Convert Microjoules to Calories
Convert Microjoules (µJ) to Calories (cal) instantly and accurately.
Conversion Formula
cal = µJ × 2.390057361e-7
About Microjoules
A microjoule (µJ) is 10⁻⁶ J - the scale of precision laser ablation, ESD damage events, and individual LIDAR pulses. LASIK eye surgery delivers 0.5-2 µJ per pulse at 193 nm, ablating ~0.25 µm of corneal tissue per pulse. ESD events that destroy IC gates correspond to 1-1,000 µJ; the Human Body Model test discharges ~500 µJ at 2 kV. Q-switched microchip laser pulses for rangefinding are 1-100 µJ. The kinetic energy of a 1 mg grain of sand falling 10 cm is mgh ≈ 0.98 µJ. 1 µJ = 10⁻⁶ J.
About Calories
A calorie (cal) - the thermochemical calorie - is exactly 4.184 J, defined as the heat to raise 1 g of water by 1°C. Standard since 1954. The calorie is the fundamental unit of heat measurement in thermochemistry: glucose combustion releases 669.9 kcal/mol; water vaporisation requires 539.7 cal/g. Bond dissociation energies in quantum chemistry are often quoted in kcal/mol. Note: the dietary Calorie (capital C) on food labels is 1 kcal = 4,184 J - a factor-of-1,000 difference that causes persistent confusion. 1 cal = 4.184 J = 1.163 × 10⁻³ Wh.
Quick Reference Table
| Microjoules (µJ) | Calories (cal) |
|---|---|
| 1 µJ | 2.39 × 10-7 cal |
| 2 µJ | 4.78 × 10-7 cal |
| 5 µJ | 1.195 × 10-6 cal |
| 10 µJ | 2.39 × 10-6 cal |
| 25 µJ | 5.975 × 10-6 cal |
| 50 µJ | 1.195 × 10-5 cal |
| 100 µJ | 2.39 × 10-5 cal |