Calculate the ideal distance, height, and sag angle for hanging a hammock. Covers tree spacing, hardware needs, and comfort optimization.
There's a science to hanging a hammock comfortably. Too tight and it squeezes you like a taco. Too loose and you sink to the ground. The sweet spot — recommended by experienced hammock campers and the physics of catenary curves — is a 30° hang angle from horizontal, with a sit height of about 18 inches.
This calculator computes the exact anchor point heights, strap lengths, and sag depth based on your tree/post spacing and the hammock length. The key relationship is trigonometric: for a given distance between anchors and hammock length, the hang angle and sag are mathematically determined by the ridgeline length (distance between attachment points when the hammock is hung).
Whether you're hanging a backyard hammock between trees, setting up anchor posts, or planning a hammock camping setup, this tool provides all the measurements — anchor heights, strap lengths needed, weight capacity considerations, and hardware recommendations. It even handles the common problem of trees that aren't the ideal distance apart.
Use this calculator when you want a comfortable hang without repeated trial-and-error at the campsite or in the backyard. It is useful for choosing anchor height, checking tree spacing, and avoiding the overly tight setup that makes hammocks uncomfortable and stresses the suspension. That makes setup faster when you are dealing with uneven trees or limited spacing.
Ridgeline length ≈ hammock length × 0.83 (for 30° angle). Anchor height = sit height + sag depth. Sag = distance × tan(hang angle) ÷ 2. Required strap length = √(half-distance² + height²) − (distance ÷ 2). Hang angle = arctan(2 × sag ÷ distance).
Result: Anchor at about 5.8 ft high, with a deep 30° hang and about 52" of sag
With 15 ft between trees and a 30° hang angle, the sag works out to about 4.33 ft. Adding an 18-inch sit height puts the anchors near 5.8 ft high. The exact strap length depends on how much of the suspension is taken up by the hammock body, loops, and tree wraps.
A hammock under load follows a catenary curve — the same shape as a hanging chain. The tension at the anchor points equals your weight divided by (2 × sin(hang angle)). At 30°, a 200 lb person creates about 200 lbs of force on each anchor. At 15° (too tight), the same person creates 386 lbs of force — nearly double. This is why tight hangs are uncomfortable and stress hardware.
The 30° hang angle was popularized by Derek Hansen (author of "The Ultimate Hang"). At this angle, the hammock curves enough to lie flat on the diagonal axis, distributes weight evenly along the fabric, and creates a comfortable sitting position. The ridgeline (the effective distance between suspension points) is approximately 83% of the hammock length at 30°.
A structural ridgeline is a cord running between the two ends of the hammock at a fixed length. Once set to ~83% of your hammock length, it maintains the same sag regardless of how far apart your trees are. This is the single best upgrade for consistent comfort — you adjust straps for height and angle, but the sag stays perfect.
The consensus among experienced hammock campers is 30° from horizontal. This creates a comfortable sag that's deep enough to lie flat diagonally but not so deep that you feel trapped. Angles between 25-35° work well; below 20° is too tight, above 40° is too saggy.
Ideal spacing is 13-16 feet for a standard 10-11 foot hammock. Too close (under 10 ft) and the angle is too steep. Too far (over 20 ft) and you need very long straps or bigger hammock. The calculator handles non-ideal spacing.
Typically 4.5-6 feet high, depending on distance between anchors and desired sit height. The further apart the anchors, the higher they need to be to maintain the same hang angle. Our calculator provides the exact height.
If the ground slopes, measure the horizontal distance. If trees are different diameters, the strap wraps will be different lengths. You can adjust one side's anchor height to compensate for slopes — the calculator assumes level ground.
Quality hammock straps are rated 400-1000+ lbs. Use tree-friendly straps at least 1" wide to avoid bark damage. For hammocks supporting 2 people, use straps rated for 500+ lbs. Never use thin rope — it can cut into bark and kill trees.
Yes. If the sit height is below 14-16 inches, getting in and out is difficult, and the hammock may touch the ground when you sit (the sag increases significantly under load). 18 inches is the standard recommended sit height.