Measuring for a barn door may seem simple—but it’s one of the most common places people go wrong. Getting the dimensions just right is key to both functionality and aesthetics. A door that’s too small won’t cover your opening properly, and one that’s too large might overwhelm the space or not glide smoothly.

At customslidingbarndoors.com we specialize in standard barn doors and creative solutions for everything from tight spaces to XXL barn doors. Here’s how to get it right the first time—and when in doubt, always call your barn door specialist at 720-500-3985.

Step 1: Measure the Width of the Opening

Start by measuring the full width of your door opening.

Then, use this simple rule of thumb:

• For standard doorways:
  Add 2 inches to each side (a total of 4 inches). This ensures proper overlap and privacy.

• For bathrooms or spaces requiring more privacy:
  Add 3 inches to each side (a total of 6 inches). This prevents gaps that can compromise privacy. Remember the doors do sit slightly off the wall.

• If there is trim around the doorway:
  Measure edge to edge of the trim, and then add 1 inch total. This helps the barn door fully cover the frame for a polished look.

Step 2: Measure the Height

From the floor to the top of the opening, take the full vertical measurement.

• In most cases, we use this height as-is or add 1 inch for better coverage.

• If ceiling or header space is limited, we’ll work with the space available and adjust the hardware or door size accordingly.

Pro Tip: Don’t Forget About Hardware Clearance

If you have less than 5.5" of space from top of opening to your ceiling let us know! We have plenty of header hack options to share or low profile clearance suggestions. 

Common Measurement Mistakes to Avoid

1. Not accounting for overlap. A door the exact width of the opening will leave gaps.

2. Ignoring trim. Measuring only the drywall-to-drywall space (inside the trim) can lead to under-sizing. Also your wall trim usually isn't square..if you don't go bigger this will be noticeable.

3. Measuring too high (or too low). Don’t guess—measure floor to top of the opening directly.

4. Assuming all doors fit all openings. Barn doors require planning, especially in bathrooms or custom setups.

When in Doubt, Call the Pros

If your doorway is oversized, undersized, oddly placed, or just confusing—we’ve seen it all. We handle everything from standard barn doors to unique and oversized barn door projects.

Got questions or a tricky situation? Give us a call at 720-500-3985. We love a good challenge.

Want help customizing your barn door?
Explore our most popular styles here, and let’s make sure your door fits perfectly.