Question 1

What is the HCODX Calculator Hub?

Accepted Answer

The HCODX Calculator Hub is a free collection of 100 in-browser calculators covering math, finance, health, conversions, dates, science and statistics. Every calculator runs entirely client-side — no upload, no signup, no tracking.

Question 2

Are these calculators free to use?

Accepted Answer

Yes. Every calculator is 100% free with no signup, no API key and no usage limits. The page itself is the entire app — open it offline and it still works once it's loaded.

Question 3

Do these calculators work on mobile?

Accepted Answer

Yes. The hub and every individual calculator are responsive — input grids collapse to single column on phones and the result panel scrolls cleanly. No mobile app required.

Question 4

Is my data sent to a server?

Accepted Answer

No. Every calculation happens in your browser via JavaScript. Inputs and results never leave your device, and no analytics are tied to individual values you enter.

Question 5

Which calculators are included?

Accepted Answer

Mortgage, loan, BMI, calorie, body-fat, retirement, compound-interest, scientific, GPA, time-card, days-between-dates, percentage, ratio, area, volume, fuel-cost and 80+ more — see the category tabs on the hub page for the full list.

PAYE Calculator — UK take-home 2025/26

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