How to Measure Shades

Shades are measured from the window opening, and inside mount and outside mount need different numbers. Use the finder below, or follow the full step-by-step guide to get the exact size to order. Measuring curtains or drapes instead? See How to Measure Curtains.

Shades Measuring Instruction

EaseEase blinds and shades start with one decision — which type of mounting is right for you — before you measure your windows.

How to Measure Shades — Quick Answer

Shades are measured from the window opening, not the rod. First decide inside mount (inside the window recess, for a clean built-in look) or outside mount (on the wall or the face of the frame, for better light block and shallow recesses). For an inside mount, measure the width at three heights and the height at three points, then use the narrowest width and the longest height. Give us the exact opening size — we apply the factory clearance deduction for you. For an outside mount, add 2–4" beyond each side and mount the headrail 3–6" above the frame.

  • Inside mount: measure the opening; take the narrowest width and the longest height; needs at least 2" of flat depth.
  • Outside mount: window width + 4–8" total; headrail 3–6" above the frame.
  • Rounding: width down to the nearest 1/8", length up to the nearest 1/8".
  • No fullness: shades hang flat — order the exact size, never a multiple like curtains.
  • Tools: use a steel tape measure; cloth tapes stretch and cause most misfits.
  • When to choose inside-mount window shades, recessed inside the frame

    Inside Mount Your Window Treatments When:

    • Enough window depth for inside mount (at least 2").
    • To get a sleek and minimalist aesthetic for your space.
    • The window trim is visually appealing and should be highlighted rather than concealed.
    • You prefer window treatments that blend seamlessly with the wall without protruding.
    • The windows have sturdy frames capable of supporting the mounting hardware.
    • The house is relatively new, with well-shaped rectangular windows.
    • The window sill extends outward, complicating the use of an outside mount.
  • When to choose outside-mount window shades, mounted on the wall

    Outside Mount Your Window Treatments When:

    • The window depth is not enough, also is irregularly shaped, unsuitable for an inside mount.
    • The objective is to cover unattractive window trim and refresh the window’s appearance.
    • Maximum light-blocking capability is required when the shades are drawn.
    • The window frame is too fragile or shallow to support an inside mount.
    • Privacy is a primary concern, and the shades need to block external view when closed.
    • The goal is to create the impression of taller, larger windows.
    • When rolled up, the window treatment should be as unobtrusive as possible.

Measure the Window for Inside Mount

How to measure a window for inside-mount shades: depth, width, and length
  • Depth: Measure inside casing depth at the top for inside or flush mount suitability. Depth needs vary by shade.
  • Width: Measure top, middle, and bottom; round down to the nearest 1/8 inch.
  • Length: Measure left, center, and right; round up to the nearest 1/8 inch, using the largest measurement.

Note on Deduction

  • Inside-mount deduction for cellular and Venetian shades: minus 1/4 inch width
  • Inside-mount deduction for Roman and bamboo shades: minus 3/8 inch width
  • Inside-mount deduction for roller and zebra shades: minus 1/4 inch width
1 3

Inside-Mount Deduction by Shade Type

Please apply the deduction yourself before ordering. Every shade is made to the exact width you submit — we do not adjust or subtract anything from the figures you enter. Use the guide below to work out your ordering width.

Shade Type

Width Deduction to Subtract Yourself (Inside Mount)

Height / Length

Cellular / Venetian Blinds

− 1/4"

No deduction

Roller / Zebra Shades

− 1/4"

No deduction

Roman / Bamboo Shades

− 3/8"

No deduction

Measure your window opening width, subtract the amount shown above, and enter that final figure as your order width. Height is ordered exactly as measured, with no deduction.

Please note: the figures above are the general standard for each shade family. The exact deduction can differ by product, so always follow the measuring instructions on the product page you are ordering from — that page takes precedence over this table.

