Article: How to Measure for Levolor Blinds: A Step-by-Step Guide

Hands measuring window width with tape measure

Aug 17, 2026en

How to Measure for Levolor Blinds: A Step-by-Step Guide

Here’s the short version: for an inside mount, measure your window’s width in three spots (top, middle, bottom) and use the shortest number. Then measure height in three spots (left, middle, right) and use the longest number. Round everything to the nearest 1/8 inch. For an outside mount, you’re not measuring the opening at all. You’re measuring the full area you want covered, then adding a little overlap on the sides and top so light can’t sneak around the edges.

That’s the whole rule in a nutshell, and it’s the reason Levolor’s own measuring guidance and most reputable custom blind makers use nearly identical language. Windows are rarely perfectly square (yours probably isn’t either, and that’s fine), so this shortest width, longest height convention is what keeps your blind from binding on one side or leaving a gap on the other.

Before you grab your tape measure, here’s the cheat sheet to copy down:

Inside mount width: Measure top, middle, bottom. Record the smallest number.
Inside mount height: Measure left, middle, right. Record the largest number.
Outside mount: Measure your full desired coverage area, then add 2 to 4 inches per side (adjust for your light-blocking needs) and 3 to 4 inches at the top.
Tolerance: Round to the nearest 1/8 inch. Measure twice if anything looks off.
Label it: Always note “Inside Mount” or “Outside Mount” next to your numbers when you order.

Pro Tip: If your top, middle, and bottom width measurements differ by more than 1/4 inch, your window frame is out of square, which is extremely common in older homes. Don’t average the numbers. Use the exact smallest one, every time.

Key Takeaways

Accurate Levolor blind orders come down to one rule: measure three points per dimension, use the shortest width and longest height for inside mounts, and round to the nearest 1/8 inch every time.

Point	Details
Inside mount rule	Measure width and height three times each; record the shortest width and longest height.
Outside mount rule	Measure your full coverage area and report finished width and height, including overlap.
Check recess depth	Confirm headrail clearance before ordering, especially for wood or vertical blinds.
Label your order clearly	State Width × Height and mark it Inside Mount or Outside Mount, plus any obstruction notes.
Get professional help	Valueblindsdirect’s Design Studio and pro measure service handle tricky or out-of-square windows.

Where to Verify Product-Specific Measuring Details

Before placing a final order, it’s worth double-checking the specifics for your exact blind type:

How to Measure for Inside Mount Blinds for detailed width and height steps
How to Measure Outside Mount Blinds for overlap and coverage guidance
Measuring Windows for Blinds: The Simple Step-by-Step Guide for tools and common mistakes
The Window Treatment Design Studio for templates and guided measuring tools

If a window still doesn’t match anything you’ve read, reach out to customer support with your labeled measurements and a couple of clear photos. That combination gets you a faster, more accurate answer than a phone call alone ever could.

How to Measure for an Inside Mount
How to Measure for an Outside Mount
Do Different Levolor Blind Types Change How You Measure?
What About Cranks, Handles, Trim, and Odd-Shaped Windows?
What Should You Write Down When You Order?
Tools and Checklist to Get It Right the First Time
Where to Find Videos and Printable Measuring Templates
Expert Tips That Actually Prevent Fit Problems
Get Help Measuring, or Skip Straight to Ordering

How to Measure for an Inside Mount

The rule is simple: shortest width, longest height, measured to the nearest 1/8 inch. Inside mounts sit flush within the window frame, so precision here directly determines whether your Levolor blind slides in cleanly or fights the frame on installation day.

Grab a steel tape measure (a cloth or plastic one flexes too much for accurate readings) and follow these steps in order:

Measure width at the top. Place the tape inside the frame, from the inner edge of the left jamb to the inner edge of the right jamb. Hold it flat and level, without letting it sag in the middle.
Measure width in the middle. Repeat the same process halfway down the window.
Measure width at the bottom. Repeat again near the sill.
Compare all three width numbers and record the smallest one. This becomes your order width.
Measure height on the left side. From the top inside edge of the frame down to the sill, again holding the tape straight.
Measure height in the middle, then on the right side.
Compare the three height numbers and record the largest one. This becomes your order height.
Round every measurement to the nearest 1/8 inch. Don’t round to the nearest 1/4 or half inch. That small difference matters more than it seems once a headrail is involved.

Paint buildup, warped trim, and old caulk lines throw off more measurements than people expect. If your tape catches on a lump of paint at one measuring point, note it and measure again slightly above or below to get a true reading, then use the smaller number if there’s any doubt.

Pro Tip: Check your recess depth before you finalize your order, not after. Levolor blinds need a minimum amount of clear space inside the frame for the headrail to sit properly. A recess that’s too shallow (often under an inch, depending on the product’s headrail depth) will force you into an outside mount instead, so measure that depth at the same time you measure width and height.

