41 free worldwide calculators — country-aware for tax and banking, universal for health, dates, units and math.
Monthly payment + total interest
PITI: principal + interest + tax + insurance
US / UK / AU / MY — net pay after tax
Hourly ↔ monthly ↔ annual
UK / AU / SG / MY property duty
30+ countries with standard rates
Annual tax with US-state presets
Investment growth + contributions
I = P × r × t
Nest egg with inflation adjustment
Total return + annualized (CAGR)
Country-aware tipping + bill split
Body Mass Index + WHO category
Daily calorie burn at rest + active
US Navy tape-measure formula
Daily target for any goal
Daily hydration target
From last menstrual period
Fertile window + cycle phase
Years, months, days, next birthday
Time between any two dates
Business days minus holidays
Add or subtract years/months/days
IANA TZ-aware, DST handled
Live timer to any future date
m, km, mi, ft, in, yd, nmi
kg, lb, oz, tonne, stone
°C, °F, K
L, mL, gal (US/UK), cup, pt
m², ft², acre, hectare
mph, km/h, m/s, knot, mach
J, kWh, cal, kcal, Btu
Pa, kPa, bar, atm, psi, mmHg
KB/MB/GB/TB — decimal & binary
4 common forms in one tool
sin, cos, log, sqrt, powers, π, e
+ − × ÷ & auto-simplify
Mean, median, mode, std dev
Events, coin flips, dice
All calculators run entirely in your browser. The country-aware ones (income tax, VAT/GST, stamp duty, tip) auto-detect your country and apply local rules, but you can switch to any supported country with one click.
Tax data is sourced from official government publications and updated periodically. These are estimates only — consult a qualified accountant for decisions with real money on the line.