How Do I Measure a Window for Security Bars Accurately?

Tools You Need Before You Start

Gather a steel measuring tape of at least five meters, a pencil, a notebook or phone for notes, and a small spirit level. A flexible tape can sag and give false readings, so a steel tape is more reliable for openings.

• Steel measuring tape
• Pencil and paper or a notes app
• Spirit level or phone level app
• Camera for photos of each opening

Work in millimeters and keep the same unit on every line of your notes.

Measure the Width Correctly

Measure the width of the opening from the inside edge of one frame to the inside edge of the other. Take the reading at the top, middle and bottom of the opening, because walls and frames are rarely perfectly parallel. Write down all three numbers.

When preparing for a quote, the smallest of the three readings is the one that matters most, since bars must fit inside the opening without forcing.

Measure the Height Accurately

Measure the height from the sill or bottom of the frame up to the top inside edge. Again, take three readings, at the left, center and right, because the top of a frame can be slightly out of level. Record the smallest value.

If the window has a rolling shutter box, a raised sill or a tiled reveal, note exactly where your measurement starts and ends so the installer knows the reference point.

Note the Depth and Frame Type

Depth tells the fabricator how far the bars can sit from the glass and whether they will fit inside the reveal. Measure the depth of the recess from the wall face to the glass or frame face.

• Frame material: aluminum, PVC or wood
• Recess depth in millimeters
• Whether the frame is set in the wall or flush with it

This information affects how the bars are fixed and which fixing method is suitable.

Record Obstacles and Hardware

Look for anything that might interfere with the bars. Handles, hinges, opening mechanisms, roller shutter guides, air conditioning pipes, electrical boxes and window stays all need to be noted. Mark the position of each one relative to the frame.

A simple sketch with dimensions is very helpful. Draw the opening, label the readings and mark the obstacles.

Send Photos and Measurements for a Quote

Photos make a big difference. Take one straight-on photo of the whole window, one close-up of each corner, and one of any obstacles. Include a tape measure in at least one photo to show scale.

Send the photos together with your written measurements. A technician will usually confirm the figures on site before production, so an accurate first set of numbers saves time for everyone.

Frequently asked questions

Should I measure to the inside or outside of the frame?

Measure to the inside edges of the frame, because the bars are fitted within the opening. Outside measurements include the frame itself and will be too large.

Why take three measurements instead of one?

Walls and frames often are not perfectly square or level. Three readings reveal any variation, and the smallest one ensures the bars will fit.

Do I need to measure the depth of the window?

Yes, depth affects how the bars are fixed and whether they clear the glass or handles. Record it in millimeters along with the other dimensions.

Can I send my measurements without a visit?

You can send your own measurements with photos to start the inquiry. The final dimensions are normally confirmed by measuring on site before the bars are made.

Common mistakes to avoid

The most common errors are measuring to the outside of the frame and using a flexible tape that sags. Mixing units or forgetting to note obstacles such as handles and shutter boxes also leads to delays.

Our recommendation

Measure twice, write every number down with its reference point, and include clear photos. A simple sketch showing where each measurement starts and ends is the most useful thing you can give your installer.

Summary

Measure the inside width and height at three points each, note the depth and any obstacles, and send clear photos with your numbers. Accurate measurements make the quoting and installation process smooth.

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