Thomas Asenjo

Thomas Asenjo

I build and maintain ToolkitHQ: the calculators, the guides, and the words on every page. I’m a software developer based in Victoria, Australia, and this site is a solo project — there is no content team behind the byline and no ghostwriter to pass the buck to.

Background

I’ve spent my working life building software tools, which is where the habit behind this site comes from: if a question has a definite arithmetic answer, it should not require an account, a pop-up, or a paywall to reach. Most of what I know about finance, construction estimating, and nutrition formulas comes from building the tools themselves — working out the formula, checking it against a reliable source, and testing it against real examples until the numbers hold up.

How I work

Every calculator is hand-written in plain JavaScript and runs in your browser. The explanatory content is researched and drafted with the help of AI, then checked by me against the formula the calculator actually runs and against the sources named on the page. That combination is deliberate: AI is useful for producing clear explanations at scale, and useless for knowing whether an amortization schedule or an R-value calculation is correct. The checking is the part that matters, and it’s the part I do.

I set the standards for how that works on the methodology page and the editorial policy, and I apply them to every guide and tool page. When I get something wrong, I correct it and say so — the fastest way to reach me is below.

Why ToolkitHQ exists

The calculator sites I kept landing on were either buried under ads or locked behind a sign-up wall, and the good ones were often thin on explanation — you got a number with no way to check it. ToolkitHQ is the opposite bet: small, fast, no account, and every result explained well enough that you can see where it came from. If a calculator can’t be built properly, I’d rather leave it out than pad the catalogue.

Get in touch

Found an error, disagree with a result, or want a tool or guide that doesn’t exist yet? Email [email protected]. A reproducible error in a calculation gets fixed as a priority, and the correction is noted on the page.

ToolkitHQ is operated as a sole trading business: Thomas William Diego Asenjo, ABN 25 303 258 251, Victoria, Australia.