Can I Measure My Own Windows for Shutters and Shades? What Goes Wrong, and Who Pays

You can measure your own windows, and plenty of people do it well enough to get a real quote. But custom window treatments are cut to your numbers and cannot be returned, so if a shutter panel or a roller shade is built to a measurement that turns out to be wrong, the remake is charged to you at our invoiced cost with no markup — we do not absorb it.

Why the windows around here are harder to measure than they look

Most of the openings we see across the San Fernando Valley and Conejo Valley fall into two groups, and both cause trouble for a homeowner with a tape measure.

The first group is the 1950s through 1970s ranch stock in Northridge, Granada Hills, Chatsworth, Encino, and North Hollywood. Wide, low aluminum-frame windows, stucco openings that have moved with sixty years of soil, and retrofit vinyl inserts added in the 1990s and 2000s that shrink the usable jamb depth without anyone writing it down. Out-of-square is normal, not rare.

The second group is the newer hillside and gated stock — The Oaks in Calabasas, Hidden Hills, Bell Canyon, the Porter Ranch hillside tracts, parts of Woodland Hills and Agoura Hills. Cleaner framing, but two-story great room windows, tall view walls, and bullnose drywall corners instead of square wood jambs. Bullnose is the quiet killer: there is no flat interior surface to mount to, so an "inside mount" that measures fine on paper has nothing to screw into.

Then there is Toluca Lake and Studio City, where a lot of the housing is original 1940s casement and steel-frame sash with cranks, and Sherman Oaks and Tarzana, where nearly every back wall is a slider with a lock handle sticking into the opening.

None of that means you can't measure. It means the tape measure is the easy part, and the decisions around it are where jobs go sideways.

The six mistakes that actually cause remakes

1. Not stating inside mount or outside mount

This is the most expensive mistake because it is invisible until the box arrives. A factory building an inside-mount roller shade takes a deduction off your number — commonly somewhere between 1/4 inch and 1/2 inch total depending on the system — so the shade clears the jamb. A factory building an outside mount builds to your number exactly, because you already added overlap.

Send an outside-mount width labeled inside mount and the shade arrives short with light gaps down both sides. Send an inside-mount width labeled outside mount and you lose the coverage you wanted. Either way the fabric is cut.

2. Measuring width once

Measure the width at the top, the middle, and the bottom. Measure the height at the left, the center, and the right. On a 1960s Encino ranch it is routine to find 36 1/4 inches at the head and 36 inches at the sill on the same opening. For an inside-mount shade you use the narrowest width, because a product built to the widest number will not go in.

3. Assuming the opening is square

Run a diagonal both ways. If the two diagonals differ by more than about 1/4 inch, the opening is racked, and that changes the product recommendation, not just the number. A shutter frame can hide a surprising amount of out-of-square because the frame is installed plumb and the gap is shimmed and caulked behind it. A roller or cellular shade cannot hide any of it — the bottom rail hangs level while the sill does not, and you get a wedge of light that gets wider every year you look at it.

4. Ignoring what sticks into the opening

Casement cranks, slider lock handles, alarm contacts, tile returns, window film edges, and security screen frames all live inside the measurement. A shutter with a 3 1/2 inch louver needs clearance to swing and rotate; a crank handle that protrudes 1 1/4 inches means either a build-out frame, a cutout, or an outside mount. Homeowners measure the opening correctly and then discover the product will not close.

5. Rounding, and converting to decimals

Write 30 1/2 inches, not 30.5, and never round up. Custom factories work in 1/8 inch increments and they build what you send. A true 30 5/8 inches reported as 30 3/4 inches is 1/8 inch of interference on an inside mount, which on a tight vinyl retrofit jamb is the difference between fitting and not. When in doubt, round down and note it.

