How to Calculate Fragrance Load

Getting fragrance load right is one of the biggest game changers in candle making and soap making. It's the difference between products that fill a room with scent and ones that barely register. It's the line between professional results and frustrating failures.

Too little fragrance and your product smells weak or nonexistent. Too much and you risk sweating, poor burn performance, separation, or failing safety guidelines - not to mention wasting expensive fragrance oil.

Here's how to calculate fragrance load properly, so you get strong scent throw without compromising quality or your budget.

What Is Fragrance Load?

Fragrance load is the percentage of fragrance oil used in relation to your base material - whether that's wax, soap base, diffuser base, or another medium.

Critical point: It's always calculated by weight, not volume.

Simple Example:

If your wax batch weighs 1000g and you add 80g of fragrance oil, your fragrance load is:

80g ÷ 1000g = 0.08 or 8% fragrance load

That's it. The formula is straightforward, but knowing which percentage to use and why is where the real skill comes in.

Step-by-Step: How to Calculate Fragrance Load

Step 1: Weigh Your Base Material

Start by weighing the total amount of your base- wax, soap, base or whatever medium you're working with. This is your foundation number.

Example:
You're making a candle batch using 1000g of soy wax.

Step 2: Choose Your Fragrance Percentage

Different products and base materials have different recommended maximum loads. This isn't arbitrary - it's based on how much fragrance oil the base can properly absorb and hold without causing performance issues.

Typical Fragrance Load Ranges:

• Candles: 6–10%
• Wax melts: 8–12%
• Cold process soap: 3–6% (often IFRA restricted)
• Melt and pour soap: 2–3%
• Reed diffusers: 15–30% (varies by base)
• Room sprays: 1-5%

These are starting ranges, not absolute rules. Always check:

1. The recommended maximum load for your specific base (ie. our Room Linen Spray recommended load is 1%)
2. The IFRA guidelines for your chosen fragrance oil
3. Any specific restrictions for the product category you're making

Step 3: Calculate the Fragrance Oil Amount

Once you know your base weight and desired percentage, the calculation is simple.

Formula:
Fragrance oil (g) = Base weight (g) × Fragrance load (%)

Example 1 (8% fragrance load):
1000g wax × 0.08 = 80g fragrance oil

Example 2 (6% fragrance load):
1000g wax × 0.06 = 60g fragrance oil

Example 3 (10% fragrance load):
500g wax × 0.10 = 50g fragrance oil

See how the math works? Once you've done it a few times, it becomes second nature.

Quick Reference: Common Fragrance Load Calculations

Here's a handy table for the most common batch sizes and loads. Save this for quick reference when you're working:

Pro tip: Keep a printed copy of this table in your workspace or save it on your phone for easy access during production.

The Truth About Maximum Load

Here's something many beginners don't realize: just because your wax can hold 10% fragrance doesn't mean you should use 10%.

More fragrance does NOT equal better performance.

In fact, you'll often get:

• Better burn performance (cleaner burn, less sooting)
• Less sweating or oil seepage (especially in warmer conditions)
• Cleaner, smoother candle tops
• Stronger hot throw (counterintuitive but true)

...at a lower load like 6–8%, depending on the wax type and specific fragrance oil.

Why Does This Happen?

When you overload wax with fragrance, it can't properly bind with all the oil. The excess sits on the surface or pools at the bottom, leading to sweating, poor burn quality, and wasted fragrance that never gets released into the air.

Additionally, some fragrance oils are formulated to throw powerfully at lower concentrations. Using these at maximum load is literally throwing money away.

The sweet spot varies by:

• Wax type (soy, paraffin, coconut, blends)
• Fragrance oil strength and composition
• Container size and wick choice
• Ambient temperature and humidity

This is why testing at multiple loads is so important.

Why Measuring by Weight Matters (Not Volume)

Here's a mistake that trips up many beginners: measuring fragrance oil by volume (ml, teaspoons, cups) instead of weight.

The problem: Fragrance oils have different densities. Some are thicker and heavier, others are lighter and more fluid.

10ml of one fragrance oil might weigh 9g, while 10ml of another weighs 11g. If you measure by volume, your fragrance load will be inconsistent from batch to batch and fragrance to fragrance.

The solution: Always measure by weight using a digital scale.

• Weigh your wax in grams
• Weigh your fragrance oil in grams
• Calculate your percentage based on these weights

This ensures:

• Consistency between batches
• Accurate scaling when you increase production
• Reliable results every single time
• Proper compliance with IFRA limits

Invest in a good digital scale that measures to 0.1g accuracy. It's one of the most important tools in your workspace.

Test Before You Scale (The Smart Maker's Approach)

Never assume one fragrance will behave like another, even if they're from the same supplier or smell similar. Different oils have wildly different performance characteristics.

Some fragrance oils:

• Throw powerfully at 6% but sweat at 8%
• Need 9–10% to reach full scent strength
• Cause discoloration or acceleration in soap
• Affect burn quality or wick performance
• Develop differently during cure time

The smartest approach:

Make test batches of the same fragrance at two different loads (for example, 6% and 8%) and compare:

• For candles: Cold throw, hot throw, burn quality, appearance
• For soap: Scent retention, discoloration, acceleration, skin feel
• For wax melts: Scent throw, appearance, melt consistency

Document your results in your blending journal. This testing might seem like extra work upfront, but it saves you from ruining large, expensive batches.

One failed 5kg batch will cost you far more in wasted materials than making two 200g test candles ever will.

Simple Fragrance Load Formula (Use This Every Time)

Here's the formula you'll use for every batch:

Base weight × Desired fragrance % = Fragrance oil amount

Real-World Examples:

Example 1:
750g wax × 0.07 (7%) = 52.5g fragrance oil

Example 2:
1200g soap base × 0.03 (3%) = 36g fragrance oil

Example 3:
300g wax (for 3 small test candles) × 0.08 (8%) = 24g fragrance oil

Quick conversion reminder:

• 6% = 0.06
• 7% = 0.07
• 8% = 0.08
• 9% = 0.09
• 10% = 0.10

Common Mistakes to Avoid

Mistake 1: Assuming Maximum Load Is Best

More isn't always better. Start lower and work your way up based on actual performance.

Mistake 2: Measuring by Volume

Always use weight. Volume measurements lead to inconsistent results.

Mistake 3: Ignoring IFRA Limits

"It smells fine" doesn't mean it's safe. Check certificates every time.

Mistake 4: Not Testing First

Jumping straight to large batches without testing is a costly gamble.

Mistake 5: Using the Same Load for Every Fragrance

Each oil performs differently. What works for vanilla won't necessarily work for eucalyptus.

Final Takeaway: Find Your Sweet Spot

Fragrance load isn't about using the maximum possible oil. It's about finding the sweet spot where scent throw, performance, safety, and cost efficiency all align.

That sweet spot will be different for:

• Different wax types
• Different fragrance oils
• Different product formats
• Different environmental conditions

The only way to find it is through careful calculation, methodical testing, and detailed documentation.

When you get fragrance load right, everything else in your product improves. Your candles burn cleaner. Your soaps smell consistent. Your customers come back. And you stop wasting expensive fragrance oil on batches that don't perform.

Start with the formula, follow the guidelines, test your results, and refine from there.

That's how professionals do it and now you know how too.