Quick answer: Dip tube length is measured from the underside of the closure gasket — the FBOG (from bottom of gasket) point — to the tip of the tube inside the bottle. For reliable evacuation it must reach the lowest corner of the bottle base, which in practice means cutting it 1–4 cm longer than the FBOG depth so the tube curves along the bottom instead of hovering above the last few millilitres of product.
Measure the FBOG depth and the bottle diameter, add the bend allowance, then send both the gasket thickness and the dip tube length to your pump or sprayer supplier before they cut tubes for mass production.
Most packaging complaints that reach a brand’s inbox are not about the bottle — they are about the last 5 ml. A pump that sputters at 90% empty, a serum that will not draw, a sprayer that needs twenty primes: all trace back to a tube cut to the wrong length. Statista’s worldwide fragrance market forecast puts 2026 revenue at about US$56.6 billion, growing at roughly 4.28% a year — and nearly every bottle inside that figure ships with a pump, sprayer or dropper whose tube must match its container to the millimetre.
What Is Dip Tube Length and Why Does It Decide Fill Yield?
The dip tube is the thin flexible tube that hangs from the pump engine into the product. Its dip tube length sets two things at once: how much of the formula the consumer can actually dispense, and how stable the spray or dose is over the life of the pack. Too short and the pump draws air while product is still visible through the glass; too long and the tube coils, kinks, or pushes the pump body up out of its seating on the bottle neck.
The measurement that matters is not the tube itself — it is the space it has to fill. The FBOG dimension runs from the bottom of the gasket seat down to the inside floor of the bottle at its lowest point, because glass bases are rarely flat inside and base thickness varies by mould cavity.
Getting this wrong is expensive in a way that is invisible on the invoice. If a consumer cannot finish a glass perfume bottle with 8–10% of juice left, the review says “pump stopped working” — not “tube was 6 mm short.” The brand absorbs the blame.
- Under-length tube: air lock in the final third of the bottle, inconsistent spray, wasted product.
- Over-length tube: tube bends into the corner so tightly it pinches, or lifts the engine and causes leakage at the crimp or thread.
- Correct tube: reaches the bottom corner, bends in a smooth radius, delivers to the last usable millilitre.
How to Measure Dip Tube Length: The FBOG Method
Industry suppliers converge on the same practical workflow, and it is worth quoting one directly. As one packaging supplier summarises it, “the tube should just touch the corner of the bottle bottom” (Fragrance Package, perfume spray pump guide). The FBOG method turns that instruction into repeatable numbers:
- Seat the closure on the empty bottle. Fit the pump or sprayer exactly as it will be crimped or screwed in production.
- Mark the gasket underside. This is your zero point — the FBOG reference line.
- Measure from that line to the lowest inside point of the base. Use a depth gauge or a marked rod, and repeat on three bottles from the same mould cavity; base thickness varies.
- Add the bend allowance. A supplier’s rule of thumb is to add three-quarters of the bottle diameter to the FBOG depth, which in practice puts the tube 1–4 cm longer than the straight measurement so it curves along the base rather than standing vertically (Bottle Container, dip tube length guide).
- Send two numbers to the tube cutter: dip tube length and gasket thickness. Suppliers cut tubes against both, because a thicker gasket effectively shortens the tube inside the bottle.
| Parameter | What to measure | What to send the supplier |
|---|---|---|
| FBOG depth | Bottom of gasket seat to lowest inside base point | Millimetres, plus the mould cavity sampled |
| Bottle diameter | Widest internal span at the base | Used for the three-quarter bend allowance |
| Dip tube length | FBOG depth + bend allowance | The cut length itself, with tolerance |
| Gasket thickness | Measured on the actual closure supplied | Confirm it is unchanged before reordering |
| Neck finish | Thread/GPI code on the bottle neck | Locks closure and tube as one matched set |
Bent Tube vs Straight Tube: Which Should You Specify?
Once you know the FBOG depth, the real decision is geometry. A straight tube ending at floor level looks cleaner in clear glass but stops drawing as soon as the liquid drops below the cut end; a longer tube that bends along the base follows the product into the corner.
| Item | Bent (curved to the base) | Straight (vertical) |
|---|---|---|
| Cut length | FBOG depth + 1–4 cm allowance | FBOG depth only |
| Residual product | Lowest achievable; draws from the corner | Higher; product below the cut end is stranded |
| Appearance in clear glass | Visible curve at the base | Clean vertical line |
| Best for | Serums, oils, fragrance, any high-value fill | Design-led packs where residual loss is acceptable |
How Dip Tube Length Changes by Bottle Type
The calculation is universal; the tolerance you can live with is not. Narrow-neck bottles amplify errors, while wide-mouth and square formats forgive more length because the tube has room to curve.
