Free Truss Calculator / Roof Rafter Calculator

Calculate the Axial forces for Truss, Roof and Rafters

About this Truss Calculator

This free online truss calculator is a truss design tool that generates the axial forces, reactions of completely customisable 2D truss structures or rafters. It has a wide range of applications including being used as a wood truss calculator, roof truss calculator, roof rafter calculator, scissor truss calculator or roof framing. Trusses are typically modelled in triangular shapes built up of diagonal members, verical members and horizontal members.

How to use this Rafter Calculator?

Simply add nodes, members and supports to set up your model, apply up to 5-point loads (distributed loads can be added in full version), then click solve to run the static 2D truss analysis. It is particularly useful as a steel bridge truss design software or roof truss calculator. Click 'Reactions' or 'Axial Force' to display your results in a nice, clean and easy-to-interpret graph for your truss design. Users can also control settings such as units, display settings of truss members etc. by clicking the 'Settings' button.

This rafter truss calculator, has a range of applications including being used as a wood truss calculator, roof truss calculator, roof rafter calculator, scissor truss calculator or for roof framing. By upgrading to on of SkyCiv's pricing options, you'll have access to full structural analysis software so you select materials such as wood and steel to perform truss designs - making it much more than a simple roof calculator.

Need More Functionality?

Upgrade to a professional plan to unlock full features

Hand Calculations

SkyCiv shows the step by step calculations for how to calculate a truss and the axial forces using method of joints. Upgrade to a paid plan to view these interactive hand calculations.

Unlimited Loads & Supports

Add as many supports, loads, and members with on of SkyCiv paid plans. Tackle any truss designs with this powerful and fast truss software.

Truss Design Software

Run design checks on your trusses as per AISC, NDS, Australian Standards, CSA and Eurocode. Simply model your truss structure and run beam design checks as you need them.

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Rafter Calculator

Whether you call them rafters, truss members or beams - the truss calculator essentially does the same thing. It calculates the internal axial forces in these members. The internal forces are important as they are commonly the governing force to look for in truss structures. Such structures are frequently used in long span structures such as truss bridge design and roof trusses.

Truss Solver

The truss analysis is being performed by our FEA solver, which is also used in our Structural 3D program. The calculations made are based on splitting the member into 10 smaller elements and calculating the internal forces based on these. The Truss solver can handle extremely large structures of more than 10,000 members. So if you have a larger structure, simply upgrade and you can use the full S3D program for all your analysis needs.

More Information on Trusses

A truss is typically a triangular structure that is connected by pinned joints such that they mainly incur an axial force (see what is a truss). This above tool will allow you to run truss analysis on any of these trusses to get the internal member forces. There are a number of different types of trusses, including pratt truss, warren truss and howe truss; each with their own set of pros and cons.

Do More With Structural 3D

There are some limitations on the above truss calculator that can be achieved through full structural analysis software. Get more results (such as bending moment and shear force diagrams), get more members and loading types (area loads, distributed loads and self weight) and model in 3D.

About SkyCiv

SkyCiv offers a wide range of Cloud Structural Analysis and Design Software for engineers. As a constantly evolving tech company, we're committed to innovating and challenging existing workflows to save engineers time in their work processes and designs.



If you are an engineering professional, you might benefit more by using our cloud based 3D Structural Analysis Software beyond this calculator. This software includes integrated design modules such as AISC, ACI, AS, Eurocode and CSA. Check out our professional packages here:

3D Structural Analysis Software


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