How Big Should a Tent Footprint Be?

Look at some of the tents the next time you go camping at a public campground. Do you see tarps and ground cloths sticking out from the bottom of the tent? If you can see the tent footprint it’s way too big.

How Big Should a Tent Footprint Be? Buy a tent footprint that’s 2″-3″ smaller than the floor of your tent. A footprint that’s bigger than your tent will cause flooding problems in the rain. Water will start to pool on top of the tarp and run underneath the tent causing more harm than good.

Most people don’t realize their tent footprint is a problem until it’s too late. It protects their floor from tears and keeps it clean, but they’ve never tried it out in the rain. Even a light rain can quickly get out of hand with the wrong sized ground cloth.

You might be able to get away with an oversized ground cloth for a while, but it will eventually bite you in the butt. Just do yourself a favor and pick out the right size tent footprint from the start. Don’t wait until it’s too late and your sleeping bag is soaked.

Choosing The Right Size Tent Footprint

You need to figure out the size of your tent before you can choose a ground cloth or tarp. Hopefully, you can figure out the product name and year of your tent.

If you don’t have the packaging you might want to think about where you bought the tent. I was lucky enough to have purchased my last tent on Amazon so looking up my order history was easy. Just check out the specs and head down to the section below.

Don’t Worry! If you can’t figure out the name of the tent you can always set it up and measure it the old fashioned way. Just set up your tent in the yard, get out a tape measure, and get to measuring.

Go 2-3 Inches Smaller Than The Tent Floor

You really need to figure out the size of your tent before making a purchase. Don’t waste your time with a tent footprint that’s too big. Buy a footprint that’s 2-3 inches smaller than the outside dimensions of your tent.

Think about the surface area of the top of your tent. A basic 3 person tent will cover about 81 square feet. The entire surface area of your tent will divert water right onto the top of your tent footprint.

So 1 inch of rainfall over the surface of your tent is 51 gallons of water pooling up around the perimeter of your tent. All that water needs to be able to get down into the ground. Check out the US Government Rainfall Calculator to see how much water is diverted around your tent.

Tent SizeFold Tarp Down to Size and Use a Grommet Kit to SecureAlps Mountaineering Tent Footprint Size
2-Person6×8 Tarp7’2″ x4’8″ Footprint
3-Person8×10 Tarp7’2″ x 6’2″ Footprint
4-Person8×10 Tarp8’2″ x 7’2″ Footprint
5-Person9×12 Tarp9’8″ x 7’8″ Footprint
6-Person12×16 Tarp9’8″ x 9’8″ Footprint
The chart above shows some of the most common tent sizes. Make sure you look up the overall dimensions of your tent and pick out a tarp or footprint that fits your needs. You will have to cut down and modify the above tarps for a proper fit.

You might want to check out Alps Mountaineering’s Website for more sizes. They come in like 20 different sizes. So you should be able to find one that works.

Ask The Manufacturer For Product Specific Tent Footprints

Call up the manufacturer and ask if they sell a tent footprint designed for your tent. Going with a tent footprint specifically designed for your tent is by far the best option available. You will probably have to pay a premium, but it’s so worth it.

Most manufacturers use standard sizing so their entire lineup can use the same ground cloth. Although there’s no industry standard tent size the chart below should get you pretty close.

It really doesn’t matter if you choose a real tent footprint or tarp as long as it’s the right size for your tent. Just keep in mind that you will most likely have to cut down a tarp and install grommets (my grommet kit). I’m constantly adding grommets to random things, but it will increase the cost of a tarp.

Check Out The Tarps At Harbor Freight

After going to 10+ stores without finding much of anything I stumbled upon a goldmine at Harbor Freight. It’s ridiculous how many different size and style tarps they have.

The entire back wall of my local store was completely covered. If you can’t find a tarp that will work for you at harbor freight, you won’t find one anywhere. You might want to check out their selection online before driving to the store.

Custom Tarps are Way Too Expensive

Don’t even bother trying to find a heavy-duty custom made tarp. Custom tarps are almost exclusively used by truckers, landscapers, construction workers, etc.

A custom tarp for my 3-Person tent would have cost me between $30-$70 depending on its thickness. That’s more expensive than just purchasing the one designed for my tent.

How Thick Should a Tent Footprint Be?

Good luck trying to figure out the thickness of your tent footprint. I tried calling around to a few of the different manufacturers and I couldn’t get a straight answer.

It seems like most ultralight models are .5mm thick and heavy-duty versions are 1.5mm thick. So your footprint should fall somewhere inside that range. Thankfully, it really doesn’t matter how thick your footprint is.

Any newish tarp or ground cloth should work. It just needs to be waterproof and somewhat durable. Don’t go with a ratty old tarp that you find in the garage. It needs to be able to withstand a little bit of pressure without tearing.

Making Your Own Tent Footprint Out of a Tarp

Making a tent footprint is really easy. Follow these steps and watch the video above for more information.

  1. Figure out the size of your tent. You’ll have to set out your tent and measure the bottom if you can’t figure out the size. Just flip the tent upside and spread it out on the floor. You should be able to get a measurement without putting the tent up.
  2. Choose a tarp that’s 2-3 inches shorter than the length and width of your tent. It’s better to be slightly smaller than too big. If you can’t find a close match you will have to get a big tarp and cut it down.
  3. Take scissors and cut your tarp down to size. Don’t worry about cutting off grommets they can be added back in later. Save a large piece of the footprint for a later step.
  4. Adding grommets is optional, but it will sturdy up the tent and give you a place to attach tent poles. Don’t spend a fortune on a grommet kit. A cheap Coghlan’s Grommet kit is all you really need.
  5. This is an optional step, but I think it’s well worth the hassle. Take the leftover piece of tarp from earlier and cut out four 8-12 inch strips to use as corner grommet straps. Look at the image below as a reference.
  6. Fold the straps in half and attach them to each corner of your tarp. Just use the grommet kit to attach the strap to your tarp. This should give you good enough connection, but you might want to sew in a few stitches as well.
  7. Set your tent up over the tarp and figure out where your poles line up with the straps. Install another grommet wherever the tent poles line up and place your poles inside. This should keep your tarp footprint from sliding underneath the tent floor.

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