At 30°
×1.0
Force per side ≈ your loaded weight
Free tool · Hammock physics, honestly
How much force do the trees really take?
When you lie in a hammock, the straps and trees don't just hold your weight — a shallow, tight hang can load each side at 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 tension, not just body weight
kg-force & newtons
Tree-friendly guidance
The 30° ruleComfortable lie-flat — and far kinder loads
Why ~30° is the sweet spot
Hang your straps at roughly 30° from horizontal and two good things happen at once: the hammock takes on a gentle curve that lets you lie flatter and more diagonally — the comfortable position — and the tension on each side settles at about your body weight, not a multiple of it.
Go shallower (tighter, a smaller angle) and the hammock pulls flat-looking but the force climbs steeply — the same body weight now yanks on the straps and trees far harder. Go much steeper (saggier) and the force drops, but you sink into a deep, cocooning curve most people find less comfortable. Around 30° is the honest balance of comfort and load.
At 20°
×1.5
Half again as much — noticeably tighter
At 10°
×2.9
Nearly 3× — a lot to ask of hardware & bark
At 45°
×0.71
Lowest force — but quite saggy to lie in
Hang gently
Look after the trees that hold you
Those forces don't just test your gear — they press into 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 (1″) wide spread the load across the bark instead of biting into it. The wider the strap, the gentler the pressure — and the more secure your hang.
Never bare rope or thin cord
Rope, cord, wire or thin webbing cut into the bark under these forces and can girdle a tree — a ring of damage that can kill it. If it's narrow, it doesn't belong against the trunk.
Pick living, healthy trees
Choose two solid, living trees at least 15–20 cm thick (roughly a firm hug or thicker). Skip dead, leaning, cracked or hollow trunks — and never wrap a strap so tight it rings the whole trunk.
Leave no trace
Hang at a sensible height, keep the wrap high on a broad trunk, and take everything with you. Good habits keep these spots open — for the trees and for the next hammocker.
An honest note on the numbers
Static figures — real life bounces
These are static estimates: the steady pull when you lie still. The instant you climb in, shift, roll or bounce, the peak force spikes well above the number shown — sometimes by a large margin. Treat the calculator as a floor, not a ceiling.
So rate every part of your suspension with real headroom. Straps, carabiners, hooks and knots should be comfortably stronger than the static figure — the marked working load is your friend, not the breaking strength. When in doubt, hang a little slacker toward 30°, and check your hardware and knots before you trust them with your whole weight off the ground.
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