Humble tools - big impact

Over the years, I've used my fair share of these little online tools — converting currencies, turning files or images from one format into another. And always with the same hope: free, no spam, no ads, no subscription wall.

Do you know the feeling? I bet you do. We've all been there at least once.

So I decided to build my own. With my teammate Claude, I generated a set of HTML apps that work flawlessly and do exactly what they promise — for free, with no spam and no subscriptions. You can bookmark them if you want to.

Free tools, no spam, ads or sub.

https://www.excelized.de/tools Convert almost anything—without uploading anything.

Just a single HTML file that runs entirely in the browser.

It fetches official daily reference rates from 84 central banks (via the open-source Frankfurter API), covers 200+ currencies, and drops straight into any webpage.

The best part? No infrastructure to maintain. No monthly bills. No signup walls. It just works.

Sometimes the cleanest solution isn't the most complex one — it's the one that does exactly what's needed and nothing more.

Currency converter, always available.

Another one is a multi-format file converter. Amazing tool, and more. Most file converters ask you to upload your data to someone else's server.

For client figures, personnel lists, or anything under an NDA, that's where the conversation ends.

So I built one that doesn't.

The Excelized Converter is a single HTML file. Open it, drop in a file, get a clean Excel, Word or PDF back. No upload. No account. No backend. Your file never leaves your device.

It reads what you actually have — xlsx, xls, ods, csv, docx, pdf, even photos and scans via OCR — and cleans up the usual mess along the way: trailing spaces, #DIV/0!, empty rows, numbers trapped as text.

The part I care about most: it's conservative by default.

→ Zeros are kept. A zero is usually a real measurement, not a placeholder.→ 01067 stays 01067. Postal codes don't get "helpfully" turned into 1067.→ Ambiguous formats like 1.234,56 are left alone rather than guessed at.

Anything genuinely lossy is off by default, with a warning about exactly what it will delete.

And every conversion appends a change summary inside the exported file — which options ran, how many cells were touched, which error tokens were cleared. Hand it to a colleague or an auditor and the provenance travels with it.

Client-side processing isn't a technical flourish. It removes a whole category of question: there's no data retention policy to read, because there's no server to retain anything.

Convert everything in something with the Excelized converter.

Last but not least, Drop a spreadsheet, get a dashboard.

I built a small tool that does one thing: you upload a CSV or Excel file, and it gives you an instant visual overview — KPIs, trend, breakdowns, sortable table.

The interesting part isn't the charts. It's the column mapping.

Real files don't have clean headers. "Umsatz", "Betrag", "Kostenstelle", "Ausschuss", "Mitarbeiter-ID" — the tool reads both the header name and the actual values to figure out what each column is. It handles German vs. English number formats (1.234,56 vs 1,234.56), currency symbols, and half a dozen date formats including Excel serials.

Then it shows you what it guessed, with a confidence score per column, and lets you override anything before building. Automatic where it can be, manual where it should be.

Everything runs in the browser. No server, no upload, no account. Your file never leaves your machine — which matters when the data is payroll or margins.

Exports as PNG, Excel report, or summary CSV.

It's a quick-look tool, not a BI platform. But for "what does this file actually say" — it answers that in about ten seconds.

InsightDrop, drop a file, get a dashboard.

Your thoughts on this one?

Free. Private. Browser-based.