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grayscale · luminance · local

Convert any image to grayscale

Perceptual luminance weighting (Rec. 601) for natural-looking black-and-white output. Runs locally.

Grayscale Converter
Input
—
no file
Output
—
png
Formula
Rec.601
0.299·R + 0.587·G + 0.114·B
Status
waiting
pick file
input · image

image/* · runs locally · nothing uploaded

output · preview
Luminance formula: Y = 0.299·R + 0.587·G + 0.114·B
Alpha channel: preserved.
Color space: sRGB. Output: PNG (lossless).
No file yet.
Quick Start

How it works

Pick an image, tune the options, then download the result. Everything runs in your browser.

  1. 01

    Pick an image

    Any browser-decodable format works: PNG, JPEG, WebP, GIF.

    Files stay in memory as an HTMLImageElement — the original bytes are never uploaded, and EXIF metadata is preserved until you explicitly transform it.

    inputuploadcanvaslocaldecode
    input · bytesimage · loaded
    load: image/*
    loaded · decodedcanvas · ready
  2. 02

    Luminance weighting

    Each pixel is mapped to 0.299·R + 0.587·G + 0.114·B for perceptually balanced grays.

    Encoder quality is exposed where the format supports it — JPEG and WebP get a 0–1 quality slider; PNG is lossless. Options re-render the canvas immediately.

    mathoptionslive previewencoderquality
    weights · tunableRec.601 · live
    Y = 0.299R + 0.587G + 0.114B
    options applied · liveencoder · live
  3. 03

    Preserve alpha

    Transparent pixels stay transparent; only RGB is collapsed.

    Pixel work runs on the Canvas 2D context — drawImage resamples with the browser’s bilinear filter and getImageData/putImageData back per-pixel passes.

    alpharenderCanvas 2Dpreviewpx-perfect
    alpha · resampledkept · px-perfect
    A = unchanged
    preview · livepx-perfect
  4. 04

    Download PNG

    Lossless PNG output preserves the gray ramp without recompression artefacts.

    Downloads ship via a hidden anchor with an object URL — no server round-trip, and the file on disk is untouched. The output filename inherits a sensible suffix.

    exportdownloadblobclient-sideobject URL
    ok · blobready · saved
    gray.png
    shipped · ready to shipsuccess
Pro tips

Browser-only image work that scales

Convert with quality control

JPEG/WebP let you pick a 0–1 quality. Default 0.92 is a good compromise of size and visible quality.

PNG isn’t free

Use PNG only for transparency or sharp edges. For photos, WebP is smaller at the same perceived quality.

Strip EXIF for privacy

Photo EXIF often contains GPS, camera model, and timestamps. Strip before sharing public uploads.

Watch the colour profile

Convert to sRGB before web export. Wide-gamut images render oversaturated in non-managed browsers.

AVIF when it’s available

AVIF beats WebP on size at the same quality. Detect support via <picture> with fallbacks.

Lazy-load below the fold

Add loading="lazy" on <img>. The browser handles scheduling — no IntersectionObserver needed.

Related toolsInvert ColorsSepiaDuotoneBrightness/ContrastSaturationPosterize
Use Cases

When to use this tool

Common workflows it speeds up.

Editorial photos

Strip color for a clean, magazine-style look. Decoded into a Canvas 2D context — original bytes never leave the tab, so you can process customer-uploaded photos, internal screenshots, or sensitive diagrams without privacy concerns.

px-perfect

Avatar themes

Desaturated profile pics for muted UIs. Encoders expose quality 0–1 where the format supports it (JPEG, WebP); PNG and AVIF stay perceptually lossless. Pick 0.85 for web, 0.95 for archival, 0.7 for thumbnails.

quality-tunable

Print proofs

Preview how a page reads without color. Pair with the EXIF Stripper before sharing user-uploaded photos publicly. Camera serial numbers, GPS coordinates, and timestamps often hide in image metadata and leak more than the picture itself.

format-aware

ML training input

Single-channel feeders for image models. Output preserves colour profile (sRGB) so it renders consistently across browsers, monitors, and print pipelines. Wide-gamut workflows can opt into Display P3 for modern Apple devices.

EXIF-safe

Vintage look

Pair with sepia or grain for old-photo vibes. Re-runs only on option changes, never on window resize, so the canvas stays responsive on large images. drawImage uses the browser's bilinear filter for fast resampling.

client-side

Accessibility checks

See if a layout still works without color cues. Downloads as .png, .jpg, .webp, or .avif with the correct MIME so editors apply native handling on save. The filename inherits a sensible suffix derived from the input.

a11y
FAQ

Frequently asked questions

They approximate human-eye sensitivity better than a flat average, so green-heavy areas don't read too bright.
Yes — re-encoding through canvas discards EXIF and color profiles.
PNG keeps the gray ramp exact. JPEG would re-introduce compression noise.
Yes, the alpha channel is preserved bit-for-bit.
No. Everything runs locally in your browser.
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