Deadweight tester calibration involves verifying and adjusting the accuracy of a deadweight tester, which is considered one of the most precise primary standards for pressure measurement. The process includes inspecting and cleaning the piston-cylinder assembly, checking weight sets for accuracy, and ensuring the system generates the correct pressure based on applied masses and local gravity. During calibration, the tester’s output is compared against certified reference equipment to confirm performance across its pressure range. Regular calibration ensures the deadweight tester maintains its role as a reliable pressure standard, supports traceability, meets regulatory and industry requirements, and guarantees accurate calibration of other pressure instruments.