About PDFtoLinks

What we do

PDFtoLinks builds small, free web tools that do one job well and get out of the way. There are no accounts to create, no trials, no paywalls and no feature tiers. Every tool works the moment the page loads.

The site began as a single utility for extracting hyperlinks from PDF documents, and has grown to include a collection of 24 calculators covering finance, health, mathematics and unit conversion.

Our tools

PDF Link Extractor

Reads a PDF and exports every hyperlink it contains to an Excel (.xlsx) spreadsheet. It is useful for auditing links in a report, collecting citations from a research paper, or pulling every URL out of a presentation.

Online Calculators

Loan and mortgage payments, compound interest, BMI, calorie needs, body fat, percentages, fractions, standard deviation, averages, age, date differences, GPA and unit conversion. Each shows its formula and explains the method, so the result can be checked rather than taken on trust.

How the tools work — and why it matters

Your files never leave your device. PDF extraction runs entirely inside your own browser using JavaScript. The document is read into memory, parsed locally, and the resulting spreadsheet is generated on your machine. Nothing is uploaded to a server, which means there is no queue, no file-size limit imposed by us beyond what your browser can handle, and no copy of your document anywhere but your own computer.

The calculators work the same way. The arithmetic happens in your browser as you type — the numbers you enter are never transmitted anywhere.

Accuracy

Every calculator states the formula it uses. Where a standard method exists we use it and name it — the Mifflin-St Jeor equation for energy expenditure, the U.S. Navy tape method for body composition, Bessel’s correction for sample standard deviation. Results are estimates for general information and are not financial, medical or legal advice.

Languages

The site is published in English only. Translated editions were withdrawn pending review by native speakers — a calculator that names the formula it uses has to name it correctly in every language it claims to speak, and machine translation is not good enough for that.

Contact

Questions, corrections and bug reports are all welcome — particularly corrections. If a calculator gives a result you believe is wrong, please get in touch and tell us the inputs you used.