Complementary room color scheme
Start from a wall colour such as #6B8E9F and get a pale trim #E4E6E6 in the same hue plus a contrasting accent #9E6E56 from the opposite side of the colour wheel. Paste a paint chip code and sample all three. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Wall color
- #6B8E9F
- Scheme
- #6B8E9F, #E4E6E6, #9E6E56
- Scheme roles
- wall, trim, accent
- Harmony
- complementary
- Hue rotation deg
- 180
Choosing paint for a room is rarely only about the wall colour. Baseboards, door casings, crown moulding, and a feature accent all need to sit in a coherent relationship so the space feels designed rather than improvised. This complementary room color scheme tool takes the primary wall hex you already like, applies classical colour-harmony rules in HSL space, and returns a ready-to-sample trim colour plus an opposite-hue accent for furniture, art walls, or small architectural details. Homeowners, interior stylists, and renovation planners can paste a brand chip or photo-sampled hex and receive deterministic wall, trim, and accent bundles with RGB and CSS strings. Malformed colour codes fail with a clear invalid input error instead of a silent clamp.
Wall input and how the complementary room scheme is built
Hex may be three or six hexadecimal digits with or without a leading hash, so both #6B8E9F and 6B8E9F work, as do short forms such as #69f and 69f. Case is ignored. After the digits are expanded to six uppercase characters, the colour is converted from sRGB channels into hue, saturation, and lightness using the standard max-min-chroma path shared with CSS graphics stacks.
From that wall HSL triple the algorithm derives two companion roles. Trim keeps the same hue as the wall so architectural lines feel related to the field colour, then lowers saturation into a pale tint band and raises lightness into the high eighties or mid nineties when walls are medium or dark—the classic “tinted white trim” pattern used by paint manufacturers. When the wall is already very light, lightness above seventy-five percent, trim instead deepens into a darker same-hue edge so casings still read against pale plaster.
Accent takes the complementary step: hue rotates by one hundred eighty degrees on the wheel, saturation is boosted slightly so the accent reads as a deliberate focal note, and lightness is inverted then clamped into a paint-usable band between twenty-five and seventy-five percent so neither washed-out pastels nor near-black blocks appear by accident. Trim and accent HSL values convert back to integer RGB and six-digit hex.
Using the scheme in a real renovation
Call the free in-browser complementary room color scheme tool while standing in a store aisle or reviewing contractor proposals without installing a design suite. Pair the returned accent with lighting and fabric samples in person—hex harmony is a structural starting point, not a substitute for viewing chips under your room’s north or south light. Chain scheme hex values into printouts, PDF proposals, or design-token pipelines that keep wall, trim, and accent labelled for multi-room projects.
Authors shipping SDKs can map wall.hex, trim.hex, and accent.hex directly into swatch components or CSS custom properties without reimplementing HSL conversion and architectural trim rules in every language. Keep requests small, document the complementary harmony rule to end users so they know accent is opposite-hue by design, and you get reproducible room palettes for DIY blogs, contractor tools, and edge workers without standing up a full colour-management stack of your own.
What you can do with it
DIY room repaint planning
Paste the wall hex from a favourite chip or photo sample and receive matching trim and complementary accent colours before buying gallons.
Paint store and e-commerce configurators
Online paint pickers return a three-role scheme so shoppers leave with wall, casing, and accent recommendations in one click.
FAQ
How do I suggest a complementary room color scheme from a wall hex?
The response includes wall, trim, and accent objects plus a scheme array of the three hex codes.
How is the trim colour chosen?
Trim keeps the wall hue, lowers saturation into a pale tint, and uses high lightness for mid or dark walls. If the wall is already very light (lightness ≥ 75%), trim deepens so casings still contrast against pale walls.
How is the accent colour chosen?
Accent uses complementary harmony: hue rotates by 180°, saturation is boosted slightly, and lightness is inverted then clamped into a 25–75% band suitable for paint accents.
Is the complementary room color scheme tool free?
The browser tool runs free on your device.
Does it work with grey or very light walls?
Yes. A grey wall still gets an accent with a clear hue, so you can add a controlled note of colour. On a very light wall the trim turns into a deeper shade of the same hue so the casings stay visible.
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/paint-color-room-match \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"wall_color":"#6B8E9F"}'const res = await fetch("https://api.kit.forhosting.com/life/paint-color-room-match", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"wall_color": "#6B8E9F"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/life/paint-color-room-match",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"wall_color": "#6B8E9F"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/life/paint-color-room-match", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"wall_color":"#6B8E9F"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"wall_color":"#6B8E9F"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/life/paint-color-room-match", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"wall_color": "#6B8E9F"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "life.paint_color_room_match",
"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
Wall input and how the complementary room scheme is built
Send a JSON field named wall_color with a CSS hex string. The engine also accepts the aliases color, hex, wall, and primary so forms and SDKs can reuse familiar names. The full path is pure arithmetic with no network, no random seed, and no wall clock, so identical wall colours always produce identical JSON.
Reading wall, trim, accent, and the scheme array
Use wall for large field surfaces, trim for baseboards, window surrounds, and ceiling lines, and accent for a single feature wall, built-ins, or soft furnishings that need contrast without fighting the wall field. Grey walls with near-zero saturation still receive a complementary accent hue rotation; the accent may show hue change even when the wall itself looks neutral, which is intentional so you can introduce a controlled colour note. A successful response echoes wall_color as the normalised six-digit hex with a leading hash, then expands three role objects named wall, trim, and accent. Each role object carries role, hex, hex_digits without the hash, integer r g b channels, h s l components in degrees and percent, an rgb_css string such as rgb(107, 142, 159), and an hsl_css string for design tokens. The scheme array lists the three hex codes in wall-trim-accent order, and scheme_roles labels those slots for clients that map colours into UI chips without hard-coding order. Fields harmony and hue_rotation_deg document the rule in force—complementary and one hundred eighty—while method is always room_complementary_trim_accent and formula restates the trim and accent construction in one line for docs and support. Empty strings, non-hex characters, wrong digit lengths, and missing wall_color all fail with invalid_input and are not charged after the engine rejects the request. Prefer this endpoint when search intent is a room paint scheme with trim and accent; for a single opposite swatch without interior roles use the complementary color finder elsewhere in the catalogue, and for multi-hue theory palettes see triadic or tetradic generators.
API usage, pricing, renovation workflows, and practical limits
POST a compact JSON body with wall_color set to your primary wall hex. Use the prepaid API when a renovation planner, paint e-commerce configurator, property staging app, or mood-board generator needs a stable contract under KIT balance at $0.002 per successful item; validation failures never consume balance after the engine rejects the request.
Integration use cases
Staging and renovation proposals
Stagers and contractors embed deterministic wall-trim-accent hexes in proposals and CI fixtures that never drift between environments.
Technical questions
What happens if the wall color format is invalid?
The request fails with invalid_input. Empty values, non-hex characters, wrong digit length, and missing wall_color are rejected and not charged.