The EXCALIBUR (Experimental x-ray CALIBration UseR) facility at General Atomics is a versatile x-ray tool supporting diverse research needs not covered by commercial instruments. It enables synchrotron-grade x-ray metrology in a compact, lab-based system. Designed for fast, high-precision measurements, it supports the calibration of x-ray crystals, filters, and target components used in high-energy-density physics and plasma experiments. EXCALIBUR features a 30 kV x-ray tube, NIST calibrated silicon drift detector, x-ray Cameras, and a suite of automated instruments and analysis scripts. Areal density, opacity, and spectral responses measurements can be completed routinely with the capability to measure matrix of points on a single sample or 10 s of samples per day with photon energy range of 1–17 keV. These measurements have 1% repeatability and ∼1%–5% accuracy limited by the current opacity databases. EXCALIBUR’s breakthrough capability lies in its ability to calibrate crystals in a benchtop lab-base measurement therefore allowing more accessibility to the community. Crystal calibrations cover photon energies from ∼600 eV to 20 keV with ∼10% uncertainty. These measurements are essential for the development and validation of experimental plasma diagnostics. Demonstrations involving opacity measurements of Cu–Mg–SiO2 foil, gas cell opacity benchmarks of Argon, and Quartz (Qz) transmission crystals are presented.