OntoEase provides a full suite of browser-based unit converters covering metric, imperial and scientific units. All formulas below use standard SI bases and widely accepted coefficients so results are precise and reliable for students, engineers, developers and everyday users.

Length & Distance Conversion Standards (SI Base Unit: Meter)

• 1 millimeter (mm) = 1 × 10⁻³ meters (m)
• 1 centimeter (cm) = 1 × 10⁻² meters (m)
• 1 kilometer (km) = 1 × 10³ meters (m)
• 1 inch (in) = 0.0254 meters (m)
• 1 foot (ft) = 0.3048 meters (m)
• 1 yard (yd) = 0.9144 meters (m)
• 1 mile (mi) = 1,609.344 meters (m)
• 1 nautical mile (nmi) = 1,852 meters (m)
• 1 micrometer (µm) = 1 × 10⁻⁶ meters (m)
• 1 nanometer (nm) = 1 × 10⁻⁹ meters (m)
• 1 Astronomical Unit (AU) = 1.495978707 × 10¹¹ meters (m)
• 1 light-year (ly) = 9.4607 × 10¹⁵ meters (m)

Mass & Weight Conversion Standards (SI Base Unit: Kilogram)

• 1 gram (g) = 1 × 10⁻³ kilograms (kg)
• 1 milligram (mg) = 1 × 10⁻⁶ kilograms (kg)
• 1 microgram (µg) = 1 × 10⁻⁹ kilograms (kg)
• 1 carat (ct) = 2 × 10⁻⁴ kilograms (kg)
• 1 ounce (oz) = 0.0283495 kilograms (kg)
• 1 pound (lb) = 0.45359237 kilograms (kg)
• 1 stone (st) = 6.35029318 kilograms (kg)
• 1 metric ton (t) = 1,000 kilograms (kg)
• 1 short ton = 907.18474 kilograms (kg)
• 1 long ton = 1,016.0469088 kilograms (kg)

Temperature Conversion Equations (SI Base: Kelvin)

• Celsius (°C) to Fahrenheit (°F) = (°C × 9/5) + 32
• Fahrenheit (°F) to Celsius (°C) = (°F − 32) × 5/9
• Celsius (°C) to Kelvin (K) = °C + 273.15
• Kelvin (K) to Celsius (°C) = K − 273.15
• Fahrenheit (°F) to Kelvin (K) = (°F + 459.67) × 5/9
• Kelvin (K) to Rankine (°R) = K × 9/5
• Rankine (°R) to Kelvin (K) = °R × 5/9
• Réaumur (°Ré) to Celsius (°C) = °Ré × 5/4
• Delisle (°D) to Celsius (°C) = 100 − (°D × 2/3)
• Newton (°N) to Celsius (°C) = °N × 100/33
• Rømer (°Ro) to Celsius (°C) = (°Ro − 7.5) × 40/21

Time Conversion Standards (SI Base Unit: Second)

• 1 minute (min) = 60 seconds (s)
• 1 hour (h) = 3,600 seconds (s)
• 1 day (d) = 86,400 seconds (s)
• 1 week (wk) = 604,800 seconds (s)
• 1 month ≈ 2,592,000 seconds (s)
• 1 year (yr) = 31,536,000 seconds (s)
• 1 decade = 315,360,000 seconds (s)
• 1 century = 3,153,600,000 seconds (s)
• 1 millisecond (ms) = 1 × 10⁻³ seconds (s)
• 1 microsecond (µs) = 1 × 10⁻⁶ seconds (s)
• 1 nanosecond (ns) = 1 × 10⁻⁹ seconds (s)

Volume & Capacity Conversion Standards (SI Base: Cubic Meter)

• 1 milliliter (mL) = 1 × 10⁻⁶ cubic meters (m³)
• 1 liter (L) = 1 × 10⁻³ cubic meters (m³)
• 1 teaspoon (tsp) = 4.92892 × 10⁻⁶ cubic meters (m³)
• 1 tablespoon (tbsp) = 14.7868 × 10⁻⁶ cubic meters (m³)
• 1 cup ≈ 240 × 10⁻⁶ cubic meters (m³)
• 1 US gallon (gal) = 3.785411784 liters (L)
• 1 UK gallon (gal) = 4.54609 liters (L)
• 1 quart (qt) = 0.946352946 liters (L)
• 1 pint (pt) = 0.473176473 liters (L)
• 1 barrel (bbl) = 0.1589872949 cubic meters (m³)

Area Conversion Standards (SI Base: Square Meter)

• 1 square centimeter (cm²) = 1 × 10⁻⁴ square meters (m²)
• 1 square kilometer (km²) = 1 × 10⁶ square meters (m²)
• 1 square inch (in²) = 6.4516 square centimeters (cm²)
• 1 square foot (ft²) = 0.09290304 square meters (m²)
• 1 square yard (yd²) = 0.83612736 square meters (m²)
• 1 square mile (mi²) = 2.58999 square kilometers (km²)
• 1 hectare (ha) = 10,000 square meters (m²)
• 1 acre (ac) = 4,046.8564224 square meters (m²)

Speed & Velocity Conversion Standards (SI Base: Meter per Second)

