Smart, free calculators – no sign‑up, no ads, just instant answers.
Basic arithmetic: add, subtract, multiply, divide.
Tip, discount, % change, and more.
Calculate simple & compound interest.
Final price after markdown.
Split bill & add gratuity.
Hourly to yearly, net pay estimator.
Compare value & find the best buy.
Monthly installment & amortization.
CAGR, SIP calculator, future value.
Exact years, months, days from birthdate.
Body Mass Index & health category.
Daily calorie needs (Harris‑Benedict).
Estimate using tape measurements.
Recommended daily water intake.
Healthy weight range for your height.
Estimate from last period or conception.
Target zones for fat burn & cardio.
Trig, log, exponents, roots.
Length, weight, volume, temperature…
Convert percentages instantly.
Test if a number is prime.
Roots of ax²+bx+c=0.
Area, perimeter, sides & angles.
Area, circumference, diameter.
Convert numbers ↔ Roman numerals.
°C ↔ °F ↔ K.
HEX ↔ RGB ↔ HSL.
Binary, Hex, Octal, Decimal.
Days, weeks, months between dates.
Convert between any time zone.
Acres, ares, hectares, cm², ft², in², m²…
mm, cm, m, km, in, ft, yd, mi, nm, mil.
UK gal, US gal, L, ml, cm³, m³, in³, ft³.
Tons, UK tons, US tons, lb, oz, kg, g.
Bits, bytes, KB, KiB, MB, MiB, GB, GiB…
ms, sec, min, hr, day, week.