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Twin XL Equation

Twin XL Math with Dick and Jane...

THE TWIN XL EQUATION – Dick and Jane’s Problem

Dick and Jane are heading to their campuses and each has a 39" x 80” twin XL mattress in their college dorm room, 5” longer than a standard twin mattress. Let’s assume both Dick and Jane’s dorm room mattresses are 8” deep and their mattress topper, bed bug protection, and mattress pad add an additional 2 inches. What size duvet cover and comforter will fit best on Dick or Jane’s twin XL mattress? What is the minimum depth fitted sheet Dick or Jane should use to accommodate their mattress, topper...? Show your work…

80” + 8” + 2” = 90” Long Duvet Cover and Comforter

8" Mattress + 2" Topper = 10" Depth Pocket for Fitted Sheet

THE CONCLUSION – Possible Solutions for Dick and Jane

The math tells us that a standard twin 86” long duvet cover and comforter may not be the best fit for Dick or Jane’s twin XL mattress, 90” or longer would be preferable. While it is possible to make a shorter duvet cover or comforter work, neither should expect 100% coverage… especially if they plan to use additional padding such as a foam topper to make their mattresses more comfortable or choose to raise their beds for storage. Since the availability of twin XL is increasing, Dick and Jane may want to consider purchasing a longer duvet cover and comforter for their beds. As for their fitted sheet, Dick and Jane should shop for a fitted sheet that is 39" x 80" with a 10" Pocket Size or Overall Depth of 13" to ensure their fitted sheet will cover their mattress, additional padding, and provide ample room for the underturn.


  1. Forget the label of Twin XL, focus on the actual bedding dimensions when shopping.

  2. If the bedding dimensions are not listed on the product, ASK for them and do the math.

  3. If the retailer fails to provide the ACTUAL bedding dimensions to you or the twin XL math does not add up... SHOP ON.
At DormSmart, we've learned the best overall strategy to employ when shopping for twin XL bedding… is to encourage student shoppers to check directly with their campus housing office to obtain their dorm room mattress size then shop for the appropriate size bedding using ACTUAL dimensions not labels and do the math.

Shop smart and live dorm smart!

Congratulations on completing Twin XL Math with Dick and Jane!

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