Steel has a high strength-to-weight ratio, meaning less steel is required in a beam than if other materials used, which makes it a sustainable and cost-effective choice. Steel is capable of withstanding high loads with minimum deflection, which prevents movement and cracking of brittle finishes such as masonry and plaster. Steel I-beams are often used in modern construction, because they are smaller and less wasteful than their wooden counterparts. Making sure that you use the right size of steel beam for your project is essential, and there are different factors that need to be considered when calculating beam size.

Steel beam size table

Below there is a table of commonly used steel beam sizes in the UK on small projects:

Dimensions Depth (mm) Width (mm) Weight per metre (kg/m)
152x89x16 UB 152.4 88.7 16
178x102x19 UB 177.8 101.2 19
152x152x23 UC 152.4 152.9 23
152x152x30 UC 157.6 152.9 30
203x102x23 UB 203.2 101.8 23.1
203x133x25 UB 203.2 133.2 25.1
203x133x30 UB 206.8 133.9 30
203x203x46 UC 203.2 203.6 46.1
203x203x52 UC 206.2 204.3 52
254x146x31 UB 251.4 146.1 31.1
254x146x37 UB 256 146.4 37
254x146x43 UB 259.6 147.3 43

The benefit of steel beams is that they are manufactured to exact sizes, shapes and strengths. There are of course dozens of steel beam sizes available. So, this table is just to be used as a guide on small projects. These sizes are stocked by most steel fabricators.