40MPH Speed Square Blanket


• 100% polyester sublimated MPH calculator on front
• Instruction label on bottom right corner
• Blue 80% cotton, 20% polyester fleece on back
• Eyelets for hanging on each corner
• Machine washable and dryer safe
• 100% Made in USA
• Dimensions: 96" x 48"

Instructions for Speed Calculator Use:

• Set your phone or camera to film in ‘Slow Mo’ at 240 FPS (frames per second) and film an object as it travels across the grid on your Speed Square Blanket.

• Each Square is 2.19 inches and is equivalent to 1 MPH (mile per hour)

• Watch your video and count the number of squares the object travels in exactly 1 ‘Slow Mo’ second

• If your phone/camera records at 120 fps, then count the number of squares it travels in 1 ‘Slow Mo’ seconds and divide by 2. NOTE: some phones might record at 120 FPS by default but still have the ability to increase that to 240 if you check the settings.

• YOU DID IT! If your object travels 20 squares in 1 ‘Slow Mo’ Second then your item is traveling at 20 MPH!

• To calculate KPH (kilometers per hour) is easy! Just multiply your MPH by 1.6

This blanket is 40 squares wide, making it a 40 MPH blanket. If you want to measure speeds up to 80 MPH you can use two blankets and lay them end to end.
If you want to measure the speed of light, you’re going to need about 16.7 Million blankets. No big deal :)If you’ve already got plenty of blankets but still want to experiment with the science then try the following.  Measure out 2.19" squares on a piece of paper. You can fit 5 on a regular sheet of printer paper, which means you can measure up to 5 MPH. Just remember, more squares = more MPH

NOTE: This blanket is designed for objects traveling horizontally (where the speed isn’t affected by gravity). If you want to know the final speed of an egg dropped from a building right before impact for example then use this formula: Final speed = 1.25 x number of squares + 1.09

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Christine L.
United States United States

Christmas Gifts

I purchased these way ahead of Christmas for both of my boys because they enjoy your videos and quite frankly so do I. We’ll let you know after Christmas how much the boys love them.

Doug R.
United States United States

Makes a great baby blanket!

Haven't used it for any type of slow-motion or blue-screen special effects work yet, but the blue side is super fuzzy and the checkered side, made of a very smooth material, doesn't absorb liquids very well. As such, it makes an absolutely wonderful blanket for my daughter; it stays dry and doesn't stain easily (drool wipes right up), but flip it over and it's super warm and cuddly to nap on. It's much larger than most baby blankets, and he checkerboard pattern also will make it much easier to keep track of her speed once she learns how to crawl.

Elise S.
United States United States


Admittedly, I haven't used it as a speed measurement yet, my camera isn't here yet. But it's a blanket, and it's keeping me warm right now, just like every other day! It's slicker on the front, but fuzzy on the back, which I love because it seals the heat in making it a warm blanket for it's weight! Honestly, my favorite thing is that it's the perfect size to wrap over and under my legs. It does this without so much overhang of blanket that I can't extricate myself. And it's still able to cover 2 people no problem. Really glad I got this, 10/10 would buy again! Thanks Mark, you're a huge inspiration!

Isolina C.
United States United States

Using this Blanket for programming robots

It was successful.

Ashley S.
United States United States

Love this blanket in Louisiana

Our boys are 6 and 8. We use this blanket all the time (for fun videos and as an actual blanket). Big fans over here. Really love all the tabs for hanging it up. Super helpful!

Mark Rober Official 40MPH Speed Square Blanket Review

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