About ToolFern
ToolFern is a one-person project: a free online toolkit for the small jobs that eat up ten minutes of everyone's day, converting a photo, splitting a PDF, working out a paycheck, sizing a solar battery. No team, no office, no venture funding. Just tools built, tested and kept current by me.
Why I started it
The first tool was a free HEIC to JPG converter, built because iPhone photos kept landing in my downloads folder in a format half the internet couldn't open. Every "free converter" I tried watermarked the result, capped the file size, or quietly uploaded my photos to a server I knew nothing about. A JPG conversion doesn't need a server round-trip; a modern browser can do the whole job on-device in under a second. So I built one that did, then kept going: an image compressor, a PDF merger, a paycheck calculator.
What ToolFern is today
ToolFern now runs 46 free online tools across 7 categories: image tools, PDF tools, finance and paycheck calculators, solar and energy calculators, text tools, everyday generators, and developer tools. Every tool does one job well instead of trying to be an all-in-one suite. If a tool doesn't do what its title says in under thirty seconds, that's a bug, not a feature.
How the tools work
Wherever the job allows it, the actual conversion, edit or calculation happens in your browser, not on a server, using your browser's own decoding and rendering engines. That's why the tools are fast and keep working on a weak connection, there's no server doing the processing for you to wait on. Separately, the file you pick and the result a tool produces are uploaded to storage so we can build a history you'll be able to see and redo from once accounts are live, details are in the Privacy Policy. The calculators (paycheck, mortgage, solar payback) run client-side too, using published formulas and current-year figures.
How the calculators stay accurate
The finance tools are rebuilt against the current tax year, not left to drift. The paycheck and payroll-tax calculators use the federal income tax brackets, standard deduction amounts, and Social Security/Medicare (FICA) wage limits published for the 2026 tax year, revisited whenever those figures change. I'm one person doing this by hand, not a licensed CPA or financial advisor, and every finance calculator says as much: built for quick estimates, not for filing your taxes. Found a figure that looks off? That's what the contact page is for.
How ToolFern stays free
Every tool is free, no account, no email, no watermark. That's funded by advertising, and occasionally affiliate links to products I think are genuinely useful, never by selling the tools or gating features behind a paywall. See the Privacy Policy for what that involves and the Affiliate Disclosure for how affiliate links work.
What's next
New tools ship regularly, usually because someone asked for them. Missing a converter, calculator or generator? The fastest way to get it built is to say so on the contact page. I read every message.