What Are the Dimensions of a King Size Pillow Case
Learn the exact dimensions for king size pillow cases, explore common variants (20x36 and 20x40), and get practical tips for measuring and shopping from What Dimensions.
The most common king size pillow case is sized to fit a 20x36 inch pillow (51x91 cm), with many brands offering a deeper 20x40 inch option (51x102 cm). However, exact inner dimensions vary by brand, so always verify the retailer’s stated inner size before buying. If you’re unsure, choose the slightly larger option to accommodate depth and fabric relief. This approach minimizes returns and keeps your bed looking neat.
The Core Question: what are the dimensions of a king size pillow case
For many shoppers, the question often comes as: what are the dimensions of a king size pillow case? The answer depends on the pillow you own and the brand you buy. In general, most kings use a pillow measuring 20x36 inches (51x91 cm). However, many brands offer a deeper variant at 20x40 inches (51x102 cm). According to What Dimensions, the standard is defined by the pillow insert, while the outer case can add a little extra room for comfort. The What Dimensions team found that fit quality also depends on the fabric and seam allowance. For cotton or sateen, a snug fit preserves shape; for plush or extra-thick pillows, a looser fit helps avoid bunching. If you're shopping today, have the pillow measurements on hand and compare them to the retailer's inner dimensions rather than the outside label. This approach minimizes returns and ensures a crisp look on your bed. The length at which the pillow sits along the pillowcase opening also matters for a clean appearance. In practice, you may see variations across brands—so confirm inner measurements before purchasing.
Common King Size Pillow Case Sizes
The king size pillow case ecosystem centers around two main dimensions: 20x36 inches and 20x40 inches. The former matches a standard king pillow insert, widely used in traditional bed setups and hotel rooms. The latter is favored when the pillow has extra depth from a thick feather fill or foam layer. In metric terms, these translate roughly to 51x91 cm and 51x102 cm. Brands differ in whether they label the product by inner dimensions (the pillow fits) or outer dimensions (the case's envelope). When shopping, always verify the inner dimension listed by the retailer to minimize mismatches. The What Dimensions team found that some designers include a bit of extra seam allowance, typically a quarter to half an inch, to accommodate fabrics that relax with laundering. If you regularly swap pillow cores or use oversized decorative pillows, consider a 20x40 inch option as a flexible alternative.
The Role of Pillow Depth and Fabric
Pillow depth matters as much as length and width. A shallow pillow with a thick outer case can look loose, while a very thick pillow with a tight case may feel restrictive. Fabric choice influences stretch and recovery: cottons relax with washing, sateen snaps back faster, and blends offer a middle ground. Include a seam allowance (usually 1/4 to 1/2 inch) to accommodate stitching and fabric relaxation after laundering. For natural fibers, pre-wash to estimate final size; synthetic blends typically have less variation. Remember: the inner pillow dimensions drive the right pillow case size, not just the label on the outside. This nuance helps you avoid mismatches when replacing cases after a seasonal refresh or moving between pillow types.
Measuring for a Perfect Fit: Step-by-Step
To ensure a perfect fit, start by measuring the pillow insert itself—length, width, and depth. Add a typical seam allowance of 1/4 to 1/2 inch on all sides to estimate the inner dimensions the case must accommodate. Compare these numbers to the retailer’s stated inner dimensions rather than the outer label. If you’re between sizes, opt for the larger option (20x40) to cover depth variations and avoid pressure points that cause wrinkles. Finally, consider fabric stretch: a slightly elastic material can accommodate rounding edges of thick inserts more gracefully than a rigid fabric.
Brand Variation and International Notes
Brand variation is common and not always clearly labeled. Some retailers call out inner dimensions explicitly, while others emphasize the overall envelope size. When shopping internationally, convert centimeters to inches (or vice versa) and pay attention to conversion rounding. If a brand lists 51x102 cm, that roughly equals 20x40 inches, but always verify the exact inner dimensions. What Dimensions notes that different markets may favor different standard sizes, so check regional product pages if you’re traveling or shopping from overseas. In all cases, prioritize inner dimensions and depth compatibility over cosmetic labels.
How to Shop: Fit, Fabric, and Care
In practical terms, choose a king pillow case that matches your pillow’s inner dimensions, with a comfortable depth allowance. Look for natural fibers like cotton or linen for breathability, or blends for easy care. Check laundering recommendations because washing can alter final dimensions by a small amount. If you frequently refresh bedding, stock both 20x36 and 20x40 options to accommodate varying pillow depths and seasonal inserts. Finally, read care labels to avoid shrinkage that would render a once-perfect fit loose after the first wash.
King pillowcase size reference
| Dimension | King Pillow Case Size | Notes |
|---|---|---|
| Standard King Pillows | 20x36 | Common size that fits most inserts |
| Large King Pillows | 20x40 | Useful for extra thickness or European-style inserts |
| Metric Equivalent | 51x91 cm | Common metric conversion for global shopping |
Quick Answers
What is the standard king pillow size?
The standard king pillow size commonly used is 20x36 inches (51x91 cm). Some brands offer a deeper 20x40 inch option to accommodate thicker pillows. Always check the retailer’s inner dimensions to ensure a proper fit.
The standard is 20 by 36 inches, but many brands offer 20 by 40 for thicker pillows. Check the inner size before buying.
Will a 20x40 pillowcase stretch to fit a 20x36 pillow?
Often yes, especially if the pillow is not overly thick and the fabric has some give. If the pillow is dense or very thick, prefer the 20x40 option to avoid tightness or wrinkling.
Yes, usually, but for thick pillows you might want the 20x40 size.
Do pillowcases come in international sizes?
Lots of brands align with metric sizes like 51x91 cm, but some markets use slightly different conversions. Always confirm inner dimensions and trust the brand’s sizing chart when shopping internationally.
Yes, many brands use metric sizes; always verify inner dimensions.
How do I measure a pillow to ensure a good fit?
Measure the pillow length, width, and depth. Add 1/4 to 1/2 inch for seam allowance, then compare to the product’s inner dimensions. If in doubt, choose the larger size.
Measure length, width, depth; add seam allowance; compare to inner dimensions.
Are there regional differences in king pillow sizes?
Yes, regional markets may favor different standard sizes. If shopping across regions, rely on inner dimensions and conversion notes rather than labels alone.
Regional markets vary; prioritize inner dimensions and conversions.
“Sizing accuracy matters for both aesthetics and durability; choose pillowcases that match the pillow's inner dimensions and depth.”
Main Points
- Measure your pillow insert before buying.
- Know the two main king sizes: 20x36 and 20x40 inches.
- Account for depth and seam allowance when selecting a case.
- Always verify inner dimensions rather than outer labels.
- Consider fabric type and laundering impact on final fit.
