When it comes to window treatments, blinds are one of the most popular options for many homeowners. They provide privacy and light control and come in various styles, colors, and sizes to fit any window. However, with so many size options, figuring out what size blinds you need for your windows can be confusing.
This comprehensive guide will walk you through how to measure your windows correctly and use a window blind size chart to find the right fit. We’ll also cover standard blind sizes and widths, recommendations for different window types, and tips for getting an accurate measurement.
How To Measure Windows For Blinds
The first step is accurately measuring your window openings. This will allow you to use a window blind size chart to find the closest fit. Here’s how to measure for the inside mount (fits within window framing) and outside mount (mounts outside framing):
Inside Mount
- Measure the width from inside edge to inside edge across the window frame’s top, middle, and bottom. Use the narrowest width.
- For height, measure from the top inside edge of the frame to the window sill.
- Note the depth of your window frame to ensure the blind fits flush within it.
Outside Mount
- Measure the width from outside edge to outside edge across the window frame’s top, middle, and bottom. Use the widest width.
- For height, measure from above the window frame to where you want the blinds to end. Add 3-4 inches if you want them to cover part of the wall.
- There is no need to measure depth for an outside mount.
Tip: Always take width measurements in three places as windows can be out of square. Use the smallest width to allow blinds to fit. For height, decide if you want blinds to cover the window or part of the wall.
Window Blind Size Chart
| Blind Width | Fits Window Width |
| 16 inches | 14 – 16 inches |
| 20 inches | 18 – 20 inches |
| 24 inches | 22 – 24 inches |
| 28 inches | 26 – 28 inches |
| 30 inches | 28 – 30 inches |
| 32 inches | 30 – 32 inches |
| 34 inches | 32 – 34 inches |
| 36 inches | 34 – 36 inches |
| 40 inches | 38 – 40 inches |
| 44 inches | 42 – 44 inches |
| 48 inches | 46 – 48 inches |
| 52 inches | 50 – 52 inches |
| 56 inches | 54 – 56 inches |
| 60 inches | 58 – 60 inches |
| 64 inches | 62 – 64 inches |
| 72 inches | 70 – 72 inches |
- Measure the window width at the top, middle, and bottom. Use the smallest width.
- Choose the next size up from your tightest measurement.
- Add 2-4 inches to width if mounting blinds outside the window frame.
- For custom in-between sizes, choose cut-to-width blinds.
How To Use A Window Blind Size Chart
Once you have accurate window measurements, it’s time to use a window blind size chart. Here are some tips:
- Look at the width ranges on the chart and choose the next size up from your tightest window width. For example, if you measured 25.5 inches wide, choose 26-inch blinds.
- Again, choose the next size up from your measurement for height to allow clearance. If you measured 48 inches, go with a 48-inch or 50-inch height blind.
- Look for a “cut-to-width” option if your measurements fall between standard sizes. This allows blinds to be customized to the exact width needed.
- Consider getting blinds slightly wider than windows to stack fully open on both sides. An extra 2-4 inches is ideal.
- Verify that specified sizes are for the blind slats, not including valances or brackets. This ensures you get the right interior coverage.
- Please check the minimum and maximum sizes listed for blind types, as some don’t work for very small or large windows.
Following these tips will make using a size chart easy and ensure your new blinds fit perfectly.
Standard Window Blind Widths
Window blind size charts typically show a range of joint widths. Here are the most standard vertical blind widths available:
- 16 inches
- 20 inches
- 24 inches
- 28 inches
- 30 inches
- 32 inches
- 34 inches
- 36 inches
- 48 inches
- 72 inches
Widths between 34 and 72 inches tend to increase in increments of 4 inches (34, 38, 42, 46, etc.). Custom odd widths are also possible when using cut-to-width blinds.
The average window size is 30 x 60 inches, so many manufacturers frequently stock blinds around these dimensions. However, specialty stores will carry additional sizes for larger or smaller windows.
How Wide Is a 35-Inch Blind?
When looking at blind sizes, it helps to visualize precisely how wide joint widths will be when installed:
- Sixteen inches: Perfect for small bathroom windows, sidelights, or corner windows. Provides minimal light control.
- Twenty-four inches: Ideal for small to medium windows or sidelights. Fits most standard single sash windows.
- Thirty inches: The most common width fitting average double-hung windows. Allows for full coverage.
- Thirty-six inches: Provides full light control on larger windows and sliding glass doors. Stacked blinds will cover about 18 inches on each side when fully opened.
