UnitPrism
Convert anything.
Learn something.
Instant unit conversions across 10 categories — with real-world comparisons and a surprising fact every single time you visit.
✨ Surprising Fact
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Choose a category
Weight
kg · lb · g · oz · t
Distance
km · mi · m · ft · cm
Temperature
°C · °F · K · °R · °De
Volume
L · gal · mL · fl oz · cup
Speed
km/h · mph · m/s · kn · Mach
Area
m² · ft² · ac · ha · km²
Data
B · KB · MB · GB · TB
Time
s · min · h · d · yr
Pressure
Pa · bar · psi · atm · mmHg
Energy
J · kJ · kcal · cal · kWh
Currency
USD · EUR · GBP · JPY · +21 more
🧮 Calculators & Tools
Age Calculator
Years · months · days · heartbeats
Date Difference
Days · weeks · working days
Date Calculator
Add or subtract dates
Weekday Calculator
What day was any date?
Week Number
ISO week number for any date
Roman Numerals
Arabic ↔ Roman · 1–3,999
🔥 Popular conversions
kg → lbs
lbs → kg
km → miles
miles → km
feet → meters
°C → °F
°F → °C
liters → gallons
mph → km/h
GB → MB
TB → GB
hours → minutes
days → seconds
acres → hectares
atm → psi
kcal → kJ
USD → EUR
EUR → GBP
USD → INR
GBP → JPY
Age Calculator
Days between dates
Roman numerals
What day was it?
Mortgage payment
Compound interest
BMI check
💰 Finance Calculators
Make smarter money decisions — no spreadsheet required.
Mortgage
Monthly payment, amortization & total interest paid
Loan Calculator
Personal loan payments with full amortization schedule
Auto Loan
Car payment with tax, trade-in & true total cost
Compound Interest
Watch money grow — the 8th wonder of the world
Retirement
Project your nest egg & monthly retirement income
Inflation
Purchasing power over time — what was $1,000 really worth?
Salary Calculator
Convert between hourly, weekly, monthly & annual pay
Income Tax
2024 federal tax estimate with bracket breakdown
🏥 Health Calculators
Science-backed tools for understanding your body.