Quick answer

Choose the Walkin' Wheels SMALL Dog Wheelchair if your dog weighs 11–25 lbs, and the MEDIUM Dog Wheelchair if your dog weighs 26–49 lbs. The size you pick determines which front wheel attachment fits later: the SMALL Front Wheel Attachment for the small chair, and the MEDIUM Front Wheel Attachment for the medium chair. Weigh your dog first—the number, not the breed, decides the size.

The weight ranges do the deciding

Walkin' Wheels sizes are built around weight, not breed names. The SMALL rear wheelchair is created for small pets weighing between 11 and 25 pounds. The MEDIUM rear wheelchair supports pets weighing between 26 and 49 pounds. That single number is the first filter, and it is also the one owners most often get wrong by guessing from breed reputation or a previous dog's size. If your dog sits right at 25–26 lbs, weigh again on a accurate scale and consider how much condition the dog may gain or lose during recovery, because the chair needs to fit the dog you have now, not the dog you expect in three months.

Front attachments do not cross sizes

If your dog later needs front support as well as rear support, the front wheel attachment must match the rear chair's size. The SMALL Front Wheel Attachment is designed for pets weighing 11–25 lbs and transforms your SMALL Walkin' Wheels Rear Wheelchair into a Full Support (Quad) Wheelchair. The MEDIUM Front Wheel Attachment is designed for pets weighing 26–69 lbs and transforms your MEDIUM or MEDIUM/LARGE Rear Walkin' Wheels Wheelchair into a Full Support (Quad) Wheelchair. Note the medium attachment's upper range reaches 69 lbs, so a dog between 50 and 69 lbs may use the medium front attachment paired with a medium or medium/large rear chair. Buying the wrong rear size locks you out of the matching front attachment later, which is why the initial size decision matters more than it first appears.

What each chair is actually for

The SMALL rear wheelchair provides hind leg support so your best friend can continue to run, play, and enjoy an active life, helping with rear leg weakness, paralysis from IVDD or DM, and difficulty walking. The MEDIUM rear wheelchair provides rear support for paralyzed and injured pets, whether the cause is joint pain, dysplasia, IVDD, Degenerative Myelopathy, or recovery from a cruciate injury. Both are rear-support chairs first. The difference is the dog they are built around: a lighter, smaller frame for the 11–25 lb range, and a larger frame for the 26–49 lb range. Neither size is inherently more capable—they are the same design scaled to different bodies.

How to confirm your size before ordering

Weigh your dog on a scale you trust, ideally more than once on different days. Write the number down. If it lands between 25 and 26 lbs, treat that as a boundary case and recheck before ordering, because the two chairs do not overlap in their stated ranges. Then think ahead: if front limb weakness is already present or your vet expects it, plan for the matching front wheel attachment at the same time so you are not caught without the right size later. Finally, check the return and exchange terms before purchase, since a wrong-size chair is the most common reason owners need to swap. Walkin' Wheels publishes a separate measuring guide for the fit details beyond weight, and that guide is worth reading before you finalize.

Trade-offs at a glance

  • Small chair: lighter and easier to maneuver: The SMALL rear wheelchair is built for 11–25 lb pets, which keeps the frame lighter and easier for a small dog to move. The trade-off is a lower weight ceiling: a dog that gains condition or grows past 25 lbs will need a medium chair, and the small front attachment will no longer fit. Best when your dog is comfortably inside 11–25 lbs and unlikely to cross 25 lbs.
  • Medium chair: more capacity, larger frame: The MEDIUM rear wheelchair supports 26–49 lb pets and pairs with the MEDIUM Front Wheel Attachment, which itself covers 26–69 lbs. The trade-off is a bigger, heavier chair that can feel like more equipment for a small dog, and it costs more than the small size. Best when your dog is over 25 lbs, or when you need the wider front-attachment range up to 69 lbs.
  • Front attachment must match rear size: The SMALL Front Wheel Attachment fits only the SMALL rear chair, and the MEDIUM Front Wheel Attachment fits the MEDIUM or MEDIUM/LARGE rear chair. You cannot mix a small attachment with a medium chair or vice versa. This makes the initial rear-chair size the decision that controls your future options. If front support is likely, choose the rear size that matches the front attachment range you need.

Product facts

  • Walkin' Wheels SMALL Dog Wheelchair: Created for small pets weighing between 11 and 25 pounds, the Walkin' Wheels Small dog wheelchair provides life-changing support to keep pets active. The small rear dog wheelchair provides hind leg support so your best friend can continue to run, play, and enjoy an active life, helping with rear leg weakness, paralysis from IVDD or DM, and difficulty walking. This is the right rear chair for a dog in the 11–25 lb range, and it is the only rear chair that accepts the SMALL Front Wheel Attachment if front support is needed later.
  • Walkin' Wheels MEDIUM Dog Wheelchair: The Walkin' Wheels Medium dog wheelchair provides rear support for paralyzed and injured pets weighing between 26 to 49 lbs. It gives medium sized dogs the rear leg support they need to stay active and continue to run and play, whether the dog is struggling to walk due to joint pain or dysplasia, is paralyzed from IVDD or Degenerative Myelopathy, is recovering from a cruciate injury, or is experiencing general hind leg weakness. This is the rear chair for dogs over 25 lbs up to 49 lbs, and it pairs with the MEDIUM Front Wheel Attachment for full support.
  • Walkin’ Wheels SMALL Front Wheel Attachment: The Walkin' Wheels SMALL Front Wheel Attachment is designed for pets weighing 11–25 lbs and transforms your SMALL Walkin' Wheels Rear Wheelchair into a Full Support (Quad) Wheelchair. It provides balanced support on all four legs, helping your small dog stay mobile, maintain stability, and enjoy a more active lifestyle. This is the only front attachment that fits the SMALL rear chair, so choosing the small rear size commits you to this attachment if front support becomes necessary.
  • Walkin' Wheels MEDIUM Front Wheel Attachment: The Walkin' Wheels MEDIUM Front Wheel Attachment is designed for pets weighing 26–69 lbs and transforms your MEDIUM or MEDIUM/LARGE Rear Walkin' Wheels Wheelchair into a Full Support (Quad) Wheelchair. It allows your dog's rear wheelchair to adapt as their mobility needs change, providing balanced, all-over support. This attachment covers a wider weight range than the medium rear chair itself, so a dog between 50 and 69 lbs can still be supported in full support configuration using a medium or medium/large rear chair.

Which size should you choose?

Choose the SMALL if

  • Your dog weighs 11–25 lbs and is stable at that weight
  • You want the lighter, smaller rear chair for a small dog with rear leg weakness, IVDD, or DM
  • You may need front support later and your dog is within the small attachment's 11–25 lb range

Choose the MEDIUM if

  • Your dog weighs 26–49 lbs and needs rear support
  • Your dog is between 50 and 69 lbs and you need full support using the medium front attachment with a medium or medium/large rear chair
  • Your dog is near 25 lbs and may gain weight, or your vet expects front limb weakness that would require the medium front attachment range