Convert Calories to Microjoules

Convert Calories (cal) to Microjoules (µJ) instantly and accurately.

Conversion Formula

µJ = cal × 4184000

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.

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.

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