Ever looked at a throw pillow and wondered if you are measuring it correctly? Whether you are replacing a worn insert, shopping for a new cover, or styling your sofa, knowing how to measure throw pillows is a fundamental skill. Getting the dimensions right ensures a plump, wrinkle-free look instead of a sloppy, deflated mess. This guide will walk you through the entire process, from tools to technique, so you can achieve that designer finish every time.
Why Measuring Throw Pillows Correctly Matters
Many people assume all square pillows are the same size, but even a half-inch difference can ruin the aesthetic. A cover that is too small will burst at the seams, while one that is too large looks baggy and unkempt.
Accurate measurements are crucial when ordering new throw pillow covers online. They also help you pair the right insert with the cover, a trick interior designers use to make pillows look extra full.
Beyond looks, proper sizing extends the life of your pillows by reducing stress on zippers and seams. Once you understand the basics, you will never buy the wrong size again.
What You Need Before You Start
Gathering the right tools makes measuring simple and precise. You do not need fancy equipment, just a few household items.
- A flexible fabric measuring tape, because a rigid ruler will not conform to the pillow’s shape
- A notepad and pen to record measurements immediately
- Your pillow, placed on a flat, clean surface
- Optional: a straight edge or yardstick for oversized floor pillows
Always measure the pillow itself, not the cover, unless the cover is permanently attached. If the pillow is very soft or floppy, lightly fluff it first to return it to its natural shape.
How to Measure a Throw Pillow: The Standard Method
When someone asks how to measure throw pillows, they usually mean square or rectangular cushions. Follow these steps for accurate results every time.
Step 1: Lay the Pillow Flat
Remove any decorative cover and place the pillow insert on a hard surface like a table or floor. Smooth out wrinkles and reshape the pillow so it forms a neat square or rectangle. Do not press down too hard, just let it naturally expand.
Step 2: Measure from Seam to Seam
Using your flexible tape, measure the width from one side seam to the opposite side seam, not including any ruffles, piping, or trim. For a square pillow, you only need one width measurement because all sides are equal. For a rectangular lumbar pillow, measure both the width and the length.
Keep the tape measure taut but not stretched. The goal is to capture the exact dimensions of the pillow’s body. Write down the number immediately.
Step 3: Confirm the Depth (Optional)
Pillow depth, or loft, is less critical for covers but matters when choosing inserts. To measure depth, stand the pillow on its side and measure from the tabletop to the highest point. A standard throw pillow might be 5 to 6 inches thick, while a luxury insert can be 7 or more.
Write down all measurements in the format width x length (or width x length x depth). For a classic 18×18 inch pillow, you will note 18×18.
Measuring for Pillow Covers vs. Inserts
Many beginners confuse measuring for a cover with measuring for an insert. These two tasks are related but not identical, and mixing them up leads to a poor fit.
Measuring an Existing Insert to Buy a New Cover
If you have a naked insert, simply measure its seam-to-seam width and length. Purchase a cover that matches those exact dimensions. A well-made cover will have a finished size that accommodates the insert, but to get that ultra-plump look, many decorators buy an insert one size larger than the cover. For instance, a 20×20 insert in an 18×18 cover looks full and luxurious.
This upsizing trick is one reason you need precise measurements. You can experiment with different insert sizes to change the pillow’s personality.
Measuring a Cover to Select the Right Insert
When you have a cover but no insert, lay the empty cover flat and measure its inside dimensions from seam to seam. This tells you the finished size. Then choose an insert that is either the exact size for a relaxed look or up to two inches larger for a firmer, fuller appearance. Just avoid an insert more than three inches larger, or it will be impossible to zip closed.
If you need help picking the right cover material, take a look at our roundup of the best throw pillow covers available this year. High-quality covers can make even a budget insert look expensive.
Measuring the Entire Pillow When You Cannot Remove the Cover
For pillows with non-removable covers, measure the whole piece from seam to seam. Treat that number as the cover size. Since the pillow is already filled, this method works for ordering a replacement of the same style.
Standard Throw Pillow Sizes Explained
Throw pillows come in a few predictable dimensions, which makes shopping easier once you know the lingo. Here are the most common standard sizes you will encounter.
- 16 x 16 inches: A compact square used on accent chairs or in layered arrangements.
- 18 x 18 inches: The classic throw pillow, ideal for sofas and loveseats.
- 20 x 20 inches: A larger square that provides generous support and makes a statement.
- 22 x 22 inches: An oversized square, great for deep sectionals and modern minimal looks.
- 12 x 20 inches or 14 x 22 inches: Lumbar pillows, perfect for lower back support and layering in front of squares.
- 12 x 24 inches or 14 x 36 inches: Elongated lumbar pillows used on benches or king beds.
