Diamond painting drill count calculator
A 30 × 40 cm canvas with 2.5 mm drills holds 120 columns by 160 rows, or 19200 drills. Enter the painting size in cm, mm or inches, plus colors and a spare margin if you like, to size your order. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Canvas width
- 30
- Canvas height
- 40
- Canvas width mm
- 300 cm
- Canvas height mm
- 400
- Drill size mm
- 2.5
- Columns
- 120
Diamond painting covers an adhesive canvas with tiny resin drills, one colour at a time, until the printed chart becomes a sparkling mosaic. Before you order bulk bags or open a partial kit you need a reliable estimate of how many drills the canvas holds and, roughly, how many of each colour you might use. This diamond painting drill count calculator accepts the finished painting width and height in centimetres, millimetres, or inches, the centre-to-centre drill spacing in millimetres (defaults to 2.5 mm for common round and square resin drills), an optional colour count for an average-per-colour figure, and an optional spare percentage for loss and imbalance. It returns the millimetre canvas size, columns and rows that fit, total drill count, drills including spare, and when colours are provided the mean drills per colour. The path is pure finite arithmetic with no network calls, no random waste fudge, and no date-dependent shortcuts, so the same dimensions always produce the same grid plan.
What total drills and per-colour averages mean on a diamond canvas
A diamond painting canvas is a sticky grid printed with symbols; each cell receives one drill whose diameter or pitch is typically about two and a half millimetres for retail kits. When you know the finished width and height of the painting area—not the outer fabric border—you can convert those lengths into millimetres and divide by the drill spacing to count how many full columns and rows fit.
Multiplying columns by rows gives the total number of cells, which is the total number of drills required to fill the design without gaps. That total is the number kit makers quote as drill count on product pages and the number bulk buyers use when packing multi-gram bags. Real colour charts are not perfectly uniform: a sky may use thousands of light-blue drills while a thin outline uses only dozens of black ones.
When you supply a colour count, this calculator therefore reports the simple average total divided by colours, not a palette histogram, so you can size equal-share bags or decide whether a multipack of uniform bags is enough before you later refine counts from a legend spreadsheet. An optional spare percent lifts the shopping total with a ceiling on total times one plus spare over one hundred, matching the common practice of ordering ten to twenty percent extra for drops, colour swaps, and uneven distribution.
There is no brand database, no image upload that counts symbols from a photo, and no silent unit conversion mix-up: you choose centimetres, millimetres, or inches once, the engine converts only that choice into millimetres, floors the grid, and returns integers for columns, rows, and total.
What you can do with it
Custom canvas drill planning
Enter finished width and height plus drill spacing to get columns, rows, and total drills before you order bulk resin bags for a DIY diamond painting.
FAQ
What drill size should I use?
Most round and square resin drills are about 2.5 mm centre-to-centre, which is the default.
How is average drills per colour calculated?
Real charts are uneven; use the average for bulk planning, then refine from your legend if needed.
How many drills does a 30 × 40 cm canvas need?
With the usual 2.5 mm drills it needs 19200: 120 columns across and 160 rows down. Add a spare margin if you want extra drills for drops, color swaps and uneven use.
How much spare should I add to my order?
Many crafters order about ten to twenty percent extra to cover dropped drills, color swaps and charts where one color dominates. Enter that percentage and the total is rounded up to whole drills.
Should I measure the canvas with its border?
No. Measure only the finished painting area, not the outer fabric border, and use cm, mm or inches. That printed grid is what receives drills, so the border would inflate the count.
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-diamond-painting-drills \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"canvas_width":30,"canvas_height":40}'const res = await fetch("https://api.kit.forhosting.com/hobby/craft-diamond-painting-drills", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"canvas_width": 30,
"canvas_height": 40
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/hobby/craft-diamond-painting-drills",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"canvas_width": 30,
"canvas_height": 40
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/hobby/craft-diamond-painting-drills", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"canvas_width":30,"canvas_height":40}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"canvas_width":30,"canvas_height":40}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/hobby/craft-diamond-painting-drills", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"canvas_width": 30,
"canvas_height": 40
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "hobby.craft_diamond_painting_drills",
"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 total drills and per-colour averages mean on a diamond canvas
Round shopping bags up further at the store if bags are sold in fixed gram sizes; the API keeps the exact mathematical grid so automation stays reproducible.
Input contract, units, and how the grid stays reproducible
Computation uses floor division with a tiny epsilon so exact multiples such as three hundred millimetres over two point five millimetres become one hundred twenty columns without floating-point shortfall, then multiplies columns by rows as safe integers. Provide canvas_width and canvas_height as positive finite numbers in the same linear unit, then set unit to cm by default, mm, or in for the international inch of 25.4 millimetres. Optional drill_size_mm defaults to 2.5 when omitted; override it for square drills, larger cells, or mini canvases with a different pitch, always as a positive millimetre value. Optional color_count must be a positive integer when present and unlocks avg_drills_per_color in the response. Optional spare_percent must lie between zero and one hundred inclusive and defaults to zero so a pure fill count does not invent waste. Aliases such as width and painting_width for canvas width, height and painting_height for canvas height, drill_size and spacing_mm for drill size, colors and palette_size for colour count, and waste_percent or overage for spare percent are accepted so spreadsheets and typed forms can reuse the same contract. Missing width or height, non-positive geometry, unknown units, non-integer colour counts, and spare outside zero to one hundred fail with invalid_input naming the problem and are not billed. Pair the free browser run on this page with the priced API when a craft pipeline must emit the same drill count the designer saw on screen.
Where a diamond painting drill calculator earns its keep
Crafters meet this math when a custom canvas is printed at thirty by forty centimetres and the listing never states drill count, when a partial kit arrives with missing bags and you need a ceiling for reorders, or when you switch from round to square drills and want the same physical size recalculated with a new pitch. 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 drill bags, or to satisfy programming challenges that demand columns, rows, and total rather than a hand-waved guess. Classroom and workshop demos use the calculator when learners measure a canvas, choose two point five millimetre spacing, optionally enter forty colours and ten percent spare, and compare the predicted total against bags they already own. Kit designers and small shops can pre-generate total_drills and average-per-colour figures for modest rectangles without trusting opaque apps that silently switch units or add unstated waste. Product tools use the breakdown when a designer types width and height and the UI must show total drills next to drills_with_spare for a checkout estimate. 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 craft-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 craft helpers.
Integration use cases
Average drills per colour
Pass color_count with the canvas size to receive avg_drills_per_color for equal-share multipacks and rough palette budgeting.
Shop listings and craft software
Generate reproducible total_drills and drills_with_spare figures for product pages, kit specs, and pattern PDFs from the same pure grid math.
Technical questions
How do I calculate diamond painting drill count from canvas size?
Send canvas_width, canvas_height, and optional unit (cm default) and drill_size_mm (2.5 default). The API converts to millimetres, sets columns=floor(width_mm/drill_size_mm) and rows=floor(height_mm/drill_size_mm), and returns total_drills=columns×rows.
What does spare_percent do?
It adds a percentage buffer: drills_with_spare = ceil(total_drills × (1 + spare_percent/100)). Use 10–20 for loss and colour imbalance, or 0 for a pure fill count. Range is 0–100.
What does the diamond painting drill count calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.