Resize Image Size to an Exact KB or Pixel Target in Seconds

Resizer Lab is a free online image resizer built to resize image size in KB or pixels — by custom size or preset, without losing quality.

Published January 1, 2025 · Last updated August 3, 2026

Key takeaway (TL;DR)

In short: to resize an image size in KB or pixels, upload your photo, enter the width and height (or pick a preset), set a target file size or quality, then download. Bottom line: it takes about 10 seconds, is 100% free, needs no signup, and every image is processed in your browser — nothing is ever uploaded to a server.

• Cost: free, unlimited, no signup or watermark.
• Speed: ~10 seconds per image, instant download.
• Privacy: 100% browser-based, zero uploads.
• Formats: JPG, PNG and WebP, resized by pixels, percentage or KB.

Sources & references

• Client-side scaling is defined in the MDN Web Docs reference for CanvasRenderingContext2D.drawImage().
• Smoothing behaviour follows the W3C HTML Canvas 2D Context specification.
• WebP files average roughly 25–34% smaller than comparable JPEGs, per Google's WebP Compression Study.
• Quality settings of 70–85 cut file size with little visible loss, per web.dev — Choose the correct level of compression.
• Passport presets follow the U.S. Department of State photo requirements.