Converters
Turn any number into every unit at once — including fun ones like footsteps, blue whales, temperatures, and % of the speed of light.
📏 Length
mm1,000
cm100
m1
km0.001
in39.3701
ft3.2808
yd1.0936
mi0.0006214
nautical mi0.00054
footsteps1.3123
football fields0.01094
Eiffel Towers0.00303
📐 Area
sq cm10,000,000,000
sq m1,000,000
sq km1
sq in1,550,003,100.0062
sq ft10,763,915.0512
sq yd1,195,990.5612
acres247.1054
hectares100
sq mi0.3861
tennis courts3,832.8862
soccer fields140.056
🧊 Volume
mL1
L0.001
cubic cm1
cubic m0.000001
cubic in0.06102
cubic ft0.00003531
cubic yd0.000001308
tsp0.0002029
tbsp0.00006763
US cups0.004227
US gal0.0002642
bathtubs0.000006667
Olympic pools0.0000000004
⚖️ Mass
mg28,349.5
g28.3495
oz1
lb0.0625
kg0.02835
stone0.004464
tonnes0.00002835
US tons0.00003125
bananas0.2403
house cats0.0063
elephants0.000004725
blue whales0.000000189
🚀 Speed
m/s0.2778
ft/s0.9113
km/h1
mph0.6214
knots0.54
Mach0.0008098
% light speed0.00000009266
💾 Data
bits8,000
bytes1,000
KB1
MB0.001
GB0.000001
TB0.000000001
PB0.000000000001
photos (~3 MB)0.0003333
songs (~4 MB)0.00025
HD movies0.00000025
floppy disks0.0006944
⏳ Time
sec3,600
min60
hr1
days0.04167
weeks0.005952
fortnights0.002976
months0.001369
years0.0001141
decades0.00001141
centuries0.000001141
millennia0.0000001141
lifetimes0.000001521
🎈 Pressure
Pa1,000
hPa (mb)10
kPa1
bar0.01
psi0.145
atm0.009869
torr7.5006
inHg0.2953
mm H₂O101.9716
car tires0.004532
10 m seawater0.009948
🥄 Cooking
pinches16
dashes8
tsp (US)1
tbsp (US)0.3333
fl oz (US)0.1667
fl oz (UK)0.1735
jiggers0.1111
cups (US)0.02083
cups (metric)0.01972
cups (UK)0.01735
cups (Japanese)0.02464
pints (US)0.01042
pints (UK)0.008674
quarts (US)0.005208
L0.004929
mL4.9289
gal (US)0.001302
sticks butter0.04167
🌡️ Temperature
Celsius (°C)100
Fahrenheit (°F)212
Kelvin (K)373.15
Rankine (°R)671.67
Réaumur (°Ré)80
♨️ Past boiling — steam and hot-oven territory.
🏛️ Roman numerals
Type either a number or Roman numerals — it converts whichever way you need.
2,026=MMXXVI
How that adds up:
M1,000
M1,000
X10
X10
V5
I1
total2,026
Put a smaller symbol in front of a bigger one and you subtract it — that's why IX is 9, not 11.
M=1000 D=500 C=100 L=50 X=10 V=5 I=1
More number toys
Jump into another calculator.
🗓️ Date Calculator
The gap between any two dates — even billions of years.
⏱️ Cosmic You
Seconds alive, heartbeats, distance flown through space.
📅 Calendars
One day across the Gregorian, Maya, Islamic & more.
🔢 Big Numbers
How big is a billion? Every named number, written out.
♾️ Legendary Constants
π, e, φ, √2 & τ — endless digits, spirals & digit hunts.
🧬 Prime Lab
Factor numbers, GCD/LCM, primality & the Ulam spiral.
🚀 Speed & Distance
Light-travel times and how far to real places.
⚖️ Compare
You vs. a blue whale, a car vs. the speed of light.
🪐 Weight in Space
What you'd weigh on every planet, moon & black hole.
🔐 Cryptography
Scramble a message with a dozen ciphers — Caesar, Morse & more.
💻 How Computers Count
Binary, bytes & how a computer stores your words.
🎲 Random
Random numbers, dice & coins — with facts about every result.
📊 Probability & Odds
Birthday paradox, Monty Hall, dice curves & odds.