Measuring Windows for Blinds – SA DIY Guide

 Accurate window measurements are the difference between blinds that look “off” and blinds that fit like they were made for your home. Use this step-by-step measuring guide (ideal for Gauteng homes, including Johannesburg and surrounds) to avoid ordering errors and get a clean, professional finish.

Step-by-Step Instructions for Measuring Windows for Blinds

Blinds can transform any space – but only if they fit correctly. Many South African homeowners attempt DIY measurements, only to end up with blinds that are too wide, too short, uneven, or unable to open smoothly.

At Fix A Blind, we’ve found that inaccurate measuring is the most common reason blinds fail to look or function the way they should. This is especially common in older Johannesburg and Gauteng homes, where window frames aren’t always perfectly square.

Taking the time to measure properly saves money, prevents installation issues, and ensures your blinds look custom-made for your home. If you’re based in Gauteng (Johannesburg, Pretoria and surrounds), accurate measurements also help prevent delays when ordering or booking installation.

Tools You Need Before You Start

To avoid mistakes, make sure you have the right tools on hand:

• Steel tape measure (more accurate than fabric tape)

• Pencil for marking

• Notepad or phone to record every measurement

• A level, if your window frame may be uneven

Even a few millimetres can affect how blinds sit inside a frame or recess. Always measure carefully, write everything down, and double-check before placing an order. Tip: take measurements in millimetres (mm) for the most accurate ordering.

Inside Mount vs. Outside Mount – Which One Is Best?

Inside Mount (Blinds Fitted Inside the Recess)

This creates a clean, modern look and works best when the window recess is deep and square. However, accuracy is critical – even a small measurement error can prevent proper fitting.

Outside Mount (Blinds Fixed Above & Covering the Window)

This option covers the entire frame and works well for shallow recesses or when maximum light control is needed. It is also more forgiving if your window isn’t perfectly square.

At Fix A Blind, we help clients choose the best mounting option depending on their home layout and aesthetic preference. For Gauteng homes, we often recommend the best fit based on sunlight direction, privacy needs, and room use (bedrooms vs offices).

Step-by-Step Instructions for Measuring Your Windows for Blinds

Inside Mount Measurements

1. Width: Measure at the top, middle, and bottom of the recess.

   • Use the narrowest measurement to ensure the blinds fit even if the frame is slightly uneven.

2. Height: Measure on the left, centre, and right.

   • Use the longest measurement for full coverage.

Outside Mount Measurements

1. Width: Measure the area you want the blind to cover.

   • Most homeowners add 5-10 cm on each side to increase privacy and block more light.

2. Height: Measure from the top fixing point down to where you want the blind to end – usually below the sill or skirting.

Important: Always label your measurements clearly as width (W) and height (H). Swapping the two is one of the most common and costly mistakes. If you’re sending measurements to a supplier or installer, include the room name (e.g., “Main Bedroom”/“Office”) to avoid mix-ups.

Common Measurement Mistakes – And How to Avoid Them

Even confident DIYers get tripped up by simple errors:

• Mixing centimetres and millimetres

• Rounding measurements instead of recording the exact number

• Ignoring uneven window frames, especially in older South African homes

• Incorrectly measuring bay windows, sliding doors, or angled frames

   

Frames that aren’t perfectly square can make blinds appear crooked even when manufactured correctly. When in doubt, precision and caution are key. If the frame looks skew, use your level and take the “best-fit” measurement (narrowest width for inside mount).

When You Should Call a Professional

Measuring windows isn’t difficult, but it does require accuracy. If your windows are non-standard or you want peace of mind, let a professional handle it.

At Fix A Blind CC, we offer free measuring services to ensure your blinds are made correctly the first time. This prevents unnecessary delays, costly reorders, and installation frustration. We assist clients across Gauteng, including Johannesburg and Pretoria.

Many of our clients say they felt an immediate sense of relief knowing the measurements were handled by experts – especially when investing in high-quality blinds that should fit perfectly.

Book Your Free Measuring Consultation

Don’t risk ordering blinds that don’t fit. If you want a perfect, hassle-free installation, Fix A Blind CC is here to help.

Visit our website to schedule your measuring appointment, or contact our team today to get started.
Perfect blinds start with perfect measurements – let us handle the details.