# Fastener Calc > Engineering calculators and converters for bolted joint design and assembly. (iPhone/iPad app by Bossard AG.) - Source: https://appshunter.io/ios/app/fastener-calc/id388420104 (this page in markdown: same URL + `.md`) - Developer: [Bossard AG](https://appshunter.io/developer/388420107) - Category: Productivity, Utilities - Price: $2.99 - Rating: 1.00/5 from 1 App Store ratings · 3 written reviews indexed - Age rating: 4+ - Requires: iOS 8.0 · 8 MB - Languages: American English - Released: 2010-10-13 - Data updated: 2026-06-05 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/fastener-calc/id388420104/reviews.md ## What is Fastener Calc? Bossard - Proven Productivity Bossard calculators and converters are designed for engineers, technicians, designers and students involved in the development and assembly of bolted joint. Calculators categories: * 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. --- Length converter is used for converting more than 68 different units of measure, such as inch, centimetre, metre, mile, foot, yard etc. --- Torque converter is used for converting different torques, such as newton metre, dyne metre, kilogram force metre, ounce force inch etc. --- Pressure converter is used for converting different pressure units, such as bar, millibar, psi, pascal etc. --- Force converter is used for converting different force units, such as newton, dyne, kilogram force, ounce force etc. --- Metric - imperial units fasteners converter. Converting between metric and inch fasteners forces you to make compromises.This converter gives you best proposals and will show you the differences in an easy way. --- Hardnes converter. Conversion of hardness-to-hardness or hardness-to-tensile-strength values for unalloyed and low-alloy steels and cast iron. * Geometrical calculators are used for dimensioning and implementation in the joining technology. --- Drill hole size for tapped threads. Calculate the proper tap drill size for the most commonly used screws. --- Pilot hole design for tapping screws. Calculate core hole diameters for tapping screws (Based on DIN 7975:1989) --- Pilot hole design for ecosyn®-Plast. Calculate the boss geometry for various types of thermoplastics for ecosyn®-plast. --- Tolerances for shafts and holes. Find and calculate tolerances for holes and shafts. Based on standard tolerance classes and limit deviations from ISO 286-2:2010 * Mechanical calculators are used for dimensioning and designing in the joining technology. --- Estimation of bolt size and property class. Which dimension and strength should a bolt have for my application? Estimate the required diameter and property class. Based on VDI 2230:2014. --- Disc spring calculator. Calculate disc springs with geometry and properties according to DIN 2093. Calculations based on DIN 2092. --- Cost savings calculator. Calculate savings potential for fasteners by looking at activity costs. --- Thread engagement length calculator. Calculate the theoretical minimum required thread engagement length for blind hole and through hole applications. Based on VDI 2230:2014 --- Torque and preload with nut factor. Calculate tightening torque and preload with nut factor for inch screws. Based on formula T = D*K*F. --- Torque and preload with nut factor and tool accuracy - imperial system. Calculate tightening torque and preload with nut factor for inch screws. The calculation considers tool accuracy and scatter on preload. --- Torque and preload with nut factor and tool accuracy - metric. Calculate tightening torque and preload with nut factor for metric screws. The calculation considers tool accuracy and scatter on preload. Based on formula T = D*K*Fmean --- Torque and preload with friction scatter. Calculate tightening torque and preload for hex head and socket head screws. The calculation considers friction scatter, tool accuracy and scatter on preload. Based on VDI 2230:2014 --- Torque and preload for customized geometry and material. Calculate tightening torque, preload and surface pressure for hex head, socket head and countersunk screws. Customized head shapes, hole chamfers, reduced shanks and materials are available options. Based on VDI 2230:2014 --- Torque and preload calculator. Calculate tightening torque, preload and surface pressure for hex head and socket head screws. Based on VDI 2230:2014. ## Key features - Unit converters (length, torque, pressure, force) - Metric-imperial fastener conversion - Drill hole size calculator - Tapping screw pilot hole design - Bolt size and property class estimation - Disc spring calculator - Thread engagement length calculator ## Recent user reviews (3 of 3) All indexed reviews: https://appshunter.io/ios/app/fastener-calc/id388420104/reviews.md ### 1/5 — Not worth the money *2011-12-13* No SAE values, waste of money. ### 1/5 — garbage *2011-02-17* very disappointed, metric only ### 3/5 — Okay app - but parts of it could be improved *2010-11-26* The app consists of three separate programs, a cost savings calculator, a torque and preload tool and a thread engagement calculator. Some (more) explanation/help file is needed for the cost savings calculator since its useage is not obvious (at least to me). The torque and preload calculator works well and is the best of the three calculators. The thread engagement calculator determines the thread stripping strength of the internal thread but not the bolt thread itself which can be the limiting factor when high strength steels are used. Also it does not allow you to enter your own material (i.e. the tensile strength and shear ratio) only to select from a list of materials, if yours is not on the list - tough. Considering