Cosco World’s Greatest Multi-Position Ladder Review

A heavyweight champion of articulated ladders

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Cosco World’s Greatest Multi-Position Ladder

Cosco World’s Greatest Multi-Position Ladder

The Spruce / Sarah Vanbuskirk 

What We Like
  • Functions as five ladders in one

  • Very easy transformations

  • Sturdy and secure

  • Well-constructed

What We Don't Like
  • A bit heavy

Cosco World’s Greatest Multi-Position 21-Foot Ladder, also known as the All-in-One Ladder, elegantly contorts into five unique ladder configurations and swiftly satisfies any reaching needs—from 1 foot, 7 inches to 11 feet, 7 inches in the A-frame position and up to 19 feet in extension mode.


Cosco World’s Greatest Multi-Position Ladder

Cosco World’s Greatest Multi-Position Ladder

The Spruce / Sarah Vanbuskirk 

We purchased the Cosco World’s Greatest Multi-Position Ladder so our expert reviewer could put it to the test at her home. Keep reading for our full product review.

Whether you need to change the lightbulbs, paint the walls, or clean the gutters, a ladder makes it possible to tackle tasks with ease. And an articulated model, like Cosco World’s Greatest Multi-Position Ladder (also called the All-in-One Ladder), available in 13-foot, 17-foot, and 21-foot models, can be set up in several different ways, increasing its functionality as a household tool. Here, I try out the 21-foot version of the so-called “World’s Greatest” ladder to see if it lives up to its name and warrants a spot in your garage. 

Design: “World’s Greatest,” indeed

This three-piece ladder consists of two outer units that telescope over one inner ladder unit. It’s designed to offer five ladder configurations: a traditional extension ladder, an A-frame or step ladder, a stairway ladder, wall ladder, and scaffold—just about everything you could want. Additionally, it adjusts to 10 heights in extension ladder mode (11 to 19 feet), nine in stairway ladder position (5 to 9 feet), five in step ladder (5 to 9 feet), four in wall ladder (5 to 9 feet), and three in scaffold (1 to 3 feet). 

Cosco World’s Greatest Multi-Position Ladder
 The Spruce / Sarah Vanbuskirk

There are two locking systems, including center hinges that allow for the different configurations, and rail lock pins, which enable the different heights. The adjustments are the easiest, most intuitive I’ve experienced. (Though if you do need help, a detailed manual features easy-to-follow instructions and diagrams that demonstrate exactly how to configure the ladder into any one of its possible shapes.)

I used the ladder to touch up paint in my kitchen and in the stairway, utilizing the scaffolding, stairway, and A-frame shapes. Transforming the ladder from one mode and size to another was a breeze. 

Cosco World’s Greatest Multi-Position Ladder
 The Spruce / Sarah Vanbuskirk

I love that the locked and unlocked positions on the hinges have an easy visual indicator to let you know when it’s locked (the two arrows on the hinge lock knobs are aligned) or not (the arrows are not aligned). To release the locks, you simply press on the hinge lock knobs and rotate in the direction of the arrow until you hear the click of the lock releasing. From this open position, the ladder can be adjusted into a new position.

Safety: Type IA handles heavy loads

This ladder is constructed of high-quality aluminum, with solid rungs, slightly flared legs, and slip-resistant feet. The 21-foot model (and one of the 17-foot and 13-foot options) meets ANSI (American National Standards Institute)’s safety standards for Type IA workload. Ladders categorized as Type IA are heavy-duty and can hold up to 300 pounds, so they're suitable for industrial tasks involving carrying materials. Cosco also offers Type II 13-foot and 17-foot ladders with a weight capacity of 225 pounds, so be sure you buy the right option for your purposes.

Cosco World’s Greatest Multi-Position Ladder
 The Spruce / Sarah Vanbuskirk

I felt very secure and comfortable when working on the ladder (though you should always make sure the surface you're working on is flat and stable and can support the weight of both the ladder and you, and read the manual for more safety tips). When in step ladder position, the steps can be climbed on both sides, but in stairway mode, only the short end should go on the step. In any position, there was barely a wobble, which is a vital feature for a heights-averse ladder-climber like me. 

Maintenance: Nothing to it

Ladders are pretty much maintenance-free, and this one is no different. The rust-free aluminum can stand getting wet, but as I live in the perpetually rainy Pacific Northwest, I try to keep mine covered when not in use. To clean, simply wipe down with a damp cloth. 

This ladder folds down to a compact size (5 feet, 7 inches), making it easy to store. However, it is on the heavy side, at just under 42 pounds, so it can be a bit unwieldy to cart around.

Price: On the money

Cosco World’s Greatest Multi-Position 21-Foot Ladder has an MSRP of $214.99. This is a good price for a very well-made, versatile product and about average for ladders of its type.

Cosco World’s Greatest Multi-Position 21-Foot Ladder vs. Little Giant 22-Foot Velocity Multi-Use Ladder

I tested both of these articulation ladders and found they share most of the same features and specifications and are both excellent buys. The main pros for the Little Giant is that it can extend a foot taller in height and is a bit lighter, weighing in at just under 40 pounds, compared with the Cosco model’s 42 pounds. However, while they both offer quick, secure adjustments, I found that the Cosco Ladder was easier to use, which I’d say gives it the win. However, if you need a slightly lighter weight or taller ladder, choose the Little Giant.

Final Verdict

Buy it!

Cosco World’s Greatest Multi-Position 21-Foot Ladder is no joke. Masterfully crafted and easy to operate and adjust from position to position, this ladder tackles all your ladder needs like a true champ.


  • Product Name World’s Greatest Multi-Position 21-Foot Ladder
  • Product Brand Cosco
  • MPN 20421T1ASE
  • Price $214.99
  • Weight 41.8 lbs.
  • Product Dimensions 227.56 x 27.17 x 4.92 in.
  • Warranty 10 years, limited