What size are droppers?
Droppers come in sizes that match the bottle they fit, and for standard dropper bottles the key size is the DIN18 (GL18) thread. A DIN18 dropper fits DIN18 bottles of 5, 10, 15, 20, 30, 50 and 100 ml, while the glass pipette inside is cut to a length that suits the bottle height.
Thread size comes first
When people ask about the size of a dropper, the most important dimension is not the volume but the neck thread. The dropper collar screws onto the bottle neck, and the two must have the same thread standard. DIN18 is a very common neck finish for small glass dropper bottles used for cosmetics, essential oils, CBD oils and food supplements. A dropper with another thread, such as 20/410 or 24/410, will not fit a DIN18 bottle.
Bottle sizes that fit DIN18 droppers
The same dropper assembly can be used across a family of bottle volumes, with the pipette length changing to match.
| Bottle volume | Approximate pipette length |
|---|---|
| 5 ml | about 48 mm |
| 10 ml | about 58 mm |
| 15 ml | about 63 mm |
| 20 ml | about 70 mm |
| 30, 50 and 100 ml | longer pipettes, matched to the bottle |
There is no 60 ml size in this range. If you need a volume between 50 and 100 ml, the nearest choices are 50 ml and 100 ml.
Pipette length and why it matters
A pipette that is too short will not reach the bottom of the bottle, leaving liquid that cannot be drawn up. One that is too long will bend or press on the base of the bottle. Standard pipettes have a straight tip with a ball end, which keeps the tip smooth and helps it sit above the bottom of the glass. The length is chosen so that the tip hovers just above the base when the collar is screwed down.
Other parts that affect size
- Teat: NBR in black or white, or TPE, with different sizes and squeeze volume.
- Collar: PP, tamper-evident, child-resistant, or aluminium in finishes such as gold, silver, matte and rose.
- Pipette type: plain, graduated with printed marks, or laser-marked.
A full squeeze of a dropper for a 10 to 30 ml bottle draws roughly a fraction of a millilitre up to about 1 ml. A typical dropper produces about 20 to 30 drops per millilitre, depending on the liquid and the tip.
Measuring before you order
If you are matching a new bottle with a dropper, measure or check three things: the neck thread, the overall bottle height and the inside depth. The pipette length should leave a few millimetres between the tip and the base. For a first order it is sensible to request samples, fill them with your own product and check that the tip reaches the bottom, the collar tightens fully and the teat gives the squeeze you want. Small differences in glass tolerance between batches are normal, so a short trial saves unpleasant surprises.
Häufige Fragen
Can I use a 10 ml dropper on a 30 ml bottle?
The thread will fit if both are DIN18, but the pipette will be too short to reach the bottom of the bottle. Use the pipette length that matches the bottle.
How do I check my bottle thread?
Look at the specification of the bottle or ask the supplier. If in doubt, order a sample and test the fit before ordering in volume.
Are all dropper bottles DIN18?
No. Other neck finishes exist, and they are not interchangeable. Always check the neck finish before buying droppers.
Choosing droppers for your product
Packaging.si supplies amber DIN18 bottles and matching droppers so that the thread, pipette length and collar work together. Free samples are available on request.
