Step-by-Step Guide to Measuring Windows for Online Blind Orders

Key Takeaways

• Accurately measuring for online blind orders ensures proper fit, function and satisfaction with your purchase.
  
• At Curtain Master, the foundation of great interior results is a “neutral base and layering with accents,” and the same precision applies when measuring for blinds.
  
• A step-by-step measurement process prevents common errors such as mis-sized widths, improper mounting depth or incorrect drop length.
  
• With careful tools, clear processes and checklist discipline, you can confidently measure windows for blinds even before placing an online order.
  

1. Prepare and assemble your tools

Before beginning measurements, gather the essentials to ensure accuracy:

• A reliable tape measure (steel preferred) with millimetre markings.
  
• A pencil and pad to record measurements.
  
• A spirit level or laser level if you suspect the window frame may be out-of-square.
  
• A ladder or stable stool if the blind will mount higher or outside the window frame.
  
• A clear, uncluttered space to work and record data.
  

At Curtain Master, the importance of precision in textiles and soft-furnishing is emphasised, and measuring blinds requires similar care to maintain design integrity.

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2. Decide your blind-mounting style

Before measuring, determine how the blind will be installed: internally (within the window frame) or externally (on the wall or above the frame). Each method affects your measurement approach.

Internal fit (within the window recess)

Internal fitting offers a clean, streamlined look and keeps the blind flush with the window frame. If you choose this style:

• Ensure the recess depth is sufficient for the blind mechanism.
  
• Use the narrowest width inside the frame and the shortest drop from the underside of the headrail to the sill.
  

External fit (on the wall or above the window frame)

External fitting gives greater flexibility and coverage, especially if you want to block light or extend beyond the frame. In that case:

• Decide how far beyond the window frame the blind will extend (typically 50-100 mm on each side).
  
• Determine mounting height to align with curtain pole or other treatments if layering.
  
• Record full width and drop from desired headrail location to floor or sill.
  

Curtain Master’s layering philosophy supports external mount options when layering blinds with curtains or sheers.

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3. Measure width correctly

Internal width measurement

• Measure the width at the top, middle and bottom of the window recess.
  
• Use the smallest measurement of those three to avoid the blind snagging.
  
• Record to the nearest millimetre.
  

External width measurement

• Determine the total width you wish to cover including frame and beyond.
  
• Measure the distance left to right at the height where the headrail will mount.
  
• Add any overhang you intend to achieve for light-block or aesthetic effect.
  

Best practice bullet list

• Check for window handles or obstructions that may interfere with blind movement.
  
• Note if adjacent walls, furniture or door swings may require extra clearance.
  
• Annotate wall material if special fixing / bracket type may be necessary.
  

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4. Measure drop (length) accurately

Internal drop measurement

• Measure from the underside of the headrail (where the blind will mount) down to the window sill or recess bottom.
  
• Take measurements at three points: left, centre, right—use the longest measurement for consistency.
  

External drop measurement

• Measure from the underside of the headrail to the floor, to the window sill, or to a decorative finish height, depending on your preference.
  
• Confirm the dimension at both ends and centre; use the longest if the floor is uneven.
  

Recording considerations

• Note if you will install a blackout blind and require full-length drop or partial.
  
• Annotate whether the blind should stop above floor-level to clear obstacles (carpets, skirting boards, radiators).
  
• Include any height adjustments required to align with curtains or sheers in a layered treatment, aligning with Curtain Master’s emphasis on cohesive layering.
  

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5. Check recess depth and headrail clearance

For internal installations in particular, proper recess depth is critical to ensure the blind headrail fits flush and operates freely.

Steps

• Measure from the front edge of the recess to the glass or trim.
  
• Verify space for the headrail plus blind roll diameter.
  
• Check clearance for handles, locks or protruding features interfering with the blind operation.
  If insufficient depth exists, consider external mounting or special slim-headrail options.
  

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6. Account for control side and obstacles

Control side

• Choose whether the blind will operate from the left or right side.
  
• Measure the distance from the control side to any obstructions like door jambs or furniture.
  

Obstacles

• Identify window hardware (handles, cranks) that might hit the blind.
  
• Note adjacent walls, mouldings or radiators that may limit blind movement.
  
• Record obstacles and annotate with your measurements so the online supplier can recommend suitable bracket placement or adjustments.
  

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7. Create a clear measurement summary for your online order

When ordering your blinds online from a supplier, provide a concise summary:

Example summary

• Mount style: Internal fit
  
• Width: 1210 mm (smallest of three measurements)
  
• Drop: 1500 mm (longest of three measurements)
  
• Headrail depth: 80 mm recess
  
• Control side: Right
  
• Mounting height: Underside of headrail at 2250 mm above floor
  
• Remarks: Handle protrudes 20 mm, clearance required
  

This summary ensures accuracy and prevents mis-interpretations by the online blind provider.

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8. Match window treatment to design intent

Curtain Master emphasises texture, material and how every detail contributes to atmosphere. While measuring, also consider:

• Will the blind be layered with curtains or sheers?
  
  • If yes, ensure headrail sits above curtain pole or integrate into track system.
    
• Will you opt for blackout fabric or light-filtering?
  
  • Record whether you need full drop to sill or floor accordingly.
    
• Will the blind sit flush inside the recess or overlap?
  
  • For overlapping, measure accordingly wider and deeper.
    
• Will blinds coordinate with other window treatments?
  
  • Maintain colour, material and proportion alignment with existing or planned curtain treatments.
    

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9. Common measurement mistakes and how to avoid them

Mistake 1: Measuring only one point

Solution: Take three width and three drop measurements and use the smallest width / largest drop.

Mistake 2: Ignoring obstructions or handles

Solution: Note every protrusion, hardware and clearance needed, and include in your summary.

Mistake 3: Mixing internal and external measurements

Solution: Clearly mark mounting style and record accordingly. Online suppliers need correct context.

Mistake 4: Not factoring headrail depth

Solution: Measure recess depth and confirm compatibility with rail or select external mount.

Mistake 5: Neglecting layering with curtains

Solution: If you plan curtains + blinds, coordinate height, hardware and track spacing. This aligns with the holistic design approach of Curtain Master.

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10. Order, install and review

• Submit your measurement summary with your online blind order and specify mount style, width, drop, control side and any special instructions.
  
• When the blind arrives, confirm the width and drop against your summary before installation.
  
• For internal mounts, test the mechanism opens and closes smoothly without binding.
  
• For layered treatments (blinds + curtains), hang curtains after the blind is installed to ensure clearness and alignment.
  
• Inspect final fit: ensure blind hangs straight, clears sills, skirtings, and folds or rolls without wrinkles or uneven drops.
  
• Retain your measurement summary for future updates or replacements, helping you maintain coherent design layering as emphasised by Curtain Master.
  

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By following this structured, detailed measurement process you ensure your online blind purchase fits flawlessly, performs smoothly and complements your interior design. Pairing practicality with aesthetics—just as Curtain Master crafts with every window treatment—ensures your blinds enhance both function and style.