Free Converter Tools Online

Convert between 100+ units across 12 categories: length, weight, temperature, volume and more.

Full-featured scientific calculator with trig functions, logarithms, history and memory.

Calculate exact age in years, months, days, hours and seconds. Includes birthday countdown and zodiac sign.

Convert time between world timezones. Compare multiple zones with business hours indicator.

Convert numbers to Roman numerals and Roman numerals to numbers. Supports 1–3,999,999 with batch conversion.

Calculate percentages: X% of Y, percentage change, discount, tax, and percentage difference. 5 modes.