How to Measure Your Mattress Correctly for Custom Bed Sheets

Buying standard bed sheets is easy — you pick a size (Twin, Queen, King) off the shelf and hope for the best. But if your mattress is unusually thick, deep, oddly shaped, or simply doesn’t match “standard” dimensions anymore, off-the-shelf sheets almost never fit right. They ride up, slip off the corners, or bunch awkwardly in the middle of the night.

This is exactly why custom bed sheets exist — and why getting your measurements right is the single most important step in the process. A perfectly tailored fitted sheet is only as good as the numbers you give the manufacturer. Below is a simple, accurate way to measure your mattress at home, no professional tools required.

How to Measure Your Mattress for Custom Bed Sheets

Before ordering custom bed sheets, it’s essential to measure your mattress accurately. Record the length, width, and thickness (depth) in inches or centimetres, including any mattress topper. Even a difference of a few inches can affect how well your fitted sheet stays in place. Accurate measurements ensure your custom bedding fits perfectly without slipping or bunching.

What Are Deep Pocket Fitted Sheets?

Deep pocket fitted sheets are specially designed for mattresses that are thicker than standard sizes, typically ranging from 12 to 20 inches in depth. They feature extra-deep corners and stronger elastic to wrap securely around pillow-top, memory foam, and luxury mattresses, ensuring the sheet stays firmly in place throughout the night.

Mattress Sizes Explained: India vs US vs UK

Mattress sizes vary significantly between countries, which is why standard bed sheets don’t always fit imported or custom mattresses. A King or Queen mattress in India may have different dimensions from those in the US or UK. Understanding these size differences is essential when purchasing bedding, especially if you own an international or bespoke mattress.

Cotton vs Linen Bed Sheets

Cotton and linen are both premium natural fabrics, but they offer different sleeping experiences. Cotton is soft, breathable, easy to maintain, and suitable for year-round use, while linen is known for its textured feel, exceptional airflow, and durability. Choosing between them depends on your comfort preferences, climate, and desired bedroom aesthetic.

What Is the Best Thread Count for Bed Sheets?

The ideal thread count depends on the fabric and weave rather than simply choosing the highest number. For premium 100% cotton bedding, 300–500 thread count offers an excellent balance of softness, breathability, and durability, while higher thread counts such as 600–1000 TC provide a smoother, more luxurious feel when made with high-quality cotton.

Fitted Sheets vs Flat Sheets

A fitted sheet is designed with elasticated corners to hug the mattress securely, while a flat sheet is a rectangular sheet used as a top layer or tucked beneath the mattress. Both serve different purposes, and choosing the right option depends on your sleeping style, mattress type, and bedding preferences.

Common Mistakes When Buying Bed Sheets

Many people choose bed sheets based only on mattress width and length, overlooking important factors such as mattress depth, fabric quality, weave, and thread count. Buying the wrong size or focusing only on thread count often results in poorly fitting sheets, reduced comfort, and a shorter product lifespan.

How Custom Bed Sheets Are Manufactured

Unlike mass-produced bedding, custom bed sheets are made according to your mattress’s exact dimensions, including width, length, and depth. From fabric selection and cutting to stitching, elastic fitting, and quality inspection, every step is tailored to create bedding that fits your mattress perfectly while delivering superior comfort, durability, and a premium finish.

Why Mattress Measurements Matter So Much

Mattresses today aren’t as standardized as they used to be. Memory foam, hybrid, and pillow-top mattresses can range anywhere from 8 to over 18 inches thick. Add a mattress topper, and the depth changes again. A fitted sheet cut for a “standard” 9-inch pocket simply won’t stretch over a 15-inch memory foam mattress — and if it’s too deep, it will bunch and shift instead of sitting snug.

Custom bed sheet makers ask for three core measurements: length, width, and thickness (pocket depth). Getting each one right ensures the elastic hem sits exactly where it should, hugging the corners without slipping.

What You’ll Need

• A soft measuring tape (fabric or flexible tape works best)
• A helper (optional, but makes corner measurements easier)
• A notepad or your phone to record numbers

Step 1: Measure the Length and Width

Strip your mattress down to the bare surface. Measure from edge to edge:

• Length — from the top of the mattress to the bottom, running along the longest side.
• Width — from left to right, across the shorter side.

Take each measurement twice, at slightly different points along the edge, since mattresses can bow or taper slightly. Use the largest number you record — it’s always safer to round up a fraction of an inch than to end up with a sheet that’s too tight.

Step 2: Measure the Thickness (Pocket Depth)

This is the step people get wrong most often — and it’s the one that matters most for a proper fit.

• Stand the tape measure vertically against the side of the mattress.
• Measure straight up from the floor of the mattress (where it meets the bed frame or platform) to the very top of the surface.
• If you use a mattress topper, add its height to the total. A 12-inch mattress with a 2-inch topper needs an effective 14-inch pocket depth.

For a secure fit, most manufacturers recommend adding half an inch to an inch to your measured thickness. This “give” accounts for the way memory foam compresses under the fitted sheet’s elastic and prevents the corners from popping off during the night.

Step 3: Note Any Irregularities

Antique beds, adjustable bases, RV mattresses, and custom-built frames often have dimensions that don’t match anything on a standard size chart. If your mattress is an unusual shape — rounded corners, a split design, or non-rectangular dimensions — note this separately. A good custom bedding manufacturer can accommodate these details, but only if you flag them upfront.

Step 4: Double-Check Before You Order

Before submitting your measurements:

• Re-measure length and width once more from a different point on the mattress.
• Confirm whether your thickness measurement includes a topper.
• Round up rather than down if you’re between two numbers.

Quick Reference: Measurements to Send Your Bedding Manufacturer

The Payoff of Getting It Right

Once you have accurate numbers, a custom fitted sheet is designed specifically around your mattress — not an approximation of it. The elastic hem sits snugly at the exact depth of your mattress, the corners stay put through the night, and you avoid the slipping and bunching that plague generic “one-size-fits-most” sheets.

If you’re unsure about any of your measurements, it’s always worth reaching out to your bedding provider directly — a quick photo or a follow-up question is far cheaper than reordering a sheet that doesn’t fit.

Looking for bed sheets built around your exact mattress dimensions? At AVIS Bedlinen, we manufacture custom fitted sheets, duvet covers, and pillow covers to your precise measurements — including deep-pocket options for thick mattresses and toppers.