Mettler Toledo, stylized in all caps, is a multinational supplier of precision instruments and services. The company focuses on laboratory, industrial, product inspection, and food retailing applications. Its products are used in research, quality control, and manufacturing processes in life sciences, food, chemical, and many other industries. The company's business is geographically diversified, with sales in 2023 derived 41% from North and South America, 27% from Europe, and 32% from Asia and other countries. The company’s global workforce consists of 17,300 employees as of December 31, 2023.

Allen DeVilbiss, Jr. (1873-1911) was an inventor who lived in Toledo, Ohio, United States. He became interested in the concept of weighing machines, and conceived the idea of an automatic computing pendulum scale. He was able to prove his concept with a local butcher, who realized that customers appreciated the automatic computation which eliminated the risk of overcharging. While his invention gained in popularity, DeVilbiss was not interested in making it a viable business.^{[self-published source]}

In 1900, Henry Theobald (1868-1924) was fired from his job at the National Cash Register Company. He decided to start his own business, and was convinced that selling the automatic computing scales could be a good venture. He solicited additional financial investors and purchased the company from DeVilbiss. On July 10, 1901, the Toledo Computing Scale and Cash Register Company was incorporated.

By May 1902, Theobald's company was selling more than 100 cash registers with scales per month. By that time, John H. Patterson, Theobald's boss from NCR, threatened to sue the new company for patent infringements. As an alternative, Patterson offered to purchase all cash register patents and property, along with the stipulation that Theobald would no longer engage in the cash register business. The investors, who worried about the costs of patent infringement litigation, agreed to the sale in June 1902. Since cash registers were no longer part of Theobald's business, he changed the name to Toledo Computing Scale Company. Theobald later coined the phrase "No Springs, Honest Weight" as a slogan for the new company.

In the years that followed, Theobald realized that the weighing scale was the most important part of the retail transaction between the merchant and the customer. He felt that many of his competitors who used spring scale technology, especially Dayton Scale Company, were allowing merchants to cheat their customers by incorrectly calculating the total price of a measured good. He campaigned for more government regulation of weights and measures to eliminate dishonest weighing systems. On October 1, 1907, Massachusetts adopted the first weights and measures laws in the United States.

In 1912, the company name changed once again, to Toledo Scale Company. Additionally, a new scale line featuring a double pendulum mechanism and a dial face was introduced and was most suited for industrial applications.

In 1957, Reliance Electric Co, merged with Toledo Scale Co. Reliance paid about $70 million in stock for the purchase.

In 1945, Dr. Erhard Mettler Rook, a Swiss engineer, started a precision mechanics company in Küsnacht, Switzerland. He invented the substitution principle with a single-pan balance, capable of being produced in series. Analytical balances with a single weighing pan gradually replaced conventional two-pan balances in the laboratory.