Trekking Pole Tarp Height Calculator

How tall should a tarp be? It’s a question of inches. But it’s also the difference between waking up wet and warm, versus finding your sleeping bag drenched after the rain came down and the tarp dipped lower then expected.

That result stems from a geometric relationship: the width of your tarp and how far apart the stakes sits on the ground. How wide a tarp is splayed open to the sky. And all the rest flows from there.

How to Set Up Your Tarp Correctly

It seems most people just guess at their setup, then wonder why they have no room left on one side or why wind gets under the end. The problem is that when you stretch out the sides, you are also stretching amount of fabric available for height. Pull the stakes too far apart and ridge drops; pinch them together to increase headroom and now you lack usable floor space.

Use the calculator above to input your tarp width and distance between your stakes. The calculator will do the math so you don’t have to guess if there is enough fabric to get the height you want.

Most backpackers don’t think about fabric types very much. But type of fabric impacts things more than you’d think. If you have silnylon, then your ridge will sag even farther than it was at sundown because this fabric tend to stretch when wet. With DCF, it doesn’t stretch as much, but the tightness is going to punish any sharp pole tip. This way, with the sag input on the tool, you can adjust for that beforehand so you don’t get that nasty shock of a sagging roof that’s suddenly too close to your head. A small bit of extra allowance there go a long way.

There are a few other subtle variables such as pole lean. The ridge ends don’t always get pitched so that you’re good with the poles standing perfectly vertically. There’s a slight angle which require a bit longer of a pole to reach exact same vertical height. This accounts for the lean setting and what it tells you is whether you should pitch down or not since you might still be able to use your longest trekking pole. Lots of folks find out they’ve been pushing their poles to the very maximum all along, and just didn’t know it.

The other factor is how ground slopes along the ridge. Sometimes there’s only a couple inches difference between front and back, but that can require different poles on either end. You won’t fight an uneven pitch all night; the tool will split that difference for you and let you know what pole goes where. It will also indicate how far out the front guyline stake should go, important if you’re working around rocks and roots and are squeezed onto a small platform.

The numbers are translated to real situations in tables accompanying the calculator and it’s worth a quick look. They show how much sag reserve different fabrics requires. They also show why a ventilation pitch creates raised sides, while a storm pitch does the opposite by keeping edges low. It gives you the reference points without making you have to remember formulas.

The numbers eventually provide you with a means of making deliberate tradeoffs: Do I want greater wind protection at the expense of less head room? Can I place my stakes widely or must they be closer together due to site constraints? Will my poles reach as far into space once leaning and sagging is accounted for?

When you know those relationships, setting up ceases to be guesswork and becomes an option that you can repeat when you next set out with another tarp. You should of used this tool before. It makes livig much easier. If you want a luxurius setup, it helps.