Hammock hang calculator
Two trees 12 feet apart with a 30-degree sag call for straps just under 3.5 feet above the hammock's lowest point. Enter the anchor spacing and the sag angle you want, and get the mounting height and how much line each side uses. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Spacing
- 12
- Angle
- 30
- Half span
- 6
- Mounting height
- 3.4641016151
- Hang distance
- 6.9282032303
- Strap height
- 3.4641016151
This hammock hang calculator turns the distance between two anchors and the sag angle you want into the mounting height, strap height, and hang distance you should set before you wrap the first tree strap. Campers, backyard nappers, and outfitters use it so a gathered-end hammock sits at a comfortable thirty-degree hang instead of a banana-tight ridge or a sag that scrapes the ground. The engine models each side of the hang as a right triangle: half the anchor spacing is the adjacent side, the sag angle is measured from the horizontal, mounting height is the opposite side, and hang distance is the hypotenuse of that half-span.
How spacing and angle are read so results stay reproducible
Optional leading plus signs and scientific notation on numeric strings are allowed when they parse as finite decimals; embedded spaces, hex prefixes, and non-numeric tokens are rejected with a message that names the field so a bad cell does not become a wrong wrap mark. Angle must also sit strictly below ninety degrees, because a vertical or past-vertical strap is not a sag hang — tangent and cosine stop describing a downward triangle at that wall.
Typical backyard hangs use twelve to eighteen feet between healthy trees and twenty-five to thirty-five degrees of sag; the classic gathered-end advice is thirty degrees, which makes mounting height a little under three tenths of the tree gap. Both fields share one length unit for the whole request: feet, metres, or centimetres, as long as you do not mix them. Computation uses ordinary floating-point trigonometry, then rounds each numeric field to ten decimal places so goldens stay stable across runtimes.
Where hammock-hang planning fits in camping, teaching, and software
People meet hammock-hang math when two backyard maples are fourteen feet apart and nobody can say whether the straps should wrap at eye height or at a belt, when a first-night camper pulls the ridgeline drum-tight and then wonders why sleep is miserable, or when a teacher wants a trigonometry word problem that is not a ladder against a wall.
Shoppers can pre-check a twelve-foot gap at thirty degrees before they treat a new pair of straps as a sunk cost, and outfitters can compare a shallow twenty-degree hang against a deep thirty-five-degree lounge without opaque forum macros. Contest and homework practice often needs a fast, offline source of hang numbers so solutions can be checked without a tape in the woods under time pressure.
Product and education tools use the split when a learner types a tree distance and the interface must show a clean wrap height beside the echoed inputs. Pair it with a cable-tension or sagitta helper when you are assembling a small lab of free, deterministic sag-planning tools, and keep this page for the hammock-hang search itself.
What you can do with it
Set tree straps before the first night out
Turn the measured gap between two healthy trees and a thirty-degree sag target into mounting height and hang distance before you wrap the straps.
Homework and outdoor-club trigonometry
Generate a reproducible right-triangle hang from spacing and sag angle, including the half-span, tangent drop, and cosine hypotenuse.
FAQ
How do I calculate hammock hang height from tree spacing?
Send a positive spacing between anchors and a positive sag angle in degrees from the horizontal.
What sag angle should I use for a gathered-end hammock?
The classic hang is 30 degrees from the horizontal. Shallower angles (around 20–25) sit flatter and need more strap; steeper angles (around 35) drop more and feel more nested. Any positive angle strictly below 90 is accepted.
What is hang distance versus mounting height?
Mounting height is the vertical drop from the wrap to the hammock low point. Hang distance is the length of each hang line — the hypotenuse of that same half-span triangle. Add your preferred ground clearance to mounting height when you mark the tree.
What happens if spacing or angle is zero or negative?
A hang needs a positive gap and a positive sag angle; a missing tape reading is not treated as a valid wrap height and is not billed.
How far apart should the trees be for a hammock?
Typical backyard hangs use twelve to eighteen feet between healthy trees. Measure the gap first: at a 30-degree sag the straps sit a little under three tenths of that distance above the hammock's lowest point, so a wider gap needs a higher wrap.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/life/hammock-hang \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"spacing":12,"angle":30}'const res = await fetch("https://api.kit.forhosting.com/life/hammock-hang", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"spacing": 12,
"angle": 30
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/life/hammock-hang",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"spacing": 12,
"angle": 30
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/life/hammock-hang", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"spacing":12,"angle":30}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"spacing":12,"angle":30}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/life/hammock-hang", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"spacing": 12,
"angle": 30
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "life.hammock_hang",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Limits
max_abs_value | 1000000000000000 |
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Every input must be a positive finite number — zero, a negative tape reading, or a ninety-degree or steeper angle is rejected as invalid_input so a missing measurement is not treated as a valid wrap height. Run it free in the browser for a campsite check, or call the API at $0.002 per successful request when a packing list, classroom demo, or rental script needs the same figure.
What a hammock-hang result means and what the response contains
A hammock-hang result is the geometry of a symmetric two-line hang between two trees, posts, or stand ends: how high to attach the straps above the lowest point of the fabric, and how much line each side of the hang actually uses. It is not a catenary of the occupied cloth, and it is not a shopping count of whoopie slings: it is the right triangle that hammock hangers have used for decades when they say “hang at thirty degrees.” This calculator answers that with a closed form. half_span is spacing divided by two, the horizontal run from one anchor to the centre of the hang. mounting_height is half_span times the tangent of the sag angle, the vertical drop from the wrap to the hammock low point — that is the number you add to your preferred ground clearance when you mark the tree. hang_distance is half_span divided by the cosine of the same angle, the length of each hang line from the wrap down to the centre. strap_height is the same as mounting_height, so a form that asks for strap wrap height and a script that asks for mounting height read one figure. total_suspended_length is spacing divided by cosine of the angle, the full path from one wrap to the other along both hypotenuses. The response echoes the two normalized inputs, returns those derived fields, and includes a method tag symmetric_sag_triangle plus a formula string so a spreadsheet or a test can repeat the same steps without guessing. There is no hidden stretch factor, no ridgeline length, and no soil-clearance adder: the engine either applies tan and cos to two finite positive numbers or it rejects the input with invalid_input.
How spacing and angle are read so results stay reproducible
The preferred field for the gap between anchors is spacing, but aliases anchor_spacing, tree_distance, distance, and trees are accepted so a form, a query string, or a spreadsheet column can reuse the same contract without renaming cells. Angle prefers angle, with aliases sag_angle, hang_angle, and degrees; the unit is degrees from the horizontal, not from the tree trunk and not radians. Both values must be strictly greater than zero: that is the product contract, and a missing, zero, or negative tape reading is invalid_input. Pair the free browser run on this page with the priced API when you need that identical mathematical result inside an automated packing list or rental pipeline without re-implementing the triangle yourself.
Where hammock-hang planning fits in camping, teaching, and software
Developers call the same contract from scripts to seed deterministic test vectors for outdoor calculators, to normalize user-entered tree gaps before a gear demo, or to satisfy a product statement that demands mounting_height, hang_distance, and strap_height fields rather than a hand-waved “hang it high.” On this page the work runs entirely in your browser; through the API each successful lookup costs $0.002, failed validation is not charged, and nothing is stored after the response returns. That split — free interactive exploration and a priced, identical API — matches the rest of the tier-A catalog and lets you move from a campsite demo to an automated pipeline without changing the mathematical result.
Integration use cases
Outfitter quotes and packing-list scripts
Normalize backyard or stand spacing into strap_height and total_suspended_length so a rental desk or a gear checklist uses one figure.
Technical questions
What does the hammock hang calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.