Perfume drops, millilitres and grams
Convert any material between drops, millilitres, grams and ounces using its own density — the conversion recipes get wrong, because a millilitre of vanilla absolute and a millilitre of bergamot are not the same weight.
INPUTS
A pre-blended commercial oil. They run roughly 0.85–1.10 depending on what is in them, so 0.95 is a midpoint rather than a measurement. Check the spec sheet if you have one.
Why this needs a material at all
Millilitres to grams is the only conversion here that needs a density, and it is the one recipes get wrong. Benzoin resinoid at 1.15 g/ml is 36% heavier per millilitre than sweet orange at 0.845 — so a formula converted between the two units without naming its materials is wrong for most of its rows. Drops are worse again: 20 drops to the millilitre is an average across a pipette, not a property of the liquid, and a thin citrus oil genuinely gives more of them than a resinoid does.
Weight is the only one of these that is a measurement. Millilitres depend on temperature, drops depend on viscosity and on the pipette, and both depend on how steady your hand is. Convert to grams, write the formula down in grams, and it will still be right in a year.
RESULTS
10 ml weighs
9.500 g
Fragrance oil (unspecified) 0.95 g/ml
The same amount, every way
| Unit | Kind | Amount |
|---|---|---|
| Grams | weight | 9.500 g |
| Millilitres | volume | 10.000 ml |
| Drops | estimate | 200 drops |
| Ounces (weight) | weight | 0.3351 oz |
| Fluid ounces | volume | 0.3381 fl oz |
One millilitre weighs
0.950 g
One gram measures
1.053 ml
Fixed conversions, for reference: 20 drops to a millilitre, 28.3495 g to an ounce by weight, and 29.5735 ml to a US fluid ounce. Only the drop figure is an approximation — the other two are definitions, and an ounce and a fluid ounce are different things measuring different quantities.
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How this is worked out
Everything here routes through millilitres, so a density is applied exactly once and never twice. Drops convert at 20 to the millilitre, ounces at 28.3495 g each, fluid ounces at 29.5735 ml each — and only the drop figure is an approximation, because it is a property of the pipette rather than of the liquid. The conversion that needs the material named is millilitres to grams, and it is the one recipes get wrong: Benzoin resinoid at 1.15 g/ml is about 36% heavier per millilitre than sweet orange at 0.845, so a formula converted between the two units without naming its rows is wrong for most of them. Densities in the list are working figures with real spread — two bergamots from two houses genuinely differ — so the tool also takes your own number straight off a supplier's spec sheet, which is the figure that binds.
ml = g ÷ specific gravity g = ml × specific gravity
ml = drops ÷ 20 an average, not a property of the liquid
g = oz × 28.3495 ml = fl oz × 29.5735
an ounce and a fluid ounce measure different quantities
Questions makers ask
How many drops are in 10 ml?
About 200, taking 20 drops to the millilitre. Treat that as an average rather than a measurement — drop size follows surface tension and viscosity, so a thin citrus oil gives noticeably more drops per millilitre than a resinoid does, and the same pipette behaves differently with each. It is the reason drops are fine for finding a blend and poor for repeating one.
How do I convert perfume ml to grams?
Multiply by the material's specific gravity. This is the conversion that actually needs a tool, because it needs a different number for every row of a formula: 10 ml of sweet orange is 8.45 g and 10 ml of benzoin resinoid is 11.50 g — about 36% apart. A recipe that converts between the two units without naming its materials is wrong for most of its rows.
What is the specific gravity of a fragrance oil?
Commercial fragrance oils run roughly 0.85 to 1.10 depending on what is in them, so 0.95 is a reasonable midpoint if you have nothing better. Your supplier's spec sheet is the figure that binds, and the tool takes your own number if you have it. Naturals vary too: citrus sits near 0.845, resins and absolutes above 1.0.
Is an ounce the same as a fluid ounce?
No, and mixing them up is a real source of ruined batches. An ounce is a weight — 28.3495 g. A US fluid ounce is a volume — 29.5735 ml. They only coincide for a material with a specific gravity near 0.96, which almost nothing in perfumery is. If a recipe says "oz" without saying which, look at whether it is asking you to weigh or to pour.
Should I measure perfume by weight or by volume?
By weight, always, if you intend to make the same thing twice. Weight is the only one of these that is a measurement: millilitres depend on temperature, drops depend on viscosity and on the pipette, and both depend on how steady your hand is. Convert once, write the formula down in grams, and it will still be right in a year.
Why does my formula weigh less than the bottle size?
Because most of it is alcohol, which is about a fifth lighter than water. A 30 ml perfume weighs closer to 25 g than 30 g. That is normal and it is the same reason a formula measured by volume comes out weaker than one measured by weight at the same stated percentage.
Read before your next batch
- Make your own perfume Blend the compound, dilute it into alcohol, then leave it alone for a month. Everything else is detail — and this page has the detail.
- Where to buy perfumers alcohol It is cheap, it is not restricted, and it is still the hardest thing in this craft to get hold of. Here is why, and what to ask for.
- Perfume maceration: how long to age a perfume Maceration is the word for leaving it alone. It is also the difference between a blend and a perfume, and it is the step nearly everyone skips.
- Perfume notes explained: top, heart and base Notes are not ingredient categories. They describe how fast something leaves your skin — and that one fact explains everything else about the pyramid.