Fragrance Blend Ratio Calculator

Understanding top, middle, and base notes

A simple way to think about fragrance structure is as a pyramid. Lighter materials sit at the top, while heavier, long-lasting materials form the base. Together, they create a scent that unfolds over time.

• Top notes are what you smell first. They are bright, volatile materials such as citrus, light herbs, and some aromatics. They evaporate quickly, usually within 15–30 minutes.
• Middle (heart) notes emerge as the top notes fade. Florals, many spices, and some fruits live here. They give the fragrance its main character and can last for several hours.
• Base notes are the longest-lasting materials, such as woods, resins, musks, ambers, and some balsams. They anchor the blend and influence how long the scent stays on skin, fabric, or blotters.

Perfumers adjust the ratio between these three groups to shift the mood of a blend. More top notes usually means a fresher, more fleeting impression. Heavier base ratios emphasize warmth, depth, and longevity.

How the calculator works (formulas and normalization)

The calculator assumes you are entering the total finished fragrance volume in milliliters, and the percentage of that volume you want to allocate to each note family. It then converts each percentage into a volume using a simple proportional formula:

For each note category (top, middle, base):

Where:

• V = volume of a given note group in milliliters
• P = percentage chosen for that note group
• V_total = total batch volume in milliliters

If your percentages for top, middle, and base do not add up to exactly 100, the tool automatically normalizes them so that their relative proportions stay the same while the total becomes 100%. For example, if you enter 20% top, 40% middle, and 20% base (total 80%), each value is divided by 80 and multiplied by 100, preserving the 1 : 2 : 1 relationship.

Step-by-step: using the Fragrance Blend Ratio Calculator

1. Decide the total volume you want to mix (for example, 10 ml for a test spray or 30 ml for a small bottle).
2. Enter this number into the Total Volume (ml) field.
3. Choose your Top Note (%), Middle Note (%), and Base Note (%) values. Aim for numbers that roughly add to 100. A common starting point is 20% top, 50% middle, 30% base.
4. Click the Calculate Blend button to generate exact milliliter amounts for each note group.
5. Record the results in your blending notebook or app, then break each group down into individual materials (for example, split your 3 ml of top notes among lemon, bergamot, and grapefruit).
6. After you mix your test batch, label the bottle with date, formula code, and key ingredients so you can evaluate it over several days.

Worked example: building a 30 ml everyday scent

Imagine you want to create a 30 ml everyday fragrance that feels bright at first but still has a soft, lasting base. You choose:

• Total volume: 30 ml
• Top notes: 20%
• Middle notes: 50%
• Base notes: 30%

Because the percentages add up to 100, no normalization is needed. The calculator applies the formula to each layer:

• Top notes: (20 ÷ 100) × 30 ml = 6 ml
• Middle notes: (50 ÷ 100) × 30 ml = 15 ml
• Base notes: (30 ÷ 100) × 30 ml = 9 ml

You might then decide to divide each group further:

• Top (6 ml): 3 ml bergamot, 2 ml sweet orange, 1 ml petitgrain
• Middle (15 ml): 8 ml lavender, 5 ml geranium, 2 ml cardamom
• Base (9 ml): 4 ml cedarwood, 3 ml vetiver, 2 ml benzoin

Once you blend and dilute appropriately in alcohol or a carrier, you can wear-test the fragrance and adjust the ratios in your next iteration.

Comparing common blend styles by ratio

Different fragrance styles often favor different balances of top, middle, and base notes. The table below gives example ratios you can plug into the calculator and adapt to your materials.

Use these as starting points only. Adjust the ratios and individual ingredients to match your personal taste and the strength of your materials.

Interpreting your results and next steps

The calculator output tells you how many milliliters of each note family to use, not which specific oils to choose. Stronger or more tenacious materials may need to be used in smaller amounts than lighter materials, even within the same group.

• If the fragrance feels too sharp or fleeting, consider reducing the top note percentage and increasing middle or base.
• If the scent is heavy or cloying, try lowering the base percentage and adding more middle or top notes.
• If your main theme (for example, rose or sandalwood) gets lost, shift some percentage into the group where that key material lives.

Keep detailed records of every blend so you can compare batches, refine your formulas, and eventually build a personal library of signature scents.

Assumptions, safety, and limitations

This tool is designed as a practical helper for hobbyists and small-scale makers. To use it responsibly, keep the following assumptions and limits in mind:

• Volume, not weight: Calculations are based on milliliters, assuming that fragrance components are simply additive in volume. In reality, different materials have different densities. For precision work, especially in professional perfumery, weighing ingredients in grams is preferred.
• Normalization behavior: When your percentages do not sum to 100, the calculator preserves the proportions you chose and scales them to a total of 100%. If you prefer exact percentages, adjust your inputs beforehand.
• No automatic safety checks: The tool does not validate inputs against IFRA guidelines, dermal maximums, or allergen restrictions. Always research safe usage levels for each essential oil, aroma chemical, or fragrance oil you use.
• Not a regulatory tool: Outputs are not suitable as-is for regulatory filings, labeling compliance, or professional cosmetic safety assessments.
• Patch testing is essential: Before wide use on skin, dilute your concentrate appropriately in alcohol or a carrier, then perform a small patch test and wait at least 24 hours.

For detailed safety information, consult reputable sources such as industry guidelines or a qualified cosmetic safety assessor, especially if you plan to sell your products.

Making the most of this calculator

To get ongoing value from this tool, treat it as the numerical backbone of your creative process. Use it to quickly explore new ratio ideas, keep batch sizes consistent, and document what works and what does not. Over time, you will start to recognize which structures match your style best, and you can reuse or adapt your favorite formulas with confidence.

Consider combining this calculator with a separate dilution or carrier-percentage calculator when you are ready to move from a concentrated perfume oil to finished sprays, roll-ons, or body products.