About SizeKit
SizeKit is a small, free collection of practical tools: a photo resizer for upload limits, eight everyday calculators and converters, and guides that explain how they work.
Why SizeKit exists
Many forms reject a perfectly good photo because it is a few kilobytes too large or the wrong number of pixels. SizeKit started as a way to fix that quickly, without uploading a personal photo to a stranger’s server. The calculators and converters came from the same idea: small everyday tasks that should not need an account, an app or a page full of clutter.
What you can do here
- Photo resizer: set a maximum file size in KB and pixel dimensions, then download a JPG or WebP.
- Calculators and converters: percentage, percentage change, discount, BMI, age, length, weight and height.
- Guides: explanations, worked examples and common mistakes for each topic.
Who made SizeKit?
SizeKit was created by Haris Asif and is operated by Haris Asif / SYX AI. It is an independent project. Questions, corrections and suggestions are welcome through the contact page.
How the tools work
When you pick a photo, your browser opens and processes it. SizeKit draws it at your chosen dimensions and adjusts the JPG or WebP quality to fit the maximum file size. If it cannot fit, it shows an error rather than quietly changing your dimensions. The tool does not send the photo to an image-processing server or save it in an online account. Calculators run in your browser too, and nothing you type into them is sent anywhere. The website itself is delivered by Cloudflare, so loading pages involves ordinary network requests, and the built-in sample image is fetched from the site when you choose it.
What SizeKit is not
- It is not a medical, legal, financial or professional service. Results are for general information. See the disclaimer.
- It cannot certify that a photo meets an official specification or that a website will accept it.
- It does not crop photos, remove backgrounds, convert HEIC files or create PDFs.
How we write and check the guides
Guides that cover official photo rules, such as visa, passport and lottery uploads, are written from the issuing agency's own instructions, and we tell you to check that page before you submit because rules change. Calculator guides show the formula and a worked example so the answer can be confirmed by hand. We would rather say "check your form" than promise that a file will be accepted.
See it work
The homepage includes a real before-and-after example. The built-in sample photo started at 233.2 KB and 1600 × 1067 pixels, and with an 800-pixel width and a 100 KB limit the JPG result was 94.0 KB at 800 × 534 pixels. Results vary with the image and browser, so always preview the file you download.
Corrections and updates
Pages were last reviewed in October 2026. If a photo requirement, formula or explanation is wrong or out of date, email hello@sizekit.pro and we will check it and update the page.
How the site is funded
SizeKit is free to use. The site may show advertising from Google AdSense to cover running costs. Ads, where they appear, are provided by Google and are separate from the tools. SizeKit does not sell your data and does not accept payment to change what a tool or guide says.
Our standards
Every tool page shows the formula it uses and a worked example you can check by hand. Guides are written to answer a real question and say plainly where a result can mislead. If you find an error, tell us and we will correct it.
Credits
The built-in sample photo is by Annie Spratt on Unsplash, used under the Unsplash License.