At 30°
×1.0
Force per side ≈ your loaded weight
Free tool · Hammock physics, honestly
How much force do the trees actually take?
When you lie in a hammock, the straps and the trees carry more than your weight — a shallow, tight hang can load each side with two to three times your body weight. Set your weight and hang angle to see the real force on every strap and tree — and why ~30° is the sweet spot.
Real force, not just body weight
kilogram-force & newtons
Kind to the trees
The 30° ruleA comfortably flat lie — and a far gentler load
Why ~30° is the sweet spot
Hang the straps at about 30° from the horizontal and two good things happen at once: the hammock takes on a soft curve that lets you lie flatter and more diagonally — the comfortable position — and the tension on each side settles at roughly your body weight rather than a multiple of it.
Go shallower (tighter, smaller angle) and the hammock looks flat while the force climbs steeply — the same body weight now pulls far harder on straps and trees. Go much steeper (slacker) and the force drops, but you sink into a deep, cocoon-like curve that most people find less comfortable. Around 30° is the honest balance between comfort and load.
At 20°
×1.5
Half again — noticeably tighter
At 10°
×2.9
Almost 3× — a lot to ask of hardware & bark
At 45°
×0.71
Lowest force — but a fairly slack lie
Hang gently
Look after the trees that carry you
Those forces do not only test your gear — they press against living bark. A few honest habits keep the trees healthy and your hang safe for years.
Use wide tree straps
Straps at least 2.5 cm wide spread the load across the bark instead of cutting into it. The wider the strap, the gentler the pressure — and the safer the hang.
Never bare line or thin rope
Rope, cord, wire or thin webbing cuts into the bark under these forces and can girdle a tree — a ring of damage that can kill it. If it is narrow, it does not belong against the trunk.
Choose living, healthy trees
Pick two stable, living trees at least 15–20 cm thick (about a firm hug or thicker). Skip dead, leaning, split or hollow trunks — and never wrap a strap so tightly that it rings the whole trunk.
Leave no trace
Hang at a sensible height, keep the wrap high on a wide trunk and take everything with you. Good habits keep places open — for the trees and for the next person hanging there.
An honest note on the numbers
Static figures — reality bounces
These are static estimates: the steady pull while you lie still. The moment you climb in, shift, roll or bounce, the peak force spikes well above the number shown — sometimes by a wide margin. Treat the calculator as a floor, not a ceiling.
So size every part of your suspension with generous margin. Straps, carabiners, hooks and knots should be comfortably stronger than the static figure — the rated working load is your friend, not the breaking strength. If in doubt, hang a little slacker towards 30° and check hardware and knots before trusting them with your full weight above the ground.
More free hammock tools
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