some colorants have conditional approval ("Limited") with specific product restrictions.
💄Lips/General Use: Whether it's approved for lipstick, lip balm, and general cosmetic application. Some colorants have concentration limits (e.g., D&C Orange No. 5 is limited to 5% in lipsticks).
🧴External Use: Whether it's approved for externally applied cosmetics like soap, lotion, and body products.

How blend compliance works: When you have multiple colorants in a blend, the compliance summary shows the most restrictive rating. If even one colorant isn't eye-safe, the entire blend is marked as not eye-safe. Special limitations (like concentration caps) are called out separately.

Color Analysis & Pigment Guidance (Color Match)

When you run Color Match, the calculator shows a detailed analysis of your target color:

Color Family: Identifies whether your target is red, blue, green, orange, purple, yellow, magenta, neutral (gray/black/white), etc.
Lightness & Saturation: How light/dark and how vivid the target color is. High saturation means vivid color; low saturation means muted or pastel.
Warmth Index: Positive values mean warm (more red/yellow), negative means cool (more blue). Zero is neutral.
Skin Tone Detection: If your target falls in skin-tone range, the calculator identifies the undertone (warm, cool, or neutral) — useful for foundation and concealer matching.
Pigment Guidance: The algorithm sets minimum and maximum constraints for key pigments based on the analysis — e.g., "Titanium dioxide: min 60% — Very light color requires high white base" — and shows the reasoning behind each constraint.

Common Use Cases

Matching a color for soap: Use Color Match — enter your desired hex code, add your available mineral colorants (iron oxides, ultramarines, titanium dioxide), and get exact percentages for your test batch.
Experimenting with blends: Use Color Mix — pick colorants you're curious about, adjust ratios freely, and see the resulting color update in real time.
Planning a product line: Use Bulk Match — paste all your target shade hex codes, select the colorants you want to use across the line, and get every formula at once for side-by-side comparison.
Checking compliance for lip products: Use Color Mix to build your blend, then check the FDA compliance summary — it flags any colorant that's not approved for lip use and shows concentration limits.

Tips for Working with Colorants

  • Always do a small test batch — screen colors differ from how pigments look in your actual base medium.
  • Iron oxides and ultramarines are stable in cold process soap; many FD&C dyes will morph or fade in high pH.
  • Start with less colorant than you think you need — you can always add more, but you cannot remove it.
  • Mix pigments into a small amount of oil before adding to your batch to avoid clumping and speckling.
  • In Color Match, adding more available colorants gives the algorithm more options and typically improves accuracy.
  • Check the "Missing Colorants" panel in Color Match — it tells you exactly which pigments to purchase to improve your results.

Frequently Asked Questions

Related Resources

Ready to work with colorants?

← Back to Resources