How To Measure For Deep Seating Outdoor Cushions
How to Measure Deep Seating Patio Furniture Cushions (Sofa, Loveseat, Lounge Chair)
Deep seating patio furniture is made for real lounging—thicker cushions, a more relaxed seat, and a “sink in and stay awhile” feel. It’s also one of the most common categories customers replace, because upgrading cushions is far less expensive than replacing upscale outdoor furniture.
This guide shows you exactly how to measure deep seating replacement cushions for outdoor lounge chairs, sofas, and loveseats. If you measure once and measure correctly, you’ll get cushions that look tailored, fit properly, and bring your furniture back to life.
What Is Deep Seating Patio Furniture?
Deep seating refers to lounge-style outdoor seating that uses separate seat and back cushions (often thicker than dining cushions). You’ll see deep seating in:
Outdoor lounge chairs
Outdoor loveseats
Outdoor sofas
Sectionals (measured similarly, but we’ll cover those in a separate topic)
Deep seating is not the same as dining chair cushions, chaise lounge cushions, Adirondack cushions, or wicker contoured seat cushions—those are measured differently.
Before You Measure: What You’ll Need
Grab a few basics so you can measure accurately:
A tape measure (a rigid tape measure is best)
Paper + pen (or notes on your phone)
Your phone camera (photos help confirm shapes and style)
Optional: a straight edge or ruler to help “square” corners when measuring
Pro tip: Measure in inches, and write down each number as you go. A quick sketch labeled W × D × T makes everything easy later.
Step-by-Step: How to Measure a Deep Seating Seat Cushion
Most deep seating seat cushions are measured as:
Width (W) × Depth (D) × Thickness (T)
1) Measure Width (W)
Measure left to right across the front of the seat area.
If you’re measuring the furniture (recommended), measure the inside width of the seating space where the cushion sits.
2) Measure Depth (D)
Measure front to back across the seating area.
For deep seating, this is typically deeper than dining furniture—don’t guess.
3) Measure Thickness (T)
Measure the cushion height at the thickest point.
Don’t compress the cushion while measuring—measure it as it sits naturally.
4) Note Shape Details (Very Important)
Not all deep seating seat cushions are perfect rectangles. Make a note if you have:
Rounded front corners
A curved front edge
Tapered sides
A curved back edge
Cascadia measuring rule: If your old cushion is misshapen, flattened, or “smaller” than it used to be, don’t copy it blindly. Old foam compresses over time. When in doubt, measure the seating well (the space the cushion fills).
Step-by-Step: How to Measure a Deep Seating Back Cushion
Deep seating back cushions are usually measured as:
Width (W) × Height (H) × Thickness (T)
1) Measure Width (W)
Measure left to right across the widest part of the back cushion.
2) Measure Height (H)
Measure from bottom to top of the back cushion.
3) Measure Thickness (T)
Measure the cushion thickness at the thickest point.
4) Note Back Cushion Style
Back cushions vary a lot. Take a quick note if yours is:
Boxed (square sides, structured look)
Knife edge (tapered edge, more relaxed profile)
Curved at the top
Tapered on the sides
Contoured to fit a frame
Back cushions are one of the biggest sources of measuring mistakes—especially on sofas and loveseats—so photos are very helpful.
Measuring for Sofas and Loveseats
Deep seating sofas and loveseats typically use either:
Option A: Separate Seat Cushions (Most Common)
You may have 2 or 3 separate seat cushions and matching back cushions.
Measure each seat position if possible—some frames vary slightly from left to right.
Option B: One Bench Seat Cushion
A single long cushion (bench style) can look clean and upscale, but it must be measured carefully:
Measure the full inside width of the seating space
Confirm whether arms, posts, or frame angles reduce usable space
Note whether the seat edge is straight or slightly curved
For backs, sofas and loveseats may have:
Two separate back cushions
Three separate back cushions
One long back cushion (less common)
Best practice: For sofas and loveseats, we recommend taking a clear photo of the furniture without cushions and a photo with cushions in place. That helps confirm layout and style.
Common Measuring Mistakes to Avoid
Avoid these (they’re the biggest reasons cushions don’t fit the way customers expect):
Measuring the outside of the frame instead of the inside seating space
Copying measurements from a flattened, shrunken, or distorted old cushion
Forgetting that some seats taper (wider in front than the back, or vice versa)
Not noting rounded corners, curves, or angled sides
Guessing thickness instead of measuring it
Ignoring cushion count and layout on sofas/loveseats
Cascadia fit standard: A properly fitted deep seating cushion should sit securely and look intentional—no sliding, no bunching, no big gaps.
Fit Guidance: Snug Fit vs Relaxed Fit
Deep seating cushions can be made to fit in different ways depending on your style and your furniture.
Snug Fit (Tailored Look)
Clean, upscale appearance
Cushions stay in place
Great for higher-end patio furniture
Relaxed Fit (More Casual Look)
Slightly easier to remove
A softer, less structured look
Works well for casual seating styles
If you’re between sizes, choose the fit style you prefer—and if you’re not sure, Cascadia can help you decide based on your furniture style and photos.
Measurement Cheat Sheet
Use this quick format when writing down measurements:
Seat Cushion: Width × Depth × Thickness
Back Cushion: Width × Height × Thickness
Sofa/Loveseat: confirm number of cushions, and whether the seat is bench or separate
Photo Checklist: What to Send for the Best Results
If you’d like us to help confirm sizing or shape details, send:
A straight-on photo of the full piece
A photo of the furniture without cushions (shows the seating well)
A photo of the furniture with cushions
Close-ups of corners, curves, or unusual shapes
Any label info (brand/model) if you have it
Photos make it easier to confirm what type of deep seating cushion you need and avoid common mistakes.
Deep Seating Cushion Measuring FAQ
What counts as deep seating patio furniture?
Deep seating is lounge-style outdoor furniture—lounge chairs, loveseats, sofas, and many sectionals—designed with thicker seat and back cushions for relaxed comfort.
Do I measure the cushion or the furniture frame?
For the most accurate fit, measure the seating space (the cushion well). Old cushions can flatten or deform and may not reflect the correct size anymore.
How accurate do my measurements need to be?
Accurate measurements matter. Deep seating cushions should fit cleanly and sit properly. Measure carefully, don’t compress the cushion, and write everything down as you go.
What if my seat is curved or tapered?
Note it. Many higher-end frames are not perfect rectangles. A quick photo and a note about the curve or taper helps confirm what you need.
Can I replace deep seating cushions instead of buying new furniture?
Absolutely—and it’s one of the best upgrades you can make. New custom cushions refresh the look and comfort of better-quality patio furniture for much less than replacing the entire set.
My cushions slide around—will new cushions help?
Yes. Proper sizing and construction make a big difference in how cushions sit and stay in place.
Need Help Measuring? Contact Cascadia
If you’re not sure about measurements, cushion count, or shape details—reach out. Deep seating furniture comes in a wide range of styles, and a quick measurement check can save time and frustration.
At Cascadia Outdoor Cushions, every cushion is custom-made to order for better-quality patio furniture—so your deep seating set gets the fit, comfort, and polished look it deserves.
Mini Measurement Diagram Caption (to pair with an image)
Deep Seating Cushion Measuring Guide: Measure seat cushions as Width × Depth × Thickness (W × D × T) and back cushions as Width × Height × Thickness (W × H × T). For the best fit, measure the inside seating space (the cushion well) and note any curves, tapers, or rounded corners.