ForHosting KIT · Developer Utilities

Rafter overhang length calculator

This rafter overhang length calculator converts a horizontal eave projection into the extra rafter length you must add when framing a roof overhang.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Carpenters measure the run past the wall plate on the plan, but the board is cut on the slope, so the tail is longer than the horizontal distance by the same pitch factor used on the main common rafter. Enter the horizontal overhang and the pitch as rise per twelve units of run; the engine multiplies the projection by the square root of one plus the unit-rise squared and returns the along-slope rafter overhang plus the vertical drop over that tail. A classic check uses a twenty-four unit horizontal projection with a six-twelve pitch, which yields about twenty-six point eight units of stock after the pitch-factor step. Both inputs must share the same linear unit—inches, feet, or metres—because the engine never converts units for you. The work is pure deterministic arithmetic with no network calls, no sampling, and no date-dependent shortcuts. Use it free in the browser for framing take-offs and DIY eave tails, or call the API at $0.002 per successful request when you need reproducible overhang lengths inside estimating software, spreadsheets, or CI fixtures.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

How do I use this capability?

Complete the fields above and run it on this page. The form highlights anything that needs attention.

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

POSThttps://api.kit.forhosting.com/home/rafter-overhang

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/home/rafter-overhang \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"overhang":24,"pitch":6}'

const res = await fetch("https://api.kit.forhosting.com/home/rafter-overhang", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "overhang": 24,
    "pitch": 6
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/home/rafter-overhang",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "overhang": 24,
    "pitch": 6
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/home/rafter-overhang", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"overhang":24,"pitch":6}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"overhang":24,"pitch":6}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/home/rafter-overhang", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "overhang": 24,
  "pitch": 6
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "home.rafter_overhang",
  "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

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

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.

Read the full KIT documentation →