Bolt Length Calculator for HV Bolts (EN 14399-4)

Andrews Fasteners Bolt Length Calculator for BS EN 14399 High-strength structural bolting assemblies for preloading (System HV)

HV Bolt to EN 14399-4:2015

This calculator is for guidance only. It calculates the minimum recommended bolt length considering the maximum allowed thickness of the assembly components and steelwork.

This information is provided in good faith and is for your guidance only. Andrews Fasteners Limited cannot accept any liability for actions taken by third parties based on this information.

HV Bolt Length Calculator

Steelwork thickness mm
Bolt length (calculated):
Bolt length (ref.):
Version: JS/1.00.030524.14399.2015

While the information is provided in good faith, Andrews Fasteners Ltd accepts no responsibility or liability for errors or inaccuracies in the information, or for any reliance placed on it by the user.

Nut used in calculation refer to EN 14399-4 (HV Nut)

Washer refer to EN 14399-5 (4) (washer under the nut) or EN 14399-6 (4) (chamfered washer under bolt head) - Hardness 300-370 HV

NFW (2) refers to Nut Face Washer EN 14399-9 (Hard washer) - Hardness 38-45 HRC

BFW (2) refers to Bolt Face Washer EN 14399-9 (Hard washer) - Hardness 38-45 HRC

DTI (1) refers to Direct Tension Indicators Washer EN 14399-9 - Hardness max. 380 HV - maximum height including protrusions (3).

Steelwork thickness refers to the combined thickness of steel elements being bolted together. It’s important to include a minimum of 1 thread protruding beyond the face of the unloaded nut on the assembly. If additional plates are needed, such as for oversized holes, their thickness should be added to the total steelwork thickness.

For calculation of thread lengths refer to:

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