the price this is good value but I look forward to an update addressing some of the above issues. ## Frequently asked questions about Fastener Calc ### What is Fastener Calc used for? Fastener Calc is used for dimensioning and designing bolted joints. It offers calculators for drill hole sizes, pilot holes, bolt estimation, and thread engagement length, along with various unit converters. ### What types of unit conversions does Fastener Calc offer? Fastener Calc includes converters for length (over 68 units), torque, pressure, force, metric-imperial fasteners, and hardness values for steel and cast iron. ### Does Fastener Calc support offline use? The provided data does not specify offline functionality. However, as a calculator and converter tool, it is likely designed to function without an active internet connection once installed. ### What devices is Fastener Calc available on? Fastener Calc is available on iPhone, iPad, and iPod devices, indicated by its supported devices list. ### How often is Fastener Calc updated? Fastener Calc was last updated on March 2, 2017, with version 2.2.1. This suggests a less frequent update cycle for the application. ### What is the age rating for Fastener Calc? Fastener Calc has an age rating of 4+, making it suitable for a wide range of users including younger students and professionals. ### What is the price of Fastener Calc? Fastener Calc is a paid application priced at $2.99. ### Does Fastener Calc have ads? Fastener Calc does not contain advertisements, as indicated by the 'hasAds' flag being false. ## Version history (last 5 releases) ### 2.2.1 — 2017-03-02 This app has been updated by Apple to display the Apple Watch app icon. Calculator logic fixes and small ui updates ### 2.2.0 — 2016-08-12 This update now also allows for use of the app in German: --- Small layout update to add side menu --- Hot swap languages, from any place in app --- Added disclaimer ### 2.1.0 — 2016-04-26 --- Layout update --- General stability fixes ### 2.0 — 2016-03-10 Welcome to a major update of our App! - We have completely redesigned our application. - Old calculators were updated to new standards. - We added 13 new calculators: --- Metric ↔ Inch Fasteners converter. Converting between metric and inch fasteners forces you to make compromises.This converter gives you best proposals and will show you the differences in an easy way. --- Hardnes converter. Conversion of hardness-to-hardness or hardness-to-tensile-strength values for unalloyed and low-alloy steels and cast iron. --- Drill hole size for tapped threads. Calculate the proper tap drill size for the most commonly used screws. --- Pilot hole design for tapping screws. Calculate core hole diameters for tapping screws (Based on DIN 7975:1989) --- Pilot hole design for ecosyn®-Plast. Calculate the boss geometry for various types of thermoplastics for ecosyn®-plast. --- Tolerances for shafts and holes. Find and calculate tolerances for holes and shafts. Based on standard tolerance classes and limit deviations from ISO 286-2:2010 --- Estimation of bolt size and property class. Which dimension and strength should a bolt have for my application? Estimate the required diameter and property class. Based on VDI 2230:2014. --- Disc spring calculator. Calculate disc springs with geometry and properties according to DIN 2093. Calculations based on DIN 2092. --- Torque and preload with nut factor. Calculate tightening torque and preload with nut factor for inch screws. Based on formula T = D*K*F. --- Torque and preload with nut factor and tool accuracy - Inch. Calculate tightening torque and preload with nut factor for inch screws. The calculation considers tool accuracy and scatter on preload. --- Torque and preload with nut factor and tool accuracy - Metric. Calculate tightening torque and preload with nut factor for metric screws. The calculation considers tool accuracy and scatter on preload. Based on formula T = D*K*Fmean --- Torque and preload with friction scatter. Calculate tightening torque and preload for hex head and socket head screws. The calculation considers friction scatter, tool accuracy and scatter on preload. Based on VDI 2230:2014 --- Torque and preload for customized geometry and material. Calculate tightening torque, preload and surface pressure for hex head, socket head and countersunk screws. Customized head shapes, hole chamfers, reduced shanks and materials are available options. Based on VDI 2230:2014 ### 1.3 — 2012-01-31 New module: Unit converter. Converts torque, pressure, force and length units. ## Apps similar to Fastener Calc | App | Rating | Price | Category | | --- | --- | --- | --- | | [eNet](https://appshunter.io/ios/app/enet/id1533792242) | — | Free | Productivity | | [care4bike](https://appshunter.io/ios/app/care4bike/id1617270994) | — | Free | Productivity | | [Digi-Pas Level Paid](https://appshunter.io/ios/app/digi-pas-level-paid/id1291143731) | — | $24.99 | Productivity | | [pocketREAD](https://appshunter.io/ios/app/pocketread/id658267345) | — | Free | Productivity | | [Wireless Balancer](https://appshunter.io/ios/app/wireless-balancer/id6747765790) | — | Free | Productivity | | [CTC EHS Near Miss Reporting](https://appshunter.io/ios/app/ctc-ehs-near-miss-reporting/id1229988010) | 1.0 (1) | Free | Productivity | ## More apps by Bossard AG - [ARIMS Mobile](https://appshunter.io/ios/app/arims-mobile/id1084843045) - [ARIMS Service App](https://appshunter.io/ios/app/arims-service-app/id6469774056) - [SFL SmartBin](https://appshunter.io/ios/app/sfl-smartbin/id6476139971) All apps by Bossard AG: https://appshunter.io/developer/388420107 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-05.*