Yes. See [is Calcumber free](/blog/is-calcumber-free).

Is there a calculator that handles units properly?

Short answer

Yes — that is the specific problem Calcumber is built for. Give it an area in square inches and a paper weight in grams per square metre and it converts, checks that the dimensions make sense together, and returns a result that still carries its unit. The mistake it removes is the one that causes most quiet errors in engineering arithmetic: converting in your head and getting it wrong once, three lines up.

Why stripped units are where errors hide

When a tool cannot hold units, you convert everything to one system before you start and hope you kept it straight. The arithmetic is then correct and the answer is wrong, which is the worst failure mode there is — nothing in the output looks suspicious.

Keeping units in the calculation turns that silent error into a loud one. A dimensionally impossible step stops being a number you might publish and starts being a message you have to read.

Mentioned here: 🥒 Calcumber, 📚 Periodic Table, ➗ Calculator

What that looks like in practice

You write the quantity with its unit. You use it further down without thinking about the conversion. If you divide a mass by an area, the result is a mass per area and it says so. Change an input at the top and everything below recomputes with its units intact.

Fluid properties come from an integrated library rather than a table you retype, which removes the other classic transcription error.

Where it fits

It suits work where the units are the hard part: engineering, physical sciences, anything mixing metric and imperial. For plain arithmetic it is more machinery than you need.

It runs in the browser, installs like a desktop program and keeps calculating with no connection — see the Calcumber entry for the full record.