Lembog is a collection of free online tools for everyday tasks: calculators, converters, text and code utilities, and PDF and image tools. It's built and maintained by Mazil Khatib, and has been growing since 2023.
What you'll find here
There are 282 tools, grouped by what they do:
- Calculators (96): finance, health, maths, statistics and dates
- PDF tools (4): merge, split, and convert between PDF and images
- Generators (68): passwords, QR codes, fancy text and random data
- Converters (39): units, colours, number systems and file formats
- Formatters (9), encoders and decoders (5) and validators (5) for developers
- Lookup tools (3) for IP addresses, DNS and domain registration
- Translators (3) and utilities (50) for text, images and everything else
You can also search every tool by name.
How the tools work
Most tools run entirely in your browser. When you format JSON, merge PDFs or convert an image, the work happens on your own device and your data is never uploaded to Lembog. That makes the tools fast, lets them keep working on a poor connection, and makes them safe for private documents.
A few tools can only work by asking an outside service. The IP, DNS and WHOIS lookups, for example, query public internet registries. Each of these is listed, with the service it uses, in the privacy policy.
How we keep results right
Each tool page explains what the tool does, how to use it, and where its limits are. Newer tools, such as the mortgage calculator, PDF tools and DST file converter, also show the formula or method behind the result and a worked example, so you can check the answer yourself. We're adding the same detail to older pages over time.
Calculators give estimates for planning. For decisions about health, money or legal matters, check the result with a qualified professional.
Found a mistake?
If a tool gives a wrong result, breaks, or explains something incorrectly, please tell us through the contact page or at [email protected]. Include the tool's name, what you entered, and what you expected to see. Corrections are made as quickly as possible.
How Lembog is funded
Every tool is free, with no sign-up and no paid version. The site is funded by ads served by Google AdSense. Ads never change how a tool works or what result it gives. You can read how advertising cookies are used, and how to opt out, in the privacy policy.