• 1 kilometer per hour (km/h) = 0.277778 meters per second (m/s)
• 1 mile per hour (mph) = 0.44704 meters per second (m/s)
• 1 knot = 0.514444 meters per second (m/s)
• mph to km/h = multiply by 1.60934
• km/h to mph = multiply by 0.621371
• Mach (20 °C) ≈ 343 meters per second (m/s)
• Speed of sound (air) ≈ 343 m/s
• Speed of light = 299,792,458 m/s

Digital Storage & Data Transfer Standards (Base: Byte)

• 1 byte (B) = 8 bits (b)
• 1 kilobyte (KB) = 1,000 bytes (B)
• 1 megabyte (MB) = 1,000,000 bytes (B)
• 1 gigabyte (GB) = 1,000,000,000 bytes (B)
• 1 terabyte (TB) = 1,000⁴ bytes
• 1 kibibyte (KiB) = 1,024 bytes (B)
• 1 mebibyte (MiB) = 1,024² bytes
• 1 gibibyte (GiB) = 1,024³ bytes
• 1 tebibyte (TiB) = 1,024⁴ bytes
• MB to GB = divide by 1,000
• MiB to GiB = divide by 1,024
• MBps to Mbps = multiply by 8

Energy Conversion Standards (SI Base: Joule)

• 1 kilojoule (kJ) = 1,000 joules (J)
• 1 calorie (cal) = 4.184 joules (J)
• 1 kilocalorie (kcal) = 4,184 joules (J)
• 1 watt-hour (Wh) = 3,600 joules (J)
• 1 kilowatt-hour (kWh) = 3.6 × 10⁶ joules (J)
• 1 electron-volt (eV) = 1.602176634 × 10⁻¹⁹ joules (J)
• 1 BTU ≈ 1,055.05585 joules (J)

Electricity Conversion Standards (Ohm’s Law & Power Formula Index)

• Ohm’s Law: Voltage (V) = Current (I) × Resistance (R)
• Current (I) = Voltage (V) ÷ Resistance (R)
• Resistance (R) = Voltage (V) ÷ Current (I)
• Electrical Power: Watt (W) = Voltage (V) × Current (A)
• Ampere (A) to milliampere (mA) = multiply by 1,000
• mA to A = divide by 1,000
• kW to W = multiply by 1,000
• W to kW = divide by 1,000

Pressure Conversion Standards (SI Base Unit: Pascal)

• 1 kilopascal (kPa) = 1,000 pascals (Pa)
• 1 bar = 100,000 pascals (Pa)
• 1 standard atmosphere (atm) = 101,325 pascals (Pa)
• 1 PSI = 6,894.76 pascals (Pa)
• 1 torr = 133.322 pascals (Pa)
• 1 mmHg = 133.322 pascals (Pa)
• 1 inHg = 3,386.39 pascals (Pa)

Density Conversion Standards (SI Base Unit: Kilogram per Cubic Meter)

• 1 g/cm³ = 1,000 kg/m³
• 1 lb/ft³ = 16.0185 kg/m³
• kg/m³ to g/cm³ = divide by 1,000
• g/cm³ to kg/m³ = multiply by 1,000

Force Conversion Standards (SI Base Unit: Newton)

• 1 kilonewton (kN) = 1,000 newtons (N)
• 1 pound-force (lbf) = 4.4482216152605 newtons (N)
• newtons (N) to kN = divide by 1,000

Angle Conversion Standards (SI Base Unit: Radian)

• 180 degrees (°) = π radians (rad)
• 1 degree (°) = π/180 radians (rad)
• Radians (rad) to degrees (°) = multiply by 180/π
• 1 gradian (gon) = 0.9 degrees
• 400 gon = 360 degrees = 2π radians

Frequency & Bandwidth Conversion (SI Unit: Hertz)

• 1 kilohertz (kHz) = 1,000 hertz (Hz)
• 1 megahertz (MHz) = 1,000,000 Hz
• 1 gigahertz (GHz) = 1 × 10⁹ Hz
• GHz to MHz = multiply by 1,000
• MHz to Hz = multiply by 1,000,000

Acceleration Conversion Standards (SI Unit: m/s², Gravity Index: g-Force)

• 1 standard gravity (g-force) = 9.80665 m/s²
• m/s² to g-force = divide by 9.80665
• g-force to m/s² = multiply by 9.80665

Fuel Consumption & Vehicle Efficiency Conversion

• Miles per gallon (mpg US) to kilometers per liter (km/L) = multiply by 0.425144
• km/L to mpg US = divide by 0.425144
• Liters per 100 km (L/100km) to km/L = 100 ÷ (L/100km)
• km/L to L/100km = 100 ÷ (km/L)
• mpg Imperial to km/L = multiply by 0.354006

Construction, Material and Scientific Conversion References

• Cubic yard to cubic meter = multiply by 0.764554857984
• Square foot to square meter = multiply by 0.09290304
• Degree (°) to radian (rad) = multiply by π/180
• Radian (rad) to degree (°) = multiply by 180/π
• Acceleration (m/s²) to g-force = ÷9.80665
• g-force to m/s² = ×9.80665
• GSM (Textile) stays in g/m² as industry standard
• Mach number depends on medium: Mach 1 at 20 °C ≈ 343 m/s