Bossard calculators and converters are designed for engineers, technicians, designers and students involved in the development and assembly of bolted joint.

Online converters

The Bossard «Online converters» are used for converting different units of measure, such as lengths, hardnesses, pressures etc. The converters are divided into topic areas to enable the most efficient selection possible.


Online calculators for design / production

The Bossard calculators for design / production are used for dimensioning and implementation in the joining technology.


Online calculators for technical design

Bossard calculators for design are used for dimensioning and designing in the joining technology.

Apps for mobile devices

Bossard Online calculators and converters are available as practical app. You remain mobile at all times. For further information, visit the App Store.

Fastener Calculator App for iOS and Android

App Store 
iOS App Store

Download from Google play 
Google Play Store


This app contains the following tools:

  • Converters: Length Converter, Torque Converter, Pressure Converter, Force Converter, Metric-imperial Units Fasteners Converter, Hardness Conversion
  • Geometrical Calculators: Drill Hole Size for Tapped Threads, Pilot Hole design for Tapping Screws, Pilot Hole Design for Ecosyn®-plast Screws, Tolerances for Shafts and Holes
  • Mechanical Calculators: Estimation of Bolt Size and Property Class, Disc Spring Calculator, Cost Savings Calculator, Thread Engagement Length Calculator, Torque and Preload with nut factor (imperial system), Torque and Preload with Nut Factor and Tool Accuracy (imperial system), Torque and Preload with Nut Factor and Tool Accuracy (metric), Torque and Preload with Friction Scatter, Torque and Preload for Customized Geometry and Material, Torque and Preload Calculator



The engineering calculators are free to use under the terms and conditions set out under Imprint. The calculators shall facilitate and support you when designing products. The results depend on assumptions you provide. We do not guarantee their accuracy or applicability to your circumstances. For a thorough engineering advice please contact us.

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