Measurement Conversion Chart

When working with essential oils, the most common conversions you typically need are:

  • 20 drops = 1 ml
  • 100 drops =1 tsp = 5 ml
  • 300 drops = ½ oz = 15 ml
  • 600 drops = 1 oz = 30 ml

But, sometimes a little more detail is in order:

Drops Teaspoons Ounces Drams Milliliters
10 drops 110 tsp 160 oz ~18 dram ~½ ml
12 12 drops 18 tsp 148 oz 16 dram 58 ml
25 drops ¼ tsp 124 oz 13 dram 1 ¼ ml
50 drops ½ tsp 112 oz 23 dram ~2 ½ ml
100 drops 1 tsp 16 oz 1 13 dram ~5 ml
150 drops 1 ½ tsp ¼ oz 2 drams ~7 12 ml
300 drops 3 tsp ½ oz 4 drams ~15 ml
600 drops 6 tsp 1 oz 8 drams ~30 ml
24 tsp 8 tbsp 4 oz ½ cup ~120 ml
48 tsp 16 tbsp 8 oz 1 cup ½ pint
96 tsp 32 tbsp 16 oz 2 cups 1 pint

Source: Aromatherapy: A Complete Guide to the Healing Art by Kathi Keville and Mindy Green.

This chart makes the common assumption that 20 drops = 1 ml. However, always remember that drops vary in size based on liquid viscosity and the dropper or pipette you are using. If you want certainty, conduct a test with a calibrated beaker to see how many drops = 1ml.

For example, in Mandy Aftel’s book, Essence & Alchemy, she assumes that 40 drops = 1ml. Double the common assumption! I recently tested this myself using a glass eyedropper and found it to be absolutely accurate. So definitely check before moving forward with a recipe or formula.

Eden Botanicals offers a more detailed range for how many drops = 1 ml, and so far this matches my experience as well:

1 ml = 30-50 drops, depending on viscosity and size of the drop; aprox. 40-50 drops per ml for very mobile oils such as some citrus oils and fir needle oils; more viscous (thicker) oils such as Vetiver and Sandalwood will be approx. 30-40 drops per ml.

1 oz = 30 ml. Using these measurements, it can be extrapolated that there are approx. 900-1500 drops per ounce.

Notice how there are more than double the number of drops in the first estimate (600 drops = 1oz) and the Eden Botanicals estimate (900-1500 drops = 1oz)? Yikes.

This variability is why professional perfumers measure in weight with accurate lab scales. Still, if you’re just messing around at home, drops are far easier and most beginner recipes are calculated in drops. For more conversions, try this handy Volume Unit Converter site.


Aging Perfume Blends


Aging by Bob AuBuchon

I’m not a particularly patient person. So – ARGH! – I was horrified to discover that in this perfume crafting business you need to let a blend age to let the scents marry. Fragrances will change as they mature, and after aging they become much more seamless, rounded, and soft.

Le sigh.

Advice about this process varies. Generally speaking, there are two times you can age a blend: before and after dilution.

Which brings up another point: Most people advise combining your raw materials to create your fragrance blend first, prior to adding it to your carrier medium.

After mixing your blend of raw materials, store it in a dark bottle in a cool place to let it age. Sources vary on how long. Some DIYers seem to skip this step, others recommend anywhere from 1 week to 2-3 weeks.

The most commonly given advice seems to be 48 hours to 1 week, averaging out at around 4 days.

Then, sniff the blend. If you’re happy with it, dilute with a carrier oil (jojoba or fractionated coconut oil are best; they have the longest shelf life of oils) or perfumer’s alcohol (much better shelf life than oils – basically indefinite).

After dilution, most sources agree you need to let an alcohol-based perfume age 4-6 weeks. For an oil-based perfume, try 3 days to a week.

Oh, the waiting! I guess I’ll have to get used to it.


  • In Essence & Alchemy, Mandy Aftel recommends letting an alcohol-based blend mature for at least a week, and up to a month if you can stand it (this is after dilution).
  • In Perfume: The Art and Craft of Fragrance, Karen Gilbert recommends letting an alcohol-based blend macerate for a week or two before using.

How to Smell


  • the layers of a smell (one-dimensional or complex and layered)
  • the shape of a smell (pointed, sharp, rounded, dull)
  • the memories it conjures
  • the feelings it arouses

Ask yourself: If this fragrance were a color, what would it be? Allow the smell to open itself to you, and discover whatever about it is most beautiful, most remarkable to you.”  – Mandy Aftel, Fragrant: The Secret Life of Scent