Not every mattress fits a size chart. Antique bed frames, RV bunks, boat berths, a topper that pushes your depth past standard, or a bed that's simply a couple inches off from Twin, Full, or Queen - if any of that sounds familiar, a custom fitted sheet is the fix. Here's exactly how custom sizing works, what it costs, and what happens between the moment you order and the sheet showing up on your bed.
Who actually needs a custom fitted sheet
Standard sizing covers most beds, but plenty of real mattresses fall outside it. A few common cases:
- An antique or vintage bed frame built to dimensions that predate modern mattress standards
- A daybed, trundle, or built-in bunk that's a few inches narrower or longer than Twin
- A thick mattress topper that pushes your total depth past what a standard deep-pocket sheet covers
- A mattress that's simply between sizes, not quite Full, not quite Queen
- Specialty setups like RVs, boats, or campers with a bed shape a standard chart was never designed for
If your mattress fits a standard chart, a standard fitted sheet will cost less and ship faster. Custom is for when it genuinely doesn't.
How to measure before you order
Three numbers matter, and getting them right the first time saves a remake later.
- Width and length. Measure the bare mattress top, edge to edge, in both directions. Round to the nearest half inch.
- Pocket depth. Measure straight down from the top surface to where the mattress meets the frame or platform, then add the height of any topper or pad you sleep on. This is the single most common mistake, guessing at depth instead of measuring with the topper already in place.
- Double check on a bare mattress. Strip any existing sheet before measuring so you're working from the mattress itself, not a rounded estimate over fabric.
What happens after you order
Once you submit your measurements, the sheet isn't pulled off a shelf, it's cut and stitched specifically for your bed. SGI makes each custom fitted sheet at its own factory, cut and sewn by hand to your exact dimensions with no middleman reselling a generic product. That's part of why custom sizing takes a bit longer to ship than a standard in-stock sheet, you're waiting on a piece that's being made for your bed specifically, not picked from inventory.
The same deep pocket and elastic you'd expect from a standard sheet
Going custom doesn't mean giving up the details that keep a fitted sheet on the bed. SGI's custom fitted sheet still comes with a deep pocket built to your stated depth and 360-degree all-around elastic running the full perimeter, not just the corners. That combination is what keeps any fitted sheet, standard or custom, from sliding off overnight, and it matters even more on an odd-shaped mattress where a poor-fitting sheet has nothing standard to fall back on.
The 100% Fit Guarantee
Ordering a sheet you can't try on first is naturally a little nerve-wracking, which is exactly what the guarantee is for. SGI backs every custom fitted sheet with a 100% Fit Guarantee: if it doesn't fit your mattress once it arrives, they remake it. That takes the biggest risk out of buying something built to measurements rather than a size you could hold up in a store first.
600 Thread Count Custom Fitted Sheet
- Cut and sewn to your exact measurements
- Deep pocket + 360-degree all-around elastic
- 3-piece: fitted sheet + 2 envelope pillowcases
- 100% Fit Guarantee, remade if it doesn't fit
From $64.99
Shop custom fitted sheetsFabric and colors
The custom fitted sheet is woven from long-staple 600 thread count cotton, the same everyday-luxury fabric used across SGI's standard sheets, breathable and smooth without the maintenance a delicate fabric would need. It comes in 8 colors: White, Light Grey, Dark Grey, Butter, Taupe, Navy Blue, Burgundy, and Moss, so custom sizing doesn't mean settling for whatever's left over, you still get a full color range to match your room.
If it's a whole set you need, not just the fitted sheet
This guide focuses on the fitted sheet specifically, since that's the piece where an odd mattress causes the most trouble. If you need the flat sheet and pillowcases custom-cut too, not just the fitted piece, our custom size sheets guide covers the full set version and how that ordering process works.
Care instructions
Machine wash in cool or warm water and tumble dry on low. The cotton is fade-resistant and built to hold its softness wash after wash, custom sizing doesn't change how the fabric behaves in the laundry, just how it's cut.
A few common questions
How long does a custom fitted sheet take to arrive?
Longer than an in-stock standard sheet, since it's cut and sewn specifically for your measurements after you order rather than pulled from inventory. Check the product page for current production timelines before ordering if timing matters.
What if I measure wrong and it doesn't fit?
SGI's 100% Fit Guarantee covers this. If the sheet doesn't fit your mattress once it arrives, they remake it, so a measuring mistake isn't the end of the order.
Does a custom fitted sheet still have deep pockets and elastic?
Yes. The pocket depth is built to whatever measurement you provide, and it still uses 360-degree all-around elastic, the same construction that keeps a standard fitted sheet in place.
Do I need to order a custom sheet if my mattress is close to a standard size?
If your mattress is genuinely within a standard size chart, a standard fitted sheet will fit fine and cost less. Custom sizing is worth it once your mattress is even a couple inches outside every standard option.
A FITTED SHEET MADE FOR YOUR BED, NOT A CHART
Cut and sewn to your exact measurements, deep pockets, 360-degree elastic. Take 10% off your first order with code SGIFIRST10.
Shop custom fitted sheets
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