Sectional & L-Shaped Sofa Size Guide

Sectionals and L-shaped sofas look effortless when the fit is right. This guide shows exactly how to measure your sofa in cm + inches and choose the correct separate-piece configuration for a smooth, secure finish.

Quick fit rule: Measure the full length including armrests for each section (A-A, B-B, C-C). L-shaped layouts typically need 2 pieces. U-shaped/large sectionals typically need 3 pieces.

Shop sectional covers Sectional & L-Shaped Sofa Covers Sofa & Couch Covers Chaise Lounge Covers

Looking for extra protection (pets, spills, daily life)? Browse Waterproof Sofa Covers, Anti-Scratch Couch Covers, or Pet Furniture Protection.


What to measure (A, B, C lengths)

Sectionals are measured by runs. For each run, measure the length the cover needs to wrap from outside armrest to outside edge (armrests included where present).

Use these measurements
  • A (A-A): length of the left section (including the armrest).
  • B (B-B): length of the center run (including the armrest if present).
  • C (C-C): length of the right section (including the armrest).

Tip: Measure along the seating line (where the back cushions meet the seat cushions), not around the outside curve.


Choosing pieces:
  • L-shaped sofa: measure two runs and order 2 separate pieces.
  • U-shaped / large sectional: measure three runs and order 3 separate pieces.

If a run has no armrest on one end (because it connects to another section), measure to the connection edge where the cover will end.

Measuring diagrams

Sectional and L-shaped sofa measuring guide showing A-A, B-B, and C-C lengths including armrests.

Size chart (length including armrests)

Select a size for each run you’re covering (A, B, and/or C). If you’re between sizes, choose the size that covers your measured length without forcing the fabric.

Cover size Length range (cm) Length range (in) Best for
1-seater 90–140 cm 35–55 in Armchair / compact module / small sectional segment.
2-seater 145–185 cm 57–73 in Loveseat run / medium sectional segment.
3-seater 195–230 cm 73–91 in Standard sofa run / longer sectional segment.
4-seater 235–300 cm 92–118 in Extra-long run / large main segment.
Good to know: A sectional is sized by runs (A, B, C), not by the overall “end-to-end” sofa length. It’s common to mix sizes (example: 3-seater + 2-seater).

How to choose sizes for L-shaped & sectional sofas

L-shaped sofa (2 pieces)

  • Measure the main run (often A-A).
  • Measure the return/chaise run (often B-B).
  • Use the chart to choose a size for each run.

Example: A-A = 205 cm → 3-seater. B-B = 165 cm → 2-seater.

U-shaped / large sectional (3 pieces)

  • Measure left run (A-A).
  • Measure center run (B-B).
  • Measure right run (C-C).
  • Use the chart to choose a size for each run.

Example: A-A = 175 cm → 2-seater, B-B = 220 cm → 3-seater, C-C = 140 cm → 1-seater.


Cleaner corner join: If your sectional has a corner wedge, measure each upholstered run up to the corner seam and size each piece to that run. This helps the covers meet neatly at the corner.

Measuring steps (fast & accurate)

Use a flexible measuring tape. Measure in cm or inches—just stay consistent. For the most accurate length, measure with cushions in place.

  1. Identify your layout: L-shaped (2 runs) or U-shaped/sectional (3 runs).
  2. Measure each run: For A-A, B-B, C-C measure outside armrest to outside edge (armrests included where present).
  3. Label your numbers: Write A, B, and C so you don’t mix sections.
  4. Match each run to a size: Use the size chart above and select the best range fit.
  5. Install piece-by-piece: Start with the longest run, then smooth and tuck for a refined silhouette.
If you’re between sizes:
  • Just over the limit? Choose the next size up.
  • Comfortably within range? Choose that size for a more tailored fit.

Sectional & L-Shaped Sofa Size Guide FAQ

Do I measure the whole sectional in one go?

Measure each run separately (A-A, B-B, C-C). You’ll choose a size for each piece, then install them together.

Are armrests included in the measurement?

Yes. This guide uses length including armrests where present.

Which product category is best for pets or spills?

For everyday protection, browse Waterproof Sofa Covers, Anti-Scratch Couch Covers, or Pet Furniture Protection. For a lighter layer, Pet Hair Resistant Throws can be a great add-on.

Can I order different sizes for each sectional piece?

Absolutely. Different runs often require different sizes (example: 3-seater + 2-seater + 1-seater).

Where can I find the general sofa sizing guide?

For standard sofas (non-sectional), use the Sofa & Couch Slipcover Size Guide. For smaller sofas, see the Loveseat Slipcover Size Guide.


More size guides (quick links)

Measuring something else? Here are the most relevant guides to keep your home looking polished and protected.

Sofa & Couch Slipcover Size Guide For standard sofas, couches, and straight runs. Loveseat Slipcover Size Guide For smaller sofas and loveseat proportions. Futon & Convertible Sofa Size Guide For sleeper-style seating and fold-down frames. Recliner & Armchair Size Guide For recliners, armchairs, and single-seat comfort. Ottoman & Footrest Cover Size Guide For poufs, ottomans, and footrests. Pet Blanket & Protector Size Guide For throws and pet-friendly coverage layers.

Prefer the full directory? Visit: Sectional & L-Shaped Sofa Size Guide (this page) and browse the other guides from there.


Helpful reads (care, styling, and buying tips)

French design meets everyday living—use these blog hubs to keep your seating fresh, practical, and guest-ready.

Living Room & Sofa Care Everyday upkeep, fabric care habits, and living room refresh ideas. Pets & Furniture Protection Pet hair, claws, and practical ways to protect the pieces you love. Product Guides & Buying Tips Choosing the right cover type, fit notes, and setup suggestions. DIY & Cleaning Tips Simple cleaning routines and quick fixes for real-life messes. Home Décor & Interior Style Timeless styling ideas that work with daily life. Small Spaces & Apartment Living Smart layout ideas and protection for compact homes.

More inspiration: French Lifestyle & Inspiration, Home Essentials & Lifestyle, Home Safety & Family Living, Furniture Restoration & Upcycling, Seasonal & Holiday Décor, Outdoor Living & Patio Style, Office & Productivity Spaces, Eco-Friendly Living, Event & Wedding Inspiration.


Ready to shop your layout?

Once you have A-A / B-B / C-C, choose the matching sizes for each piece. If you’d like, share your measurements and layout, and we’ll help confirm the best combination.

Shop Sectional & L-Shaped Sofa Covers Shop Stretch Sofa Covers Shop Throws & Blankets

This guide is designed for separate-piece sectional sizing using lengths that include armrests (A-A, B-B, C-C). For best results, always confirm your measurements against the size chart shown on the exact product page you’re purchasing.