Hand measuring window recess depth with ruler

If you’re at all unsure about a tricky frame, snap a photo straight on and another from the side showing the depth of the recess. Those two angles tell a support rep almost everything they need to troubleshoot a fit issue before it becomes a returned order.

How to Measure for an Outside Mount

Outside mounts flip the logic entirely: instead of fitting inside a fixed opening, you decide how much wall or trim you want the blind to cover, and you report that finished width and height directly.

Here’s how to get it right:

Decide your coverage area. Look at the window and picture exactly where you want the blind’s edges to land, factoring in how much light control and privacy you want.
Measure the full width you want covered, mounting bracket to mounting bracket, at the height where the headrail will sit.
Measure the full height you want covered, from where the top of the blind will mount down to where you want it to end (sill, apron, or floor).
Add your overlap. Outside mount measurements should always include a margin beyond the window opening itself, not just the opening’s raw dimensions.
Report the finished width and height, not the opening size. This is the number Levolor actually needs.

Overlap guidelines vary depending on how much light gap you’re willing to tolerate:

Minimal reveal (clean, modern look): 1.5 to 2 inches of overlap per side.
Standard light control: 2 to 3 inches of overlap per side, 3 to 4 inches at the top.
Blackout or maximum privacy: 3 to 4 inches of overlap per side, with extra top coverage to block light gaps near the headrail.

Say your window opening measures 36 inches wide by 60 inches tall, and you want standard light control. You’d add roughly 3 inches per side (6 inches total) for a finished width of 42 inches, and about 4 inches at the top for a finished height of 64 inches. Multiple windows side by side? Measure each one separately, but keep your mounting height consistent across the whole bank so the finished look reads as one continuous line rather than a staggered mess; for guidance on measuring multiple window openings, see High-Quality Doors and Windows for Your Log Cabin.

Yes, and this is the step homeowners skip most often. The basic width and height rules stay the same, but the depth requirements and what number the factory expects (cut size versus finished size) shift depending on which product you’re ordering. Vertical blinds in particular have their own headrail clearance needs that catch a lot of first-time buyers off guard.

Wood and faux-wood venetian blinds tend to need the most generous recess depth because the slat stack sits thicker at the top than a roller or cellular shade does. If your recess is shallow, an outside mount solves the depth problem entirely since there’s no frame constraint to work around.

Pro Tip: If you’re ordering blackout roller shades, add extra side overlap beyond what you’d use for a light-filtering shade of the same size. Blackout fabric doesn’t flex around light gaps the way sheer or light-filtering material does, so a snug fit that looks fine on a day shade can leave visible light lines on a blackout one.

Roller shade overlapping window frame edges

What About Cranks, Handles, Trim, and Odd-Shaped Windows?

Obstructions don’t mean you’re stuck. They just mean you need to measure around the problem instead of through it. The first decision is whether an obstruction rules out an inside mount altogether. If a crank handle, sash lock, or thick trim piece juts into your recess space, an outside mount often solves the problem without any workaround at all.

Here’s a quick obstruction checklist:

Window cranks or cams: Measure to the point where the crank protrudes furthest into the frame, not to the frame’s inner edge, and use that as your usable depth.
Handles or locks: Note their exact position so the installer (or you) can plan bracket placement that clears them.
Thick or uneven trim: Measure at multiple points around the obstruction and use the most conservative (safest) number.
Multiple window banks: Measure each opening independently, but keep mounting height uniform across the whole run for a clean, continuous line.

Arched and angled windows are their own category. For those, you’ll typically need to supply a template or a detailed sketch with multiple measurement points along the curve, since a single width and height number can’t describe an arch. Custom arched headrails exist for exactly this reason, and ordering one usually means working directly with a specialist rather than a standard online configurator.

Pro Tip: If you’re dealing with more than one obstruction, a bay window, or a frame that’s visibly out of square by more than half an inch, that’s your cue to consider professional measuring instead of pushing through it solo. A pro visit costs far less than a custom blind that doesn’t fit.

What Should You Write Down When You Order?

Give exactly one format: Width × Height, followed by a clear label of Inside Mount or Outside Mount. That’s it. Everything else is supporting detail.

A properly labeled measurement looks like this:

Living room window: 35 5/8" W x 60 1/4" H — INSIDE MOUNT
Kitchen window: 42" W x 64" H — OUTSIDE MOUNT, 3" side overlap, 4" top overlap
Bedroom window: 24" W x 48" H — INSIDE MOUNT, note: crank handle protrudes 1.25" into recess

Here’s the important part most first-timers don’t realize: for inside mounts, the factory typically deducts a small amount from your reported width automatically to allow the blind to operate smoothly inside the frame. That means you should report your exact measured width, not a width you’ve already shrunk to “leave room.” Let the manufacturer handle that adjustment. Double-deducting is one of the fastest ways to end up with a blind that’s noticeably too narrow.

