Everyday Tools
Handy region-agnostic utilities — age, scientific and statistics calculators, unit conversion, and JSON formatting. All free, no sign-up.
Percent of a number, share of a whole, percent change, and increase/decrease — with formulas.
Tip, total, and per-person share with one-tap percents, bill splitting, and round-up.
Find exact age in years, months, and days between any two dates.
Trigonometry, logarithms, powers, and constants for everyday and study use.
Compute mean, median, mode, variance, and standard deviation from a data set.
Convert length, weight, temperature, area, and more across common units.
Format, validate, and diff JSON, plus CSV and YAML conversion — live, with error line markers.
These are the utilities people reach for between the big financial decisions, built with the same care as the finance calculators: every tool shows its formula or method, works in both light and dark mode, and runs entirely in your browser with no sign-up. The percentage calculator handles the four questions people actually ask — percent of a number, share of a whole, percent change, and reverse percentages — each with the formula written out. The tip calculator adds bill splitting and round-up so a group can settle in one step, and the age calculator returns exact years, months, and days between any two dates — the same arithmetic used for eligibility cut-offs and paperwork.
For study and work there are full scientific and statistics calculators (the latter computes mean, median, mode, variance, and standard deviation from a pasted data set), a unit converter covering length, weight, temperature, area, and volume, and a JSON formatter and validator with clear error positions — handy when a config file breaks and you need to see where. Nothing you enter leaves your device.