Tons per Square Inch to PSI Converter

The Tons per Square Inch to PSI Converter converts pressure from long tons per square inch (tsi) to pounds per square inch (PSI). The conversion factor is 1 tsi = 2,240 PSI, since one long ton (imperial ton) equals 2,240 pounds. This unit is used in specialized heavy engineering and metallurgical contexts where extremely high pressures are involved.

The ton per square inch represents an enormous pressure — over 150 times atmospheric pressure. It has historical roots in British heavy engineering, particularly in the steel industry, shipbuilding, and the manufacture of heavy ordnance. Material hardness tests, rolling mill pressures, and the strength specifications of armor plate were traditionally expressed in tons per square inch in British engineering practice.

In metallurgy and materials testing, the Brinell hardness number was originally defined in terms of kgf/mm² but was sometimes reported as tsi in British publications. The ultimate tensile strength of structural steel (about 60,000–80,000 PSI) corresponds to approximately 27–36 tsi. High-strength alloys can exceed 100 tsi (224,000 PSI). These values help engineers evaluate materials for demanding applications like pressure vessels, bridge cables, and aerospace structures.

While this unit is largely historical, it still appears in legacy engineering references, British Admiralty specifications, and some industrial contexts in the UK and former Commonwealth countries. Converting tsi to PSI and MPa (the modern SI equivalent) allows engineers to use historical data with contemporary specifications. Our converter provides both PSI and MPa outputs for maximum flexibility.