When you submit your order, include notes about anything unusual: obstructions, bracket placement preferences, or desired overlap amounts for outside mounts. A support team can’t guess what your window looks like, but a clear note like “crank protrudes 1.25 inches” or “outside mount, want 3-inch side overlap for blackout” tells them everything they need in one line.

Tools and Checklist to Get It Right the First Time

A tape measure is a tape measure, right? Not quite. A steel tape holds its shape and gives you a straight, accurate line across a window opening, while a cloth or fabric tape sags and introduces small errors that add up fast, especially on wider windows. Here’s your full measuring toolkit:

Steel tape measure (at least 12 feet for larger openings)
Pencil and paper (or notes app) to record each of your six measurement points
A small level to confirm your headrail line will sit straight
A sturdy ladder for taller windows, so you’re not stretching or guessing
Your phone camera to photograph tricky spots for reference or support

The most common mistakes are almost all avoidable:

Measuring only once instead of at three points per dimension
Rounding to the nearest 1/4 or 1/2 inch instead of the required 1/8 inch
Skipping the recess depth check entirely
Forgetting to account for trim, handles, or crank protrusions
Averaging measurements instead of picking the smallest width or largest height

If you photograph your window for reference or to share with support, take one straight-on shot of the full window, one close-up of any obstruction, and one angled shot showing recess depth. Label each photo with the room name so nothing gets mixed up.

Quick onsite checklist:

Measure width (top, middle, bottom) — record smallest
Measure height (left, middle, right) — record largest
Check recess depth
Note any obstructions
Label inside or outside mount

Where to Find Videos and Printable Measuring Templates

You don’t have to work from memory or guesswork. Printable worksheets and video walkthroughs exist for exactly this reason, and using one while you measure cuts down on transcription errors between your notepad and your final order.

Resource Type	What It Includes	Best Used For
Video demos	Visual walkthrough of tape placement and technique	First-time measurers, visual learners
Printable worksheet	Pre-labeled fields for width, height, mount type, notes	Recording measurements onsite, room by room
Photo-attachment template	Structured format for pairing photos with numbers	Sharing with support, verifying tricky windows

When you use a printable worksheet, fill in every field even if it seems obvious, room name, mount type, all three width readings, all three height readings, and recess depth. That redundancy is exactly what lets a support rep spot an inconsistency (like a width that doesn’t match your recess depth) before your order ships instead of after it arrives.

Expert Tips That Actually Prevent Fit Problems

A few habits separate a first-time-right order from a return shipment. Out-of-square frames trip up more homeowners than any other single issue, and the fix isn’t complicated: always trust your smallest width and largest height readings over any single “convenient” measurement, even if the difference feels tiny.

Order slightly extra width across a continuous bank of windows so the blinds visually line up rather than showing gaps between panels.
Keep mounting height identical across multiple windows in the same room, even if the windows themselves are slightly different sizes.
For motorized Levolor options, confirm you’ve left clearance for the motor housing, which typically adds a bit more depth than a manual headrail.
Re-measure any window that’s been recently repainted or re-trimmed, since even a fraction of an inch of new material changes your numbers.

If your windows are heavily out of square, part of a large bay configuration, or involve structural quirks you’re not confident measuring around, professional measure and installation exists precisely for that scenario. It costs more than DIY measuring, but it costs a lot less than reordering a custom blind that never should have shipped in the first place.

A Few Honest Words on Getting This Right

Most measuring mistakes I see aren’t from careless people. They’re from careful people who measured once, trusted that single number, and moved on. The three-point method feels redundant until the day it saves your order, and it will, because almost no window in a real house is perfectly square. If you take one thing from this guide, let it be this: measure three times, record all three, and never average them away.

If a window still stumps you after following every step here, that’s not a failure on your part. Some frames are genuinely tricky, and that’s exactly what measuring help and support exist for.

Get Help Measuring, or Skip Straight to Ordering

Not everyone wants to climb a ladder with a steel tape and cross their fingers, and that’s completely fair. Valueblindsdirect gives you two paths depending on how hands-on you want to be: use the free Design Studio to walk through measurements with guided tools and templates, or opt for a professional measure and installation if your windows are tricky, out of square, or part of a large multi-window project.

Valueblindsdirect

The Design Studio standardizes your measurement labels automatically, lets you attach photos of obstructions or odd angles, and flags inconsistencies before your order ever gets placed, which is exactly the kind of safety net that turns a shaky first-time measurement into a confident one. If you’d rather hand the whole process off, professional measuring removes the guesswork entirely, especially valuable for bay windows, heavily obstructed frames, or homes with a lot of window banks to keep visually consistent. Ready to move forward? Head to the blinds collection to browse styles once your measurements are locked in, or start in the Design Studio to get guided support from the first measurement to the final order.