- Thirty-five inches specifically: This odd size falls between two standard widths of 34 and 36 inches. It will span on the broader side of average windows. Stacked 35-inch blinds will cover about 17.5 inches on each side when opened.
In summary, a 35-inch blind is well-suited for large single or small double-hung windows approximately 35 inches wide. It will provide complete light coverage with a little extra stacking room.
What Size Blinds for 34.5 Inch Window?
When your window measurements don’t align with standard blind sizes, you have a couple of options:
- Size up to the next common width and cut the blinds down to fit exactly. For a 34.5-inch window, go with 36-inch blinds and trim them to 34.5 inches wide.
- Choose a custom cut-to-width option. The manufacturer will make blinds precisely to your needed width of 34.5 inches.
- Install overlapped blinds. You could install two 17-inch blinds side-by-side to span the 34.5 inches across.
The easiest option is to go up to the next full size and trim down. Just make sure to measure carefully so the blinds aren’t too narrow. Getting custom or overlapped blinds requires more precision but gives an exact fit.
Tip: Add an extra 1/4 inch if sizing up and cutting down blinds yourself. This prevents any gaps if your DIY cutting isn’t 100% perfect.
Most Popular Residential Blind Sizes
While commercial buildings often need larger custom blinds, there are a few standard sizes that work well for most homes:
- Twenty-four inches wide: This size fits smaller windows, such as those in bathrooms and kitchens. It can also cover single or narrow double-hung windows.
- Thirty inches wide: This is ideal for the average double-hung window, which is 30 x 60 inches. It provides full light control.
- 36 inches wide: This width accommodates larger slider windows and patio doors. It is wider to allow for complete coverage and stacks back fully open on each side.
- 48 – 72 inches wide: For big living rooms, picture windows, wide sliding doors, and commercial settings. Useful for large expansive windows.
- 60 – 72 inches long: Typical lengths to cover standard window heights. Allows blinds to stack neatly while thoroughly covering the window.
These popular residential widths cover most standard window sizes. But don’t be afraid to go custom if your windows are an odd shape or size.
Blind Size Recommendations By Window Type
Beyond basic width and height, selecting the proper blind depends on your specific window type. Here are blind measurement tips for standard windows:
Double Hung Windows
- Inside-mount double-hung blinds are 1 inch narrower than the window frame. This allows them to clear the sash tracks when raised.
- Outside-mount blinds should be 2 inches wider than the frame to clear handles and trim. If covering the wall, add more width, too.
- For height, inside mounts should match the frame. Outside mounts can extend above the frame 4-6 inches to cover the wall.
Sliding Glass Doors
- Mount blinds outside the frame for minimal light gaps. Make them at least 2 inches wider than the door.
- Extend blinds past the height of the door frame if you want to cover the adjacent wall.
- Consider extending the width to 144 inches or more for wide slider doors.
Arched Windows
- Measure the widths at the arch’s base, middle, and top. Use the smallest width.
- For height, measure from the bottom of the base up to the ceiling or where you want the blinds to end.
- Look for arched blind hardware designed specifically for curved windows. Or install multiple standard rectangular blinds.
Skylights
- Use the rough opening size as your width and height measurements.
- Blackout blinds or dual shades work well to darken skylights when needed.
- For hard-to-reach skylights, look for remote control options to operate blinds efficiently.
Bay Windows
- Take three width measurements: the left window, the middle window, and the right window. Size the blinds to the smallest width.
- Get three blinds, one sized for each window section rather than spanning the whole bay.
- If you want total light control, make sure the combined width of all three blinds covers the entire bay with no gaps.
Getting the proper blind measurements for your window type is critical. Consult with a window professional if unsure.
Tips For Accurate Blind Size Measurements
To select a properly fitting blind, you need exact measurements. Here are some tips for ensuring accuracy:
- Always measure to the nearest 1/8 inch rather than rounding off. Small fractions matter for an ideal blind fit.
- Use a steel tape measure instead of a cloth that can stretch and provide incorrect sizes. Make sure the tape measure is entirely straight and tight across the window.
- Have two people measure together – one to do the measuring and one to double-check and confirm the numbers. Four eyes are better than two!
- Measure all windows even if they look the same size. Windows in older homes especially can have slight variations.
- Measure in three spots for both width and height. Some windows bow in or out, so you need the smallest and largest numbers.
- For outside mounts, measure where you want the blinds to end below the window. Add about 3 inches if covering just the wall or 6 inches if extending further down.
- If doing an inside mount, note the window depth to choose a blind that fits flush within the frame.
