Neat Drape

Curtain, tablecloth & bedding size calculators

Blinds

Blind measuring guide

Measure each window three times across and three times down, decide whether the blind sits inside or outside the recess, and get the width and drop to write on the order. Save every window to one list.

Units
Where will the blind hang?

Widths, inside the recess

Drops, top of the recess to the sill

Optional: to the window frame or any handle

Ordering an inside fit

Which drop does your maker ask for?

UK guides such as Dunelm and English Blinds ask for the smallest; many US guides ask for the longest.

Order as

Recess size: the maker takes off the clearance. Exact size: you take it off.

Save to your list

91.4 cm91.2 cm91.5 cmDrops L · M · R: 121.3 cm · 121.5 cm · 121.2 cmInside the recess
The measurement used for the order is highlighted.
Width to order
91.2 cm (36 in)the narrowest width; the maker takes off the clearance
Drop to order
121.2 cm (47¾ in)the shortest of the three drops
Order as
Recess sizeRoller blind, top fix
Recess depth needed
50 mmyou measured 9 cm

Measurements look consistent.

Check the maker's own guide before ordering: some deduct for you and some do not.

Your windows

No windows saved yet. Measure one above and press Save this window; the list stays in this browser only.

How to measure a window for a blind

Use a steel tape, not a cloth one, measure every window even if they look the same, and write each number down to the millimetre or the nearest ⅛ inch.

  1. Three widths

    Measure across the recess at the top, the middle and the bottom. Old walls are rarely square. For an inside fit the narrowest is the one that counts, so the blind never catches on the sides; tiles or handles inside the recess count too.

  2. Three drops

    Measure from the top of the recess to the sill on the left, in the middle and on the right. Makers differ on which to use: UK guides tend to ask for the shortest so the blind clears the sill, many US guides for the longest so no light shows.

  3. Depth, or the overlap

    For an inside fit, check the recess is deep enough for the blind's brackets and fabric. For an outside fit, decide how far past the opening the blind runs: overlap stops light leaking round the edges.

    overlap

Inside or outside the recess?

Inside looks neat and leaves the wall clear, but needs enough depth and a fairly square opening, and a little light shows at the edges. Outside hides an uneven recess, blocks more light and suits shallow reveals; English Blinds recommends overlapping each edge by 10 cm, and Bob Vila up to 3 inches each side.

Deductions: let the maker do it

If the order form asks for the recess size, give the exact recess and the maker takes off its own clearance (Dunelm deducts 1 cm). Only take something off yourself when ordering an exact blind size, and then use your maker's figure, because it varies with the blind and the bracket.

Recess depth needed for an inside fit

BlindDepth
Roller, face fix70 mm
Roller, top fix50 mm
Wood or faux wood, 25–35 mm slats55 mm
Wood or faux wood, 50 mm slats65 mm
Aluminium venetian, 25 mm slats30 mm
Roman50 mm
Vertical75 mm
Day & night roller, face / top fix75 / 55 mm

English Blinds' figures for a blind to sit fully inside the recess. Other makers' blinds and brackets differ; check before ordering.

Sources

  • English Blinds, How to measure: narrowest width and smallest drop for a recess fit, no deductions by the customer, the recess depths in the table, and a 10 cm overlap on each edge outside the recess (only 10 cm extra on the drop when the sill sticks out).
  • Dunelm, How to measure for blinds: three widths and three drops, the smallest of each inside the recess, a 1 cm width deduction made by the maker, and a 5 cm (2 in) overlap either side outside the recess.
  • Bob Vila, How to measure for window blinds: narrowest of three widths, longest of three heights for an inside mount, the depth check, and extending an outside mount up to 3 inches beyond each side.

Questions

Should I take anything off the width myself?

Not when the order asks for the recess size: the maker removes the clearance its blind needs, and taking it off twice leaves a gap. Deduct only when you order an exact blind size, using the figure from that maker's own guide.

My three widths are all different. Which do I use?

For a blind inside the recess, the narrowest, so it can run up and down without rubbing. If the difference is large, the gap at the widest point will show; an outside fit, sized from the widest measurement plus an overlap, hides it.

How far should an outside blind overlap the window?

Guides range from about 5 cm (2 in) to 10 cm (4 in) on each side. More overlap blocks more light round the edges, which matters for blackout blinds in bedrooms; less keeps the blind clear of nearby walls, cupboards or a second window.

What if my recess is too shallow?

Choose a blind that needs less depth, such as a top-fix roller or a slim venetian, accept that it will stand slightly proud of the wall, or fit it outside the recess, where the depth no longer matters.

Where is my saved list kept?

Only in this browser's local storage on this device. Nothing is sent anywhere. Download the CSV or print the list to keep a copy or share it with a fitter, and use Clear all to delete it.