Calculators that know where you live.
Country-aware rules, transparent formulas and browser-only calculation. Official-data tools cite primary sources; every tool is free and requires no account.
Categories
Find the tool you need by topic
Featured tools
A hand-picked starting point across everyday tasks
Percentage Calculator
Ratios, increase/decrease
CalculatorsLoan Calculator
Monthly payment, total interest
CalculatorsCompound Interest Calculator
Final balance, total interest, contributions
CalculatorsAge Calculator
Age in years, months, days
Date & TimeDays Until Calculator
Days until a date or between two dates
Date & TimeUnit Converter
Length, weight, temperature
ConvertersTemperature Converter
Celsius, Fahrenheit and Kelvin — live conversion
ConvertersBMI Calculator
Body mass index & healthy weight
HealthCalorie Calculator
BMR and daily calorie needs (TDEE)
HealthWord Counter
Words, characters, sentences, paragraphs, reading time
OfficeCharacter Counter
Characters, words, lines and UTF-8 bytes
OfficePassword Generator
Random secure passwords, strength check
DeveloperQR Code Generator
Text or URL to a QR code, download as PNG
OfficeImage Compressor to KB
Compress a photo to an exact KB target (20/50/100/200KB)
OfficeData Storage Converter
Convert between Bit, Byte, KB, MB, GB, TB, PB
ConvertersTime Converter
Convert between ms, s, min, h, day, week, month, year
ConvertersScientific Calculator
Trig, log, sqrt, powers and more
CalculatorsAverage Calculator
Mean, median, min, max, sum from a list of numbers
CalculatorsWhy use utilduck
Completely free
Every tool is free with no registration.
Private by design
Calculator inputs are not submitted to utilduck servers. Analytics, ads and browser-provided features follow the Privacy policy.
Instant results
Real-time calculation as you type.
Mobile friendly
Works cleanly on phones, tablets, and desktops.
Accurate formulas
Standard formulas with the reasoning explained.
Educational
Understand the math behind each result.
All calculators provide estimates for reference only. Actual results may vary. Consult a professional before important decisions.