If your measurements fall between these numbers, you probably have a custom or imported pillow. In that case, use the exact measurements you recorded and look for a custom cover maker. For additional sizing guidance across different furniture, check out our detailed guide to decorative pillow sizes for a king bed.
How to Measure Specialty and Odd-Shaped Throw Pillows
Not every throw pillow is a neat square. Bolsters, rounds, and bolster-wedges require slightly different techniques.
Round or Circle Pillows
For a round disc pillow, measure the diameter across the widest point, seam to seam. Do not include any decorative edge. The depth can be measured as for a square pillow, from the tabletop to the center peak.
Bolster and Cylinder Pillows
Measure the length from end to end along the seam, and the circumference around the fattest part of the cylinder. Some covers are sized by diameter instead of circumference, so you may need to divide the circumference by 3.14 to get the diameter. Provide both numbers to the seller if you are unsure.
Wedge and Neck Pillows
Wedge pillows are measured by the width, depth, and the height of the highest point. Since these pillows have a slope, note the dimensions of the base and the peak. Measuring carefully here prevents ordering a cover that is too tight at the thick end.
Regardless of shape, always measure at the widest and longest points. Taking the time to get these numbers right saves you from costly returns.
Common Measurement Mistakes and How to Avoid Them
Even experienced decorators slip up now and then. Here are frequent pitfalls and how to sidestep them.
- Measuring the cover instead of the insert. A stretched cover can appear larger. Always remove it if possible and measure the insert inside.
- Including piping or trim in the measurement. Piping is decorative, not structural. Measure only the flat fabric panel from seam to seam.
- Measuring a squashed, old pillow. Fluff the pillow fully to its original loft before measuring. A deflated insert will give you smaller dimensions.
- Rounding down too aggressively. If your pillow measures 18.5 inches, do not order an 18-inch cover hoping it will stretch. Precision matters. Go with the exact size or upsize the insert.
- Ignoring the depth for a zip cover. Some specialty covers have a gusset that requires a specific thickness. Check product descriptions for depth recommendations.
Taking a few extra seconds to double-check your numbers can prevent the frustration of a poorly fitting pillow.
Styling Tips Based on Pillow Measurements
Once you know your pillow dimensions, you can use that knowledge to create balanced, inviting spaces. Interior designers follow simple rules that anyone can adopt.
The Rule of Odd Numbers
Arrange pillows in groups of three, five, or seven for visual harmony. On a typical three-seat sofa, try a 22×22 inch oversized square in the corner, a 20×20 inch middle pillow, and a 12×20 inch lumbar in front.
Scale to Your Furniture
A massive sectional can handle 24-inch square pillows, while a petite armchair looks better with 16-inch or 18-inch squares. Always measure your seating area before buying. A good rule of thumb: the pillow should cover no more than one third of the seat depth.
Mix Sizes for Depth
Using a combination of sizes adds layers. Start with larger pillows at the back, then layer smaller ones in front. The variation in dimensions draws the eye and makes the arrangement look intentional.
If you need more inspiration home decor, Havenly offer excellent advice on pairing inserts and covers to achieve a designer finish.
Frequently Asked Questions
Do I measure the pillow with or without the cover?
Remove the cover and measure the insert for the most accurate dimensions. If the cover is not removable, measure the pillow as is and treat that number as the cover size.
What if my pillow has rounded corners?
Measure from seam to seam at the widest part of the pillow. Rounded corners do not change the functional dimensions, and standard covers are designed to accommodate slight curves.
Is it better to buy an insert larger than the cover?
Yes, a common decorator trick is to use an insert two inches larger than the cover for a plump, high-end look. For example, a 20×20 insert fills an 18×18 cover beautifully. Just do not exceed a three-inch difference, or the cover may not close.
Can I use a ruler instead of a tape measure?
A flexible tailor’s tape is best because it follows the pillow’s contours. A ruler works in a pinch for small squares but is less accurate for larger or softer pillows.
Why does my brand new 18×18 pillow look flat?
If the insert is exactly 18×18 and the cover is also 18×18, the corners may not fill completely. Try fluffing the insert or replacing it with a 20×20 size. Also, consider upgrading your cover material to a thicker fabric that holds its shape better.
Conclusion
Measuring throw pillows is a simple skill that pays off every time you refresh your decor. By following the seam-to-seam method, understanding the difference between cover and insert sizing, and avoiding common traps, you can order with confidence. The key is to measure twice, write down your numbers, and never assume a one-size-fits-all approach.
Take a few minutes now to measure the pillows you already own. You might discover they are not the size you always assumed. With the right measurements, your next pillow purchase will look professionally styled and feel intentionally comfortable.