How Many Packers Do You Need per Window or Door? (Bulk Quantity Guide for Installers)
Why Installers Need a Bulk Quantity Guide
Professional window fitters, door installers, and uPVC fabricators rarely order packers one box at a time.
They work on multiple frames per day, across different sites, and need to estimate:
- Pack usage per window
- Total packers required per job
- Which thicknesses are used most frequently
- How many mixed sets or bulk single-size boxes to buy
This guide provides a realistic, industry-based estimate of how many glazing, frame, and door packers are required for an average installation — helping trade customers order the right quantities in bulk.
How Many Packers Are Used in a Typical uPVC Window?
On average, a single uPVC casement window requires:
- 6 to 12 packers
depending on frame size, sash configuration, and how out-of-square the opening is.
Standard usage per window:
- 2 bottom setting blocks (always required)
- 2–4 toe-and-heel packers
- 2–4 side stabilising packers
Total average range:
Minimum: 6 packers
Maximum: 12 packers
Large windows: up to 16 packers
Fabricators and installers doing multi-unit jobs should plan based on the higher end to avoid shortages.
How Many Packers for a Door?
Doors require more packers than windows because of their weight and the importance of frame alignment.
A typical composite or uPVC door needs:
- 2 bottom packers
- 4–6 toe-and-heel packers
- 4–6 frame alignment packers
Total average:
10 to 16 packers per door
Heavy or oversized doors: 20+ packers may be used.
Door installers should always order bulk quantities, especially of 3mm, 4mm, and 5mm sizes.
How Many Packers for Manufacturing and Fabrication?
Fabricators who pre-prepare frames before glazing use packers in:
- Reinforcement areas
- Mullion and transom junctions
- Threshold connections
- Outer frame squaring
Most fabricators use set patterns and high volumes of specific thicknesses.
Typical usage:
- 4–10 packers per fabricated frame
- Consistent sizes (usually 3mm and 5mm)
Fabricators should buy in bulk single-size boxes, not mixed sets.
Breakdown of Packers Used by Thickness (Real Trade Patterns)
Across thousands of installations, the usage ratio typically looks like this:
- 3 mm packers – used in ~40% of all packing
- 4 mm packers – used in ~25%
- 5 mm packers – used in ~20%
- 1 mm / 2 mm / 6 mm+ – used in ~15% combined
This means trade buyers should stock heavily in:
- 3 mm
- 4 mm
- 5 mm
And keep smaller quantities of less-used sizes.
How Many Boxes Should a Trade Installer Buy?
For installers completing 20–40 windows per month, recommended stock levels are:
Single-size bulk boxes:
- 3 mm: 1–2 boxes of 1,000
- 4 mm: 1 box of 1,000
- 5 mm: 1 box of 1,000
Mixed packs:
- 2–3 mixed sets for unusual gaps or onsite variations
Installers rarely use mixed sets exclusively — they are for flexibility only.
For door installation teams:
- Add 1 additional box of 5 mm
- Add 1 box of 6 mm for heavy composite doors
This ensures zero downtime on site.
How Many Packers Are Needed for Large Projects?
If you work on new-build housing, high-rise apartments, or commercial developments, you should calculate:
Per 10 windows:
Approx 80–120 packers
Per 50 windows:
Approx 400–600 packers
Per 100 windows:
Approx 800–1,200 packers
Contractors should order by the case, not individual boxes — especially for the high-usage sizes (3mm / 4mm / 5mm).
How Many Packers for Out-of-Square Openings?
Older properties or masonry variations often require more packers.
Sign of an out-of-square opening:
- Gaps differ significantly top to bottom
- Sash catches on the bottom or lock side
- Frame twists when fitting
Expect to use:
- 12–18 packers per window
especially of 1 mm, 2 mm, and wedge packers for adjustment.
Bulk mixed sets are ideal for this type of work.
How Many Packers Should You Keep in Your Van?
Professional installers typically carry:
- 1 mixed set for flexibility
- 3–5 bulk boxes (3mm/4mm/5mm)
- 1 box of bridge packers
- 1 box of wedge packers
- 1 box of 6–10 mm larger packers
This setup prevents shortages mid-job and reduces return trips.
Final Recommendations for Bulk Buyers
For ongoing trade work:
- Buy bulks of 3mm, 4mm, 5mm
- Buy one bulk of 6mm for heavier doors
- Keep mixed sets for odd sizes
- Stock bridge packers for frame fixings
- Use wedge packers for precision adjustments
This ensures you can install windows and doors efficiently without running out of essential sizes.