As a welder, it’s important to be able to read welding symbols and blueprints, as this is an important way that drafters and architects communicate their wishes to you. However, the vast majority of welders struggle to read welding symbols and blueprints since it requires a lot of memorization and practice, and if you just don’t have the need to use these symbols frequently, it can seem superfluous.

However, the Missouri Welding Institute deems that as a new welding student having just completed your welding certification program, it is vital that you can read welding blueprints. Not only will this help to differentiate you from other welding candidates — even welding candidates with experience — but it can also help land you a job where reading welding blueprints is required. There is a lot to welding symbols. However, below, we’ll take a look at some basic steps to reading and interpreting them. Contact us today for your free information packet!


The horizontal line is the reference line where all of the other welding symbols are tied to. All of the instructions for making the weld are on this reference line. An arrow will connect the reference line to the joint that is to be welded. All weld symbols contain at least one arrow and one reference line.

Frequently, there are two sides to the joint where a weld can take place. The arrow helps to distinguish between the two sides by using the arrow and the space above and beyond the reference line. A flag indicates if a weld is to be made in the shop or outside of the shop, and an open circle indicates if the weld is to go all around the joint or not.

Every type of weld has its own symbol, as well as the overall welding job, which can be confusing. Placement of the weld symbol is key as well, as there are different meanings and interpretations, depending on where you want the weld to be executed. For example, if the weld symbol is placed above the reference line, the weld should be made on the opposite side of the joint. If the weld symbol is placed underneath the reference line, the weld should be performed on the arrow side of the joint.

Dimensions and Angles

Dimensions and angles are a big component of making welding parts that fit with existing materials. Width or diameter in welding blueprints are written on the left of the weld symbol. It is usually always written in a fraction and in inches. If by chance the size of the weld appears above the reference line, then this applies to the joint opposite of where the arrow is. If the weld symbol appears below the reference line, then the instructions apply to the side of the joint where the arrow points.

Angles, openings, and dimensions are included in the welding symbol itself. Some welding symbols will also indicate if the weld should mirror each other or be offset.

Other common welding instructions will appear on optional tails on the side opposite the arrow. This is often written words that explain details outside of the normal parameters for a typical weld. This is frequently employed for odd-sizes or odd-angled welds. Other instructions that can be included is the method of welding, such as using stick welding.


  • Don’t rush reading the blueprints. Make sure you understand all of the instructions, rather than make a mistake that ends up costing money and time in the long run.
  • Quiz yourself. Periodically review the blueprint symbols, and see how many you can remember.
  • Practice. The more you practice reading welding blueprints, the easier it will be. You can practice visualizing in your mind how to execute what the welding blueprints are telling you as well.


Missouri Welding Institute understands that there is a lot to welding symbols and reading welding blueprints. It’s easy to mix them up as well, misinterpret them, and then execute the weld incorrectly. This leads to an unhappy customer and wasted time, effort, and money in materials and supplies as you now have to redo your work.

Cheat sheets with your most frequently used symbols or of welding symbols that you have a hard time remembering what they mean are a good idea to make and keep handy when reading your welding blueprints sent over by your client. By making the effort to learn to read welding blueprints, you’ll make yourself more valuable as a welder. Your skill will grow, your welds will be better, and you’ll be a highly successful welder in no time. Contact Missouri Welding Institute today for enrollment information!