Getting the measurement right is the most important step in ordering a bifold door. Order too small and you have gaps. Order too large and it won't fit. There's no middle ground.
This guide walks you through exactly how to measure your opening — and what those numbers mean when you place your order.
What You're Measuring: The Rough Opening
The rough opening is the framed hole in your wall — the actual space available for the door unit. Your bifold door must fit inside this rough opening with a small tolerance for shimming and adjustment.
Key principle: Your rough opening should be slightly larger than the door unit you order.
Standard tolerance: ½" on each side (width) and ½" on top (height).
So if your rough opening is 96" wide × 80" tall, you'd order a door unit that is 95" wide × 79½" tall — or simply order the 96"×80" unit and account for shimming.
In practice: order the door size that most closely matches your rough opening, and our team will confirm the fit when you call.
Step-by-Step Measurement Guide
Step 1: Measure the Width
Measure the width of your rough opening at three points:
- Top of the opening
- Middle of the opening
- Bottom of the opening
Use the smallest measurement. Openings are rarely perfectly square — using the smallest width ensures the door will fit.
Write down: Width = [smallest measurement]"
Step 2: Measure the Height
Measure the height of your rough opening at three points:
- Left side
- Center
- Right side
Use the smallest measurement.
Important: If you're installing on a concrete floor, account for the track height. Our bottom tracks are typically ¾"–1" tall. Your effective opening height is reduced by this amount.
Write down: Height = [smallest measurement] minus track height"
Step 3: Check for Level, Plumb, and Square
Before ordering, verify:
Level: Is the floor flat? Use a 4-foot level across the width of the opening. Any slope will need to be shimmed during installation.
Plumb: Are the side jambs vertical? Check with a level on each side.
Square: Are the corners at 90°? Measure diagonally corner-to-corner. Both diagonal measurements should be equal. If they differ by more than ½", the opening needs to be squared before installing a bifold door.
Standard vs Custom Sizes
Our bifold doors come in 20 standard sizes. If your measurement falls between standard sizes, you have two options:
Option 1 — Order the next size down. A 95" opening can use a 96"×80" door with minimal shimming. A 100" opening can use a 96" door (4" gap, handled with trim/casing).
Option 2 — Custom order. Built to any exact dimension. Call us at (818) 570-2424 with your exact rough opening measurements and we'll spec the right door.
Standard Size Reference
| Width | Height Options | |---|---| | 60" (5ft) | 80" or 96" | | 72" (6ft) | 80" or 96" | | 96" (8ft) | 80" or 96" | | 108" (9ft) | 80" or 96" | | 120" (10ft) | 80" or 96" | | 144" (12ft) | 80" or 96" | | 168" (14ft) | 80" or 96" | | 192" (16ft) | 80" or 96" | | 216" (18ft) | 80" or 96" | | 240" (20ft) | 80" or 96" |
What to Tell Your Supplier
When you contact Direct WinDoors, have these numbers ready:
- Rough opening width (smallest measurement)
- Rough opening height (smallest measurement, minus track allowance)
- Floor type (wood subfloor, concrete, tile — affects anchoring)
- Which direction you want the door to stack (left, right, or split)
- Color preference (black, white, or custom RAL)
That's all we need to confirm your order.
Common Mistakes to Avoid
Measuring the existing door frame instead of the rough opening. Always measure the framed hole, not the existing door or casing.
Not accounting for track height. Measure from finished floor up, then subtract ¾" for the track.
Using the largest measurement instead of smallest. If the opening is out of square, the door must fit the smallest dimension.
Forgetting stacking clearance. When fully open, bifold panels stack against one side. Make sure there's clearance on that wall for the stack depth (typically 4"–8" depending on panel count).
Ready to Order?
Browse our full bifold door collection or call us with your measurements.
📞 Call (818) 570-2424 — we'll confirm your sizing and provide a freight quote. 🌐 directwindoors.com | 📩 info@directwindoors.com
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