  We summarize the outcome of the 10th meeting of the International
Astronomical Consortium for High Energy Calibration (IACHEC), held in Beijing
(People's Republic of China) in April 2015. Over 80 scientists directly
involved in the calibration of operational and future high-energy missions
gathered during 3.5 days to discuss the status of the X-ray payload
inter-calibration, as well as possible ways to improve it. A recent study on a
large sample of galaxy clusters confirmed that the calibration of the effective
area shape above 2 keV between XMM-Newton/EPIC and Chandra/ACIS is consistent,
but showed a significant discrepancy at lower energies. Temperatures measured
by EPIC are therefore smaller, the difference being largest for the highest
temperatures, up to ~20% at kT=10 keV (Schellenberger et al. 2015). The latest
multi-mission study of the Crab Nebula above 10 keV shows a +/-13% agreement in
the relative normalization of the INTEGRAL, NuSTAR, RXTE, and {\it Suzaku} hard
X-ray instruments.

Instrumentation and Methods for Astrophysics