Bias binding yardage calculator
A 60 by 80 quilt needs 290 of binding, and with 2.25-inch strips a fabric square 25.54408 on each side gives it as one continuous strip. No piecing dozens of short bits. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Project length
- 60
- Project width
- 80
- Strip width
- 2.25
- Binding length
- 290
- Fabric area
- 652.5
- Fabric square side
- 25.54408
- Fabric square diagonal
- 36.124784
Bias binding finishes curved and straight edges with a strip cut at forty-five degrees so the fabric stretches around corners without puckering. Quilters, garment sewers, and bag makers still need two numbers before they cut: how much binding the project consumes, and how large a fabric square will produce that continuous strip without piecing dozens of short segments. This bias binding yardage calculator accepts either finished project length and width plus an optional join allowance, or a direct binding length you already measured, together with the cut strip width. It returns the total binding length, the fabric area of the strip, the side of the continuous-bias square from the classic square-root identity, and the square diagonal for layout. The path is pure finite arithmetic with no network calls, no random waste fudge, and no date-dependent shortcuts, so the same inputs always produce the same yardage plan.
What bias binding length and the continuous square mean
Bias binding is a strip of fabric cut on the true bias so the grain runs diagonally across the strip; after folding it becomes a flexible edge finish for quilts, necklines, armholes, placemats, and bags. The linear length you need is usually the perimeter of the edges being bound plus a short join allowance for seams and finishing.
For a rectangular project that allowance is often about ten units in the same system as your measurements—ten inches for an inch-based quilt plan, for example—added to twice the sum of length and width. Once you know that total binding length and the cut width of the strip before folding, the continuous-bias method asks for a square of fabric whose area equals length times strip width.
The side of that square is therefore the square root of the product, and joining the square into a continuous tube or spiral yields one long strip without matching dozens of short bias pieces end to end.
Where bias binding yardage fits in sewing, quilting, and tools
Crafters meet this math when a quilt pattern lists finished size but not binding yardage, when a garment neckline needs bias from a small remnant, or when a bag maker wants continuous bias from a coordinated print without guessing the square. Pattern writers can pre-generate length and square-side figures for modest rectangles without trusting opaque apps that silently switch units or add unstated waste.
Classroom and workshop demos use the calculator when learners measure a quilt, add a join allowance, choose a strip width, and compare the predicted continuous square against fabric they already own. Product tools use the breakdown when a designer types length and width and the UI must show binding length next to the square side and diagonal for layout.
What you can do with it
Quilt binding from finished size
Enter quilt length and width plus strip cut width to get total binding length and the continuous-bias fabric square before you buy yardage.
FAQ
What units does the calculator use?
Any consistent linear unit—inches, centimetres, millimetres. Do not mix units in one request; the engine does not convert between systems.
Why is the fabric result a square side?
Continuous bias is commonly cut from a square whose area equals needed strip length times cut width, so side = √(length×width). Round up when shopping if fabric is sold in fixed increments.
How much bias binding do I need for a 60 by 80 quilt?
You need 290. That is twice the sum of 60 and 80, which is the perimeter, plus 10 for joining the ends and finishing the seams.
What size fabric square makes continuous bias binding?
Take the square root of binding length times strip width. For 290 at 2.25, that is a square 25.54408 on each side. Round it up at the cutting table if your shop sells fabric in fixed steps.
What strip width should I cut for bias binding?
Two and a quarter inches, 2.25, is a common cut for double-fold quilt binding, while garment bindings often use narrower strips. Enter the width before folding, in the same unit as your lengths.
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/hobby/craft-sewing-bias-binding \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"strip_width":2.25,"binding_length":290}'const res = await fetch("https://api.kit.forhosting.com/hobby/craft-sewing-bias-binding", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"strip_width": 2.25,
"binding_length": 290
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/hobby/craft-sewing-bias-binding",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"strip_width": 2.25,
"binding_length": 290
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/hobby/craft-sewing-bias-binding", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"strip_width":2.25,"binding_length":290}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"strip_width":2.25,"binding_length":290}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/hobby/craft-sewing-bias-binding", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"strip_width": 2.25,
"binding_length": 290
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "hobby.craft_sewing_bias_binding",
"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.
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
What bias binding length and the continuous square mean
This calculator returns binding_length, strip_width, fabric_area, fabric_square_side, fabric_square_diagonal, a length_source tag of perimeter or direct, the method continuous_bias_square, the precision used, and a short formula string you can quote in a pattern note. There is no brand fabric database, no automatic unit conversion between inches and centimetres, and no silent waste percentage: the engine multiplies and takes a square root inside a supported numeric range or rejects the input with invalid_input. Round the square side up at the cutting table if your shop sells fabric in fixed increments; the API keeps the exact mathematical side so automation stays reproducible.
Input contract, units, and how the numbers stay reproducible
Provide strip_width as a positive finite number in the same linear unit you use for lengths—two and a quarter inches is a common double-fold quilt cut, while garment bindings often use narrower strips. Supply either binding_length directly, or both project_length and project_width so the engine can compute binding_length as two times the sum of those dimensions plus join_allowance. The join_allowance field defaults to ten when you use the perimeter path and is ignored when you send binding_length; it must be non-negative when present. Aliases such as length and quilt_length for project length, width and quilt_width for project width, cut_width and bias_width for strip width, and length_needed or total_length for binding length are accepted so spreadsheets and typed forms can reuse the same contract. Optional precision, with aliases decimals and dp, chooses how many decimal places appear on every numeric field, defaulting to six and capped at fifteen so JSON goldens stay stable. Missing both a direct length and a complete dimension pair fails with invalid_input naming what is missing; zero or negative strip width, project dimensions, or binding length likewise fail with a clear positive-number message and are not billed. Pair the free browser run on this page with the priced API when a pattern pipeline must emit the same continuous-bias yardage the designer saw on screen.
Where bias binding yardage fits in sewing, quilting, and tools
Developers call the same contract from scripts to seed deterministic test vectors for craft calculators, to normalize user-entered dimensions before a storefront shows estimated fabric, or to satisfy programming challenges that demand fabric_area and fabric_square_side rather than a hand-waved guess. 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 KIT tier-A catalog and lets you move from a cutting-table plan to an automated pipeline without changing the mathematical result. Pair it with unit converters and other hobby endpoints when you are building a small lab of free, deterministic sewing helpers.
Integration use cases
Garment and bag edge finishes
Pass a measured binding_length for necklines, armholes, or bag openings and receive the square side needed for a continuous bias strip.
Pattern notes and craft software
Generate reproducible binding_length, fabric_area, and fabric_square_side figures for pattern appendices, PDFs, and shop product pages.
Technical questions
How do I calculate bias binding yardage for a quilt?
Send project_length, project_width, and strip_width (plus optional join_allowance, default 10). The API returns binding_length = 2×(length+width)+allowance and fabric_square_side = √(binding_length×strip_width).
What if I already know how much binding I need?
Send binding_length and strip_width directly. The perimeter fields are optional; fabric_square_side is still √(binding_length×strip_width).
What does the bias binding yardage calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.