- Dip tube length for perfume bottles: the tightest tolerance in the range, because crimp and screw pumps output only 0.07–0.15 ml per spray — a short tube shows up immediately as uneven atomisation or a spray that dies before the bottle is empty. See our perfume bottle range for neck options.
- Essential oil and serum droppers: the pipette replaces the dip tube, but the same FBOG logic applies — the glass tube must clear the base without touching it, or the tip chips.
- Lotion and treatment pumps: higher-viscosity formulas need the tube to sit off the floor, not against it, so the suction port is not blocked by the base. Ask for a slight stand-off rather than full contact.
- Reed diffusers and refill packs: long, narrow bottles with deep FBOG values — measure from the collar seat, not from the bottle lip.
Tube, gasket and neck work as one system, which is why essential oil bottles and fragrance packs are usually specified with the closure in the same RFQ.
Buyer tip: if you buy bottles and pumps from two different factories, send one filled-free bottle sample to the pump supplier and ask them to return the FBOG length, gasket thickness and cut tube length they used. Keep those three numbers in your spec sheet — they are what makes a reorder repeatable.
Five Dip Tube Mistakes That Trigger Customer Complaints
These are the failure modes buyers report most often — each has a measurable cause:
1. Tube cut to the nominal bottle height
Catalogue heights are external. The FBOG depth is shorter by the base thickness and the neck recess, so a tube cut to the drawing height will always be too long and will kink at the shoulder.
2. Ignoring gasket thickness on a reorder
A closure change — even within the same supplier — can shift the gasket from 1 mm to 2 mm and silently shorten the effective tube by a millimetre. Re-verify the cut length on every purchase order revision, not every year.
3. No bend allowance
Straight-cut tubes look precise on paper and under-deliver in the field. Allow the 1–4 cm curve described above unless the design brief explicitly requires a vertical tube.
4. Tube material reacting with the formula
Dip tubes are not chemically inert to everything. Suppliers note that a tube turning yellow is a material reaction with the fragrance oils rather than a cosmetic defect (Fragrance Package) — a compatibility signal worth catching at sample stage, not after launch.
5. No leak or vacuum test before bulk
Tube length and sealing quality are different problems that look identical to a consumer. A vacuum leak test on filled, assembled samples separates a badly cut tube from a badly crimped closure before you commit to a production run.
“The tube should just touch the corner of the bottle bottom.” — Fragrance Package, Perfume Spray Pumps: Types, Structures, Troubleshooting
How Tube Length Affects MOQ, Sampling and Cost
Tube cutting is a conversion step, not a moulding step, so it rarely drives MOQ on its own — but it does drive sample lead time, because a custom cut length needs a bottle in hand, a measurement confirmation and a cutting setup before the first assembled sample ships.
- Standard stock tube lengths: fastest route, if your FBOG depth plus allowance lands inside a stocked range.
- Custom dip tube length: adds a confirmation loop, but removes the residual-product complaint class for premium fragrance and serum.
- Assembled sample approval: test in the real bottle with the real formula viscosity, not in water.
Because tube, gasket and neck are specified together, our customization service handles the measurement sheet as part of the RFQ rather than as a later add-on — which is the cheapest way to avoid a second tooling round.
FAQ: Dip Tube Length Questions Buyers Ask
What is the correct dip tube length formula?
FBOG depth (bottom of gasket to lowest inside base point) plus a bend allowance of roughly three-quarters of the bottle diameter — in practice 1–4 cm of extra length — so the tube curves along the base instead of standing on it.
Should the dip tube touch the bottom of the bottle?
For fragrance and low-viscosity formulas, yes: it should reach the corner of the base so the pump can draw to the last usable millilitre. For viscous lotions, keep a small stand-off so the suction port is not sealed against the glass.
Why does my pump stop spraying before the bottle is empty?
Usually a sprayer dip tube that ends above the product level, or one that has kinked because it was cut too long for a narrow neck. Check the tube against the base first, then leak-test the closure.
How much too long can a dip tube be?
In a wide-mouth bottle a few millimetres is harmless, because the tube curves into the base. In a narrow 15–20 mm neck a dip tube too long cannot escape sideways — it kinks at the shoulder, so specify the cut length instead of taking the nearest stock size.
Get Your Tube and Bottle Matched Before Production
A dip tube length is a 20 mm decision that shapes the last third of your customer’s experience. Measure the FBOG depth on three bottles, add the bend allowance, fix the gasket thickness in your spec sheet, and put the cut length on the purchase order next to the neck finish.
Need bottle and closure supplied as one measured set? Send your drawing or sample, target fill volume and formula type — we return the FBOG measurement, the recommended cut length and a sample plan.
Sources: Statista Fragrances worldwide market forecast (2026); Fragrance Package, Perfume Spray Pumps: Types, Structures, Troubleshooting (2026); Bottle Container, How to make a dip tube length of pump or sprayer to match the bottle.