Ever been confused by a 5.2 lb shipping weight on an overseas shopping site? Or wondered how many square feet a 33-pyeong Korean apartment is? Unit conversion is more common in daily life than you might think.
This guide covers the most frequently used conversion formulas for length, weight, temperature, area, data size, speed, pressure, and energy with practical examples.
📑 Table of Contents
1. Length Conversion
Length conversions are needed for monitor sizes (inches), travel (miles), and construction (feet).
| Conversion | Formula | Example |
|---|---|---|
| cm → inch | ÷ 2.54 | 170cm = 66.93in |
| inch → cm | × 2.54 | 27in = 68.58cm |
| ft → cm | × 30.48 | 5.9ft = 179.83cm |
| km → mile | × 0.6214 | 10km = 6.21mi |
Quick tip: To convert cm to feet/inches, divide by 2.54 to get total inches, then divide by 12 for feet. Example: 175cm ÷ 2.54 = 68.9in = 5'9".
📏 Length Converter Convert cm, inch, ft, m, km, and more →2. Weight Conversion
Weight conversions come up frequently in overseas shopping (lb), cooking (oz), and luggage limits (kg).
| Conversion | Formula | Example |
|---|---|---|
| kg → lb | × 2.2046 | 70kg = 154.32lb |
| lb → kg | × 0.4536 | 5.2lb = 2.36kg |
| oz → g | × 28.3495 | 8oz = 226.80g |
Quick tip: To estimate lb → kg, halve the lb value and subtract 10%. Example: 7.5lb ÷ 2 = 3.75, minus 10% ≈ 3.4kg (actual: 3.40kg).
⚖️ Weight Converter Convert kg, lb, oz, g, and more →3. Temperature Conversion
Korea uses Celsius while the US uses Fahrenheit. Key formulas:
| Conversion | Formula | Example |
|---|---|---|
| °C → °F | (°C × 9/5) + 32 | 36.5°C = 97.7°F |
| °F → °C | (°F − 32) × 5/9 | 350°F = 176.7°C |
| °C → K | °C + 273.15 | 0°C = 273.15K |
Common reference points: Water freezes at 0°C (32°F), body temperature is 36.5°C (97.7°F), and water boils at 100°C (212°F). For oven baking, 350°F ≈ 177°C.
🌡️ Temperature Converter Convert between Celsius, Fahrenheit, and Kelvin →4. Area Conversion
In Korea, pyeong (평) is still widely used for real estate despite m² being the official unit. 1 pyeong = 3.3058 m².
| Korean Term | m² | ft² |
|---|---|---|
| 18 pyeong | 59.50 | 640.44 |
| 25 pyeong | 82.64 | 889.54 |
| 33 pyeong | 109.09 | 1,174.23 |
5. Data Size Conversion
Understanding data units is essential in the digital age. Note that manufacturers use SI (decimal: 1KB = 1,000 bytes) while operating systems use binary (1KiB = 1,024 bytes) — which is why a "1TB" drive shows as ~931GB.
| Unit | SI (Decimal) | IEC (Binary) |
|---|---|---|
| 1 KB | 1,000 B | 1,024 B (KiB) |
| 1 MB | 1,000 KB | 1,024 KiB (MiB) |
| 1 GB | 1,000 MB | 1,024 MiB (GiB) |
| 1 TB | 1,000 GB | 1,024 GiB (TiB) |
6. Speed, Pressure & Energy
Speed
Key conversions: 1 km/h = 0.6214 mph, 1 m/s = 3.6 km/h. Korea's highway speed limit of 110 km/h equals about 68 mph.
Pressure
Tire pressure is typically 32-35 psi (2.2-2.4 bar / 220-241 kPa). 1 atm = 101,325 Pa = 14.696 psi.
Energy
The daily recommended intake of 2,000 kcal equals 8,368 kJ. For electric bills, 1 kWh = 3.6 MJ. European food labels often show kJ alongside kcal.