The fastest way to convert, calculate, format, and understand everyday numbers.
Fast browser-only converters, calculators, and formatting utilities. Each tool page includes formula notes, examples, and FAQs, with no fake placeholder pages in the index.
Live tools
cm to inches
Convert centimeters to inches using the exact 1 inch = 2.54 centimeters definition.
inches to cm
Convert inches to centimeters using the exact 1 inch = 2.54 centimeters definition.
kg to lbs
Convert kilograms to pounds using the exact definition 1 pound = 0.45359237 kilograms.
lbs to kg
Convert pounds to kilograms using the exact factor 1 pound = 0.45359237 kilograms.
C to F
Convert Celsius to Fahrenheit using the exact formula F = C x 9/5 + 32.
F to C
Convert Fahrenheit to Celsius using the exact formula C = (F - 32) x 5/9.
km to miles
Convert kilometers to miles using the exact relation 1 mile = 1.609344 kilometers.
miles to km
Convert miles to kilometers using the exact relation 1 mile = 1.609344 kilometers.
liters to gallons
Convert liters to US gallons using the exact relation 1 US gallon = 3.785411784 liters.
gallons to liters
Convert US gallons to liters using the exact relation 1 US gallon = 3.785411784 liters.
GST calculator
Add or remove GST at standard India rates with transparent base, tax, and total breakdown.
percentage calculator
Calculate percent of a number, percentage share, and percentage change in one page.
age calculator
Calculate exact age in years, months, and days between birth date and a target date.
word counter
Count words, characters, sentences, and paragraphs instantly in your browser.
JSON formatter
Format, minify, and validate JSON directly in your browser with instant error messages.
feet to meters
Convert feet to meters using the exact 1 ft = 0.3048 m definition.
meters to feet
Convert meters to feet using the exact 1 ft = 0.3048 m definition.
mm to inches
Convert millimeters to inches using the exact 1 inch = 25.4 mm definition.
inches to mm
Convert inches to millimeters using the exact 1 inch = 25.4 mm definition.
cm to feet
Convert centimeters to feet and inches — perfect for height (e.g. 170 cm).
feet to cm
Convert feet to centimeters using the exact 1 ft = 30.48 cm definition.
grams to ounces
Convert grams to ounces using the exact 1 oz = 28.349523125 g definition.
ounces to grams
Convert ounces to grams using the exact 1 oz = 28.349523125 g definition.
kg to stone
Convert kilograms to stone and pounds — the UK way to express body weight.
stone to kg
Convert stone to kilograms using the exact 1 stone = 6.35029318 kg definition.
mL to fl oz
Convert milliliters to US fluid ounces using the exact 29.5735295625 mL definition.
fl oz to mL
Convert US fluid ounces to milliliters using the exact 29.5735295625 mL definition.
km/h to mph
Convert kilometers per hour to miles per hour using the exact mile definition.
mph to km/h
Convert miles per hour to kilometers per hour using the exact mile definition.
sq ft to sq m
Convert square feet to square meters using the exact 0.09290304 m² definition.
sq m to sq ft
Convert square meters to square feet using the exact 0.09290304 m² definition.
gaj to sq ft
Convert gaj (square yard) to square feet — 1 gaj = 9 square feet.
sq ft to gaj
Convert square feet to gaj (square yard) — 9 square feet = 1 gaj.
degrees to radians
Convert degrees to radians using radians = degrees × π / 180.
radians to degrees
Convert radians to degrees using degrees = radians × 180 / π.
EMI calculator
Calculate loan EMI, total interest, and total payment from amount, rate, and tenure.
SIP calculator
Estimate the maturity value of a monthly SIP from amount, expected return, and duration.
Compound interest
See how an investment grows with compound interest over time.
Simple interest
Calculate simple interest and total amount from principal, rate, and time.
Discount calculator
Find the sale price and amount saved from a price and a percentage discount.
BMI calculator
Calculate Body Mass Index from weight in kilograms and height in centimeters.
Date difference
Find the gap between two dates in years, months, days, and total days.
Date calculator
Add or subtract days from a date to get the resulting date and weekday.
Hours calculator
Find the duration between two times, including overnight, in hours and minutes.
Base64 encode/decode
Encode text to Base64 or decode Base64 back to text, fully in your browser.
URL encode/decode
Percent-encode text for URLs or decode percent-encoded strings back to text.
Case converter
Convert text between UPPER, lower, Title, Sentence, camel, snake, and kebab case.
Character counter
Count characters, characters without spaces, and words with tweet and SMS limits.
Hex to RGB
Convert a hex color like #1d4ed8 to RGB values, with a live preview.
Number to words
Convert a number to words in the international or Indian (lakh/crore) system.
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How RapidUnits stays useful
We only index tools that are functional and tested. Conversion constants are explicit in source code, calculations run in your browser, and each page explains the formula behind the output.
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