arrow_back_ios

Main Menu

See All Acoustic End-of-Line Test Systems See All DAQ and instruments See All Electroacoustics See All Software See All Transducers See All Vibration Testing Equipment See All Academy See All Resource Center See All Applications See All Industries See All Insights See All Services See All Support See All Our Business See All Our History See All Our Sustainability Commitment See All Global Presence
arrow_back_ios

Main Menu

See All Actuators See All Combustion Engines See All Durability See All eDrive See All Production Testing Sensors See All Transmission & Gearboxes See All Turbo Charger See All DAQ Systems See All High Precision and Calibration Systems See All Industrial electronics See All Power Analyser See All S&V Hand-held devices See All S&V Signal conditioner See All Test Solutions See All DAQ Software See All Drivers & API See All nCode - Durability and Fatigue Analysis See All ReliaSoft - Reliability Analysis and Management See All Test Data Management See All Utility See All Vibration Control See All Acoustic See All Current / voltage See All Displacement See All Load Cells See All Pressure See All Strain Gauges See All Torque See All Vibration See All LDS Shaker Systems See All Power Amplifiers See All Vibration Controllers See All Accessories for Vibration Testing Equipment See All Training Courses See All Articles See All Acoustics See All Asset & Process Monitoring See All Custom Sensors See All Data Acquisition & Analysis See All Durability & Fatigue See All Electric Power Testing See All NVH See All Reliability See All Smart Sensors See All Vibration See All Weighing See All Automotive & Ground Transportation See All Calibration See All Installation, Maintenance & Repair See All Support Brüel & Kjær See All Release Notes See All Compliance See All Our People
arrow_back_ios

Main Menu

See All CANHEAD See All GenHS See All LAN-XI See All MGCplus See All Optical Interrogators See All QuantumX See All SomatXR See All Accessories See All BK Connect / Pulse See All API See All Microphone Sets See All Microphone Cartridges See All Acoustic Calibrators See All Special Microphones See All Microphone Pre-amplifiers See All Sound Sources See All Accessories for acoustic transducers See All Experimental testing See All Transducer Manufacturing (OEM) See All Accessories See All Non-rotating (calibration) See All Rotating See All CCLD (IEPE) accelerometers See All Charge Accelerometers See All Impulse hammers / impedance heads See All Cables See All Accessories See All Electroacoustics See All Noise Source Identification See All Environmental Noise See All Sound Power and Sound Pressure See All Noise Certification See All Industrial Process Control See All Structural Health Monitoring See All Electrical Devices Testing See All Electrical Systems Testing See All Grid Testing See All High-Voltage Testing See All Vibration Testing with Electrodynamic Shakers See All Structural Dynamics See All Machine Analysis and Diagnostics See All Calibration Services for Transducers See All Calibration Services for Handheld Instruments See All Calibration Services for Instruments & DAQ See All On-Site Calibration See All Resources See All Software License Management

The Egyptian Cubit: The Birth of Calibration

One of the earliest known units to measure length is the Egyptian cubit, which dates from the 3rd millennium BC.

Top image - Copyright © RMN-Grand Palais (musée du Louvre) / Hervé Lewandowski

What is a Cubit

A cubit is an ancient measurement of lenght. While the common cubit was the length of the forearm from the elbow to the tip of the middle finger – usually around 45.7 cm, the "royal cubit" was slightly longer: A common cubit plus the width of the palm of the Pharaoh ruling at the time.

The single royal cubit master (primary standard) was a rod carved from a block of black granite. Surviving cubit rods are between 52.2 and 52.9 cm in length. Workers were then supplied with copies – cubit sticks made of wood or granite. The royal architect or foreman of each construction site was responsible for maintaining the accuracy of these.


At every full moon, the cubit sticks had to be brought to the royal cubit master and compared to it. Failure to do so was punishable by death. With this standardization and uniformity of length, they achieved amazing accuracy.

As an example, the Great Pyramid of Giza is constructed with sides of 440 cubits (230.364 meters). Using cubit sticks, the builders were within 11.4 cm – an accuracy better than 0.05%.

Instrument Calibration
Royal cubit

The egyptian cubit shaped the first, basic ideas of modern calibration over 4000 years ago, and brought with it a common unit of measurement, traceability, a hierarchy of standards with regular re-calibration intervals.