Weight estimator

• Beam, column or channel: the weight per metre from British Steel's section tables (BS EN 10365) times the length.
• Angle: the thickness times the two legs added together, less the thickness, times the length. The rounded root and toes are left out.
• Hollow section: a square or rectangular hot-finished section with corner radii of 1.5 and 1.0 times the wall, as BS EN 10210-2 sets out.
• Plate, block or slab, round bar or pile, and pipe, tube or ring: length times width times thickness, or the area of the circle or ring times the length.
• Round tank or vessel: the shell as a pipe, plus two ends at the same thickness. A flat end is a disc. A dished end is taken as the common 2:1 shape, a quarter of the diameter deep, with a surface of 1.084 times the diameter squared.
• Box tank: the outside box less the inside box, with an open or closed top.

Each material starts with a density you can change:

• Steel 7,850 kg/m³, the figure the Blue Book section tables use
• Stainless steel 7,900 kg/m³ (BS EN 10088-1, grade 1.4301) and aluminium 2,700 kg/m³ (BS EN 1999-1-1)
• Cast iron 7,250, copper 8,900, brass 8,500 and lead 11,400 kg/m³, from the unit weights in BS EN 1991-1-1 Annex A
• Concrete 2,400 kg/m³ plain and 2,500 kg/m³ reinforced, also from BS EN 1991-1-1 Annex A
• Softwood 420 and hardwood 700 kg/m³, the mean densities of C24 and D40 timber in BS EN 338, dry

The Eurocode gives unit weights in kN/m³. They are turned into kg/m³ at 10 kN to the tonne, as the Blue Book does. Wet timber and heavily reinforced concrete weigh more than these figures.

The contents fill the inside of the tank: the outside sizes less the wall. Water is 1,000 kg/m³, seawater 1,025, diesel and gas oil 845 (the top of the range in BS EN 590) and hydraulic oil 880. For anything else, choose Other and enter its density. The fill is a share of the inside volume, so a lying tank half full holds half its volume whatever the depth.

The margin covers what the sizes don't show. It starts at 5% for steel and other metal shapes and 10% for concrete. Tanks and vessels start at 15%, as they carry nozzles, manways, ladders and supports. These are our planning figures, not a published rule, and you can change them. The contents of a tank get no margin, as their weight comes straight from the volume and the fill.

Fittings, bolts and welds, paint, galvanising and insulation, anything left in a tank you have entered as empty, and the small difference that rolling tolerances allow on steel sections. The slings, shackles, beams and hook block are part of the load on the crane too, as HSE's L113 explains. Use the maker's weight or a weighing where there is one, and our guide to steel beam weights for how a section's weight is read from its size.