Two types of calorimeters developed to measure energy in high‐power laser pulses are described: solid‐absorber calorimeters, of designs capable of extension to large diameters, and stirrred‐liquid calorimeters. Results are given for measurements of 1.06 &mgr; pulses at power densities up to about 1011W cm−2. The calorimeters are calibrated by electrical heating; together with measurements of the specular reflection and thermal radiation losses, this permits performance of absolute measurements to an accuracy of better than 1%.