The Three Temperature Scales
| Scale | Freezing Point | Boiling Point | Body Temp | Used In |
|---|---|---|---|---|
| Celsius (°C) | 0°C | 100°C | 37°C | India, Europe, most of world |
| Fahrenheit (°F) | 32°F | 212°F | 98.6°F | USA, Belize, Cayman Islands |
| Kelvin (K) | 273.15K | 373.15K | 310.15K | Science, physics, chemistry |
All Conversion Formulas
| Convert From → To | Formula | Example |
|---|---|---|
| Celsius → Fahrenheit | °F = (°C × 9/5) + 32 | 37°C → (37×1.8)+32 = 98.6°F |
| Fahrenheit → Celsius | °C = (°F − 32) × 5/9 | 98.6°F → (98.6−32)×0.556 = 37°C |
| Celsius → Kelvin | K = °C + 273.15 | 100°C → 373.15K |
| Kelvin → Celsius | °C = K − 273.15 | 300K → 26.85°C |
| Fahrenheit → Kelvin | K = (°F + 459.67) × 5/9 | 32°F → 273.15K |
| Kelvin → Fahrenheit | °F = K × 9/5 − 459.67 | 373.15K → 212°F |
Mental Math Tricks for Quick Conversion
Celsius to Fahrenheit — The Fast Approximation
Exact: (°C × 1.8) + 32. Approximate: (°C × 2) + 30
- 20°C: exact = 68°F, approximate = 70°F (close enough for weather)
- 30°C: exact = 86°F, approximate = 90°F
- 37°C: exact = 98.6°F, approximate = 104°F (too far off for medical — use exact)
The approximation works well for room temperature and weather (15–35°C range) but not for medical or extreme temperatures.
Fahrenheit to Celsius — Subtract 30, Halve
Quick approximation: (°F − 30) ÷ 2
- 68°F: (68−30)÷2 = 19°C (exact: 20°C) ✅
- 95°F: (95−30)÷2 = 32.5°C (exact: 35°C) — less accurate at higher temps
Quick Reference Conversion Table
| °C | °F | Context |
|---|---|---|
| −40 | −40 | Extreme cold — scales intersect here! |
| 0 | 32 | Water freezes / ice melts |
| 10 | 50 | Cold winter day in north India |
| 20 | 68 | Comfortable room temperature |
| 25 | 77 | Pleasant warm day |
| 30 | 86 | Hot Indian summer day |
| 37 | 98.6 | Normal human body temperature |
| 40 | 104 | Peak Indian summer / mild fever |
| 100 | 212 | Water boils at sea level |
| 180 | 356 | Common baking temperature |
| 200 | 392 | Higher baking temperature |
Temperature in Indian Cooking — Celsius & Fahrenheit
Many Indian recipes from international sources use Fahrenheit for oven temperatures. Here's a quick guide:
| Description | °F | °C | Typical Use |
|---|---|---|---|
| Very low | 250°F | 121°C | Slow cooking, dehydrating |
| Low | 300°F | 149°C | Slow roasting |
| Moderate | 350°F | 177°C | Cakes, cookies, bread |
| Moderately hot | 375°F | 190°C | Pastries, quick breads |
| Hot | 400°F | 204°C | Pizza, roasted vegetables |
| Very hot | 450°F | 232°C | Naan, artisan bread |
🌡️ Convert Any Temperature Instantly
Celsius, Fahrenheit, Kelvin — convert any temperature in seconds!
Convert Temperature →Frequently Asked Questions
Q: Why does the Celsius and Fahrenheit scale meet at −40?
The two scales intersect at exactly −40 because of their mathematical relationship. °F = (°C × 1.8) + 32. At −40: (−40 × 1.8) + 32 = −72 + 32 = −40. It's a mathematical coincidence of their specific definitions. At no other temperature do the two scales show the same number.
Q: What is absolute zero in Celsius and Fahrenheit?
Absolute zero is 0 Kelvin — the theoretical lowest possible temperature where molecular motion stops. In Celsius: −273.15°C. In Fahrenheit: −459.67°F. Nothing in the known universe has reached absolute zero, though scientists have achieved temperatures within billionths of a degree of it.
⚠️ Note
Temperature conversion formulas are standard mathematical conversions. Always use verified tools for scientific or medical applications.