How do you turn vessel volume into wax weight?

The vessel volume is converted to millilitres and multiplied by the fill level, then by the wax density. Most candle waxes are slightly less dense than water at about 0.9 grams per millilitre, so an 8 oz vessel holds roughly 210 grams of wax when filled to 90 percent.

Is fragrance load a percentage of wax or of total weight?

By industry convention, fragrance load is a percentage of the wax weight, not the combined total. So 8 percent on 200 grams of wax means 16 grams of fragrance oil. This tool follows that convention.

How much fragrance can I safely add?

Most waxes top out around 8-12 percent fragrance load, but soy and beeswax hold less than coconut blends. Above the safe maximum the oil can seep out, cloud the wax, or cause sooting and poor burns. Always check your specific wax's stated maximum.

Why do different waxes hold different amounts of fragrance?

Fragrance binding depends on the wax's molecular structure. Coconut and coconut-soy blends bind oil well and take higher loads; pure soy and beeswax bind less and can sweat oil if overloaded. The tool flags loads above each wax's typical ceiling.

Should I weigh or measure by volume?

Weigh everything. Candle making is a weight-based craft: weigh the wax, then weigh the fragrance to hit the exact percentage. Volume measurement of viscous wax and oil is far less accurate and leads to inconsistent scent throw.

Candle Wax & Fragrance Calculator

Mix wax and fragrance by the numbers

Consistent candles come from consistent measurements. This calculator turns a vessel volume into the wax weight you need to melt, then calculates the matching fragrance oil at your chosen load — and warns you when that load is too high for the wax you picked.

How it works

Wax is sold and used by weight, but vessels are sized by volume, so the first step is a volume-to-weight conversion using wax density:

wax volume (ml) = vessel volume × fill % 
wax weight      = wax volume × wax density   (≈ 0.9 g/ml for most waxes)

Fragrance load is, by long-standing convention, a percentage of the wax weight:

fragrance weight = wax weight × fragrance load %

Each wax also has a practical ceiling — the most fragrance it can hold before the oil seeps out or the burn suffers. Soy and beeswax sit lower; coconut blends hold more. The tool compares your load to that ceiling and flags it if you go over.

Tips and example

An 8 oz soy vessel, filled to 90%, at an 8% fragrance load:

Wax volume = 8 oz × 29.57 × 0.90 = ~213 ml
Wax weight = 213 × 0.9 = ~192 g (about 6.8 oz)
Fragrance = 192 × 0.08 = ~15 g (about 0.5 oz)

Weigh both the wax and the fragrance on a gram scale rather than measuring by volume — it is the single biggest factor in repeatable scent throw. Add fragrance at your wax’s recommended temperature and stir for two full minutes so it binds evenly.