6. Forgetting depth

Width and height get all the attention; depth causes most of the "it sticks out" complaints. An inside-mount roller shade needs room for the tube and any cassette or fascia. A larger-diameter tube on a wide slider needs more. Inside-mount shutters need enough depth for the frame and the louver to rotate without hitting the glass or a retrofit flange. Plenty of Valley retrofit windows leave 1 1/2 inches or less of flat jamb, which often pushes the job to an outside mount or a build-out — a design decision that should be made before the order, not after.

One more practical note: a second-story great room window measured from the top of a ladder, alone, is not worth the savings.

Who pays when a custom product is built to a wrong number

We will say this plainly, because it is the part most companies bury.

If you supply the measurements and we order to them, those are your numbers. If the product comes back the wrong size because of that measurement, 818 Shutters & Shades charges you the remake at our invoiced cost from the factory, with no markup added. We do not mark it up, and we do not eat it. A shutter panel or a cut-to-size shade has no resale value and cannot be returned to the manufacturer, so someone is paying for that fabric and that frame.

If we measure the window, the risk is ours. A window on our measure sheet that comes out wrong gets fixed at our cost, not yours. That is the actual trade: a professional measure is not just a service, it is where the liability sits.

The same logic runs through most of what goes wrong on window treatment jobs. We wrote up the recurring patterns in the eight things that actually go wrong, and measurement errors are near the top of the list every time.

When sending your own numbers is genuinely fine

Self-measuring is the right call in three situations.

• Budgeting. You want to know whether a project is a $6,000 conversation or a $20,000 one before anyone comes to the house. Rough numbers are plenty.
• Remote quotes. Send sizes and photos and we will price the job. Nothing gets ordered off those numbers without a confirming measure, and that is intentional.
• Checking someone else's bid. Upload a competitor quote to Quote Check and we will read the line items against what the product actually is. If you want the framework first, start with how to compare quotes line by line.

Where self-measuring is not fine is the order itself. Once the factory cuts, the numbers are permanent.

What a professional measure covers that a tape measure doesn't

The measure appointment is doing four jobs at once: recording width, height, and depth at multiple points; checking square and plumb; identifying obstructions and mounting surfaces; and confirming that the product you picked is the right product for that specific opening. That last one matters most on west-facing glass, where the heat question and the fit question interact — see how shutters actually perform on afternoon heat.

When you're ready, someone comes to the home, measures every window, brings real samples you can hold against your own light, and you get a firm quote with installation included — not an estimate that moves later. The in-home consultation is free. Book a measure and we will take the measurement risk off your side of the ledger.

Frequently asked questions

Can I just send my own measurements and have you order from them?

You can, and we'll price the job from them. But we confirm sizes with a measure before anything is cut, because custom products can't be returned. If you insist on ordering from your own numbers and the product comes out wrong, the remake is charged to you at our invoiced cost from the factory with no markup.

How do I measure a window for inside-mount blinds or shades?

Measure the width at the top, middle, and bottom of the opening and use the narrowest number. Measure the height at the left, center, and right. Measure the flat jamb depth. Write everything in eighths — 30 1/2 inches, not 30.5 — round down rather than up, and label the order clearly as inside mount so the factory applies its deduction.

What if my window opening isn't square?

Check both diagonals. If they differ by more than about 1/4 inch, the opening is racked. Shutter frames can conceal a fair amount of that because they're installed plumb and shimmed behind the frame. Roller, cellular, and roman shades cannot — the bottom rail hangs level against an unlevel sill and you get a visible wedge of light.

Do I need a certain jamb depth for inside-mount shutters?

Yes. Inside-mount shutters need enough flat depth for the frame plus clearance for the louver to rotate without striking the glass or a retrofit window flange, and roller shades need room for the tube and any cassette. Many retrofit vinyl windows in Valley homes leave an inch and a half or less, which often means an outside mount or a build-out frame. That's a decision to make before ordering.

Is the in-home consultation free?

Yes. You get every window measured, real samples in your own light, and a firm quote with installation included in the price.