SM Arijul Islam

What I do here

UnitCalConv is a site I built and maintain. My work on it is practical rather than academic: I choose which converters and calculators are worth publishing, check the factors and formulas behind them against the defining standard, write the explanation that sits around each tool, and handle the error reports that arrive through the contact page.

That means most days involve reading a standard rather than writing prose. A conversion factor is only as good as its source, so the first question on any page is where the number comes from: the BIPM SI Brochure for SI units, NIST Special Publication 811 for US customary conversions, and the relevant national agency or professional body where a measure is defined outside SI.

How the pages are checked

Each formula is recalculated by hand against at least two worked examples before a page is published. The examples are chosen to catch the errors that are easy to miss — a zero or negative input, a unit at the edge of the supported range, a conversion run in both directions, or a case that should round. The interactive tool and the reference table on the page are built separately, so a mistake in one is unlikely to be repeated in the other.

Converter pages use exact definitions where they exist: 1 inch is exactly 25.4 mm, 1 pound is exactly 0.45359237 kg, 1 mile is exactly 1.609344 km. Calculators that depend on a convention rather than a constant — cup sizes, marla, mesh openings, yarn counts, grading scales — say which convention they use and where it varies by country or trade.

The full process, including the source hierarchy, review schedule and correction policy, is published in the editorial standards.

What I do not claim

I am not a doctor, a solicitor, a financial adviser or a structural engineer, and nothing here is professional advice. Health pages cite the World Health Organization, the CDC, the NHS and the Dietary Guidelines for Americans; finance pages cite the Consumer Financial Protection Bureau; education pages state that grading scales are institution-specific. Those citations are there so you can check the basis of a result yourself, not because the site speaks for those bodies.

The tools are built to be accurate and useful, but they are aids to a decision rather than a substitute for one. Where a result could matter — a dose, a loan, a load-bearing span — confirm it with the qualified person or the current standard that applies to your situation.

Corrections

An error report is the most useful message the site receives. If a conversion is wrong, tell me the page, the value and units you entered, the result you saw and the result you expected; a reference to a standard or a manufacturer's data sheet makes it certain. Confirmed arithmetic errors are fixed promptly and the page's review date moves forward. If the disagreement is about a convention rather than a mistake, the page is amended to explain which convention it uses.

Use the report an error form. Reports are read by me, not filed into a queue.

Elsewhere on the site

See the About page for how the site is funded and run, the editorial standards for the full process, and the guides for the longer explanations behind the tools.