Measure the Window for Outside Mount

How to measure a window for outside-mount shades: headrail width and length
  • Check Space: Measure the height above the window to ensure enough room for secure headrail and bracket installation.
  • Width: Measure the window's outer frame width. Add 2-4 inches total to reduce light gaps if space allows—this is your ordering width.
  • Length: Measure the window's outer frame height. Mount 10-12 inches above the frame, if possible, to account for stack height and maximize exposure.

How to Measure Odd-Shaped Windows & Shades

EaseEase shades for arched, angled, and triangular windows can’t use one straight measurement — capture the widest width, the tallest height, and any key angle or curve radius, then choose an inside or outside mount.

How to measure odd-shaped and arched windows for custom shades

Three Ways to Dress an Odd-Shaped Window

  • Custom Curtains — hung inside the arch, or from a track at the apex of a triangle window.
  • Honeycomb (Cellular) Shades — cut to the exact curve or angle, from sheer to full blackout.
  • Custom Shutters — built to the window’s exact shape for the strongest light control and privacy.
See Real Triangle & Arched Window Cases

Need help with your exact window?

Every odd-shaped window is unique. For exact measuring help or a made-to-measure template, reach our design team directly:

Text: +1 (689) 231-1581   |   Email: support@easeeasecurtains.com

Read the Full Odd-Shaped Windows Guide

Scope & What This Guide Does Not Cover

These instructions apply to standard rectangular windows measured in inches for custom (made-to-measure) roller, roman, cellular, zebra, bamboo and woven shades. They are not sizing rules for ready-made shades, and they do not apply to curtains — curtain width is calculated from the rod and multiplied for fullness, which is a different method (see How to Measure Curtains). For arched, skylight, corner/L-shaped, or extra-wide windows, follow our dedicated guides, and when in doubt use EaseEase’s Free Design Service.

Shade Measuring FAQ

What is the difference between inside and outside mount for shades?

Inside mount sits inside the frame for a sleek built-in look and needs at least ~2" of depth, while outside mount installs on the wall to maximize coverage and block light.

How much window depth do I need for an inside-mount shade?

You need at least 2 inches of flat, unobstructed depth inside the window recess for most roller and zebra shades, and about 3 inches for cellular and roman shades so the stack sits fully inside. Measure from the front edge of the frame back to the glass, and check for anything that eats into that space — handles, cranks, tilt latches, alarm sensors or deep trim.

If you have less depth than that, choose an outside mount instead. It mounts on the wall or on the face of the frame and works at any depth.

Why is my finished shade narrower than the window I measured?

That is intentional. An inside-mount shade needs clearance to raise and lower without scraping the frame, so the factory takes a small deduction — usually 1/4" to 1/2" off your stated width — before cutting.

Give us the exact opening size and do not subtract anything yourself. If you deduct as well, the shade ends up too narrow and light gaps appear on both sides. For an outside mount no deduction is applied — the shade is made at the width you order.

How should I round my shade measurements?

Work to the nearest 1/8 inch and never round to the nearest inch.

  • Width: round down to the nearest 1/8", so the shade always clears the frame.
  • Height: round up to the nearest 1/8", so the shade covers the opening completely.

Use a steel tape measure, not a cloth or plastic one — fabric tapes stretch, and that is the single most common cause of a shade that does not fit.

How much bigger should an outside-mount shade be than the window?

Add 2–4 inches beyond each side of the window opening (4–8 inches on the total width) and mount the headrail 3–6 inches above the frame. That overlap is what blocks the light which would otherwise leak around an inside-mount shade, so go to the wider end of the range for a bedroom or media room.

For length, measure from where the headrail will sit down to the point you want the shade to end — the sill, the apron, or the floor — and confirm you have flat wall to screw into above the frame.

How do I measure an arched, skylight or odd-shaped window for shades?

Standard width-and-height measuring does not work on these. Arched windows need the spring line and the radius; skylights need the recess measured at the glass plus the tilt angle; corner and bay windows need each section measured separately along with the angle where they meet.

Send us a photo with rough dimensions through our Free Design Service and we will produce a measuring sheet for your window. It is free, and far cheaper than a custom shade cut to the wrong shape.

EaseEase Curtain Tips & Tricks

View all
View all
1 4