- Take pictures of your window sizes written down at each window. This prevents you from losing measurements if you record them elsewhere.
- Measure the light conditions at the same time of day when blinds are used. Heat can cause window sizes to vary slightly.
Accurate measurements are genuinely vital. If blinds turn out too small, light will leak around the edges. They are too big and won’t fit the window or operate properly. Taking the time to measure correctly makes a big difference in getting a perfect blind fit.
How Are Blind Widths Calculated?
Blind width calculations determine the size of blinds based on your window measurements and mounting preferences. Here is an overview of how width is calculated:
Inside Mount Width
For inside mounts, calculate the width as:
- Window Frame Width
- Minus 1/4″ – 1/2″ clearance
- Equals Blind Width
So, if your window frame is 36″, you would get 35 1/2″ blinds to allow a little room between the blind and frame edges.
Outside Mount Width
For outside mounts, calculate the width as:
- Window Frame Width
- Plus, 1″ – 3″ overlap beyond the frame for optimal light-blocking
- Equals Blind Width
So, for a 30″ window, you may get 33″ blinds mounted outside the frame for full light control.
Cut-To-Width
For sizing between standard widths, calculate as:
- Precise Window Opening Width
- Plus 1/4″ – 1/2″ clearance
- Equals Cut-To-Width Blind Size
So, for a 34 1/2″ opening, cut-to-width blinds would be made at 34 3/4″ wide.
The mounting method and desired light blocking are the main factors in choosing the ideal blind width. Calculating based on window measurements ensures the proper fit and function.
Do Wide Blinds Need Center Support Brackets?
You may wonder if center support brackets are needed for larger windows requiring wide blinds. Here are some tips:
- Blinds up to 36 inches wide typically don’t need center support.
- Blinds that are 36-48 inches wide should have a center support bracket to stabilize and prevent sagging.
- Blinds 48-72 inches wide require two or more center support brackets evenly spaced across the width.
- Blinds 72 inches and over may also need additional rigidity strengthening in the top headrail or mid-rail.
Wide blinds exert more gravitational force on the headrail and slats, so strategic center brackets prevent drooping. Follow the manufacturer’s recommendations for the maximum spacing between brackets. Proper installation is critical to keeping large blinds straight and level.
How Much Do Blinds Cost?
Blind prices can vary widely depending on the size, material, unique features and whether custom or standard:
- Aluminum blinds: $3 – $25 per blind
- Wood & faux wood blinds: $10 – $75 per blind
- Vinyl blinds: $5 – $30 per blind
- Vertical blinds: $20 – $80 per blind
- Cellular shades: $15 – $100 per blind
- Blackout shades: $25 – $150 per blind
- Custom sizes: Add $5 – $20 per blind upcharge
Less expensive vinyl and aluminum are the most budget-friendly. Wood blinds, custom sizes, and extra features like motorization quickly increase costs. Cellular and blackout shades also cost more due to their layered construction.
Get free quotes from multiple retailers to find the best pricing. Look for sales around holidays for significant discounts, too. With some shopping, attractive and affordable blinds can fit almost any budget!
Conclusion
Choosing the perfect window blind size may seem tricky. But armed with accurate window measurements and tips in this guide, you can easily select custom or standard-sized blinds that fit beautifully and function as needed. Use steel tape, double-check widths and heights, and allow extra room for ideal light blocking. Follow any particular measurement recommendations for your window type, too. With suitable blind sizes, you’ll enjoy years of privacy, UV protection, and style. Don’t hesitate to enlist the help of a professional if you are unsure about getting measurements right. Taking the time to get blinds sized correctly results in sharp windows that maximize your decor.
FAQs
How do I measure for blinds if I have trim or molding around the window?
For outside mounts over trim, measure from the outer edge of the trim to the outer edge on the opposite side. For inside mounts, measure the inner opening size, then deduct any trim depth.
Should I get blinds wider than the window?
Making blinds 2-4 inches wider than windows for outside mounts is recommended. This ensures complete light blockage and allows blinds to stack back fully open on each side.
What if I don’t see my exact measurements on a size chart?
You can order custom cut-to-width blinds made precisely to your needed width and height. Or size up to the next closest standard size and trim down.
Do I measure just the glass for window blinds?
No, you’ll measure the entire window opening or frame. The blind needs to cover the whole window area, not just the glass pane.
How do I measure if my windows are arched or round?
Measure the width of arched windows at the base, middle, and top. Use the smallest width. For round windows, measure the diameter across the center and order a rectangular blind to mount.
