I-Beam vs H-Beam: The Real Differences, With Numbers
I-Beam vs H-Beam: The Real Differences, With Numbers
"I-beam or H-beam?" is usually asked about a drawing that says one and a supplier that offers the other. The honest answer is that both are I-shaped sections, the difference is the flange — and the choice comes down to two numbers: how much depth you can afford, and whether the beam is loaded only in one direction.
What the letters mean (it depends on the continent)
- Europe: an I-beam is an IPE (parallel flanges) or IPN (tapered flanges) — flange width about half the depth. An H-beam is an HEA, HEB or HEM — flange width equal to the depth up to 300 mm, so the section looks like a capital H.
- United States: "I-beam" in the old sense is the S-shape (American Standard, tapered flanges, narrow), while the everyday structural beam is the W-shape — wide, parallel flanges, which most people also call an H-beam or wide-flange beam. HP-shapes are true H sections (depth = flange width) rolled for bearing piles.
So a European "H-beam" and an American "W-beam" are the same idea; a European "I-beam" and an American "S-beam" are the same idea. The rest of this article uses the European sections, because their tables are on this site and the numbers are exact.
Same height, three beams
Take the 200 mm size in each family, straight from our datasheets:
- IPE 200 — 200 × 100 mm, web 5.6, flange 8.5 mm · 22.4 kg/m · Ix 1,943 cm⁴ · Wx 194 cm³ · Iy 142 cm⁴
- HEA 200 — 190 × 200 mm, web 6.5, flange 10 mm · 42.3 kg/m · Ix 3,692 cm⁴ · Wx 389 cm³ · Iy 1,336 cm⁴
- HEB 200 — 200 × 200 mm, web 9, flange 15 mm · 61.3 kg/m · Ix 5,696 cm⁴ · Wx 570 cm³ · Iy 2,003 cm⁴
Three things jump out. The HEB carries almost three times the bending moment of the IPE (Wx 570 vs 194) at the same depth — but it weighs 2.7 times as much. Per kilogram of steel the strong-axis numbers are nearly identical: Wx/G is 8.7 cm³ per kg/m for the IPE, 9.2 for the HEA, 9.3 for the HEB. And the weak axis is where the families really part: Iy per kg/m is 6.3 cm⁴ for the IPE against 31.6 for the HEA and 32.7 for the HEB — five times stiffer sideways for the same weight.
Same weight, different depth
Now hold the weight and change the family. An IPE 300 weighs 42.2 kg/m — the same as the HEA 200:
- IPE 300: Ix 8,356 cm⁴, Wx 557 cm³, Iy 604 cm⁴, 300 mm deep
- HEA 200: Ix 3,692 cm⁴, Wx 389 cm³, Iy 1,336 cm⁴, 190 mm deep
For the same steel, the IPE is 2.3× stiffer and 43% stronger in bending — because its material sits 300 mm apart instead of 190. The HEA is 2.2× stiffer sideways and 110 mm shallower. That is the whole trade: the I-beam buys bending capacity with depth, the H-beam buys lateral stiffness and headroom with weight.
When the I-beam wins
- Simply supported floor and roof beams with the top flange held by a slab or decking, where the only real load is vertical bending. Depth is free, weight is what you pay for.
- Long spans on a budget. If a deflection check asks for Ix ≥ 8,000 cm⁴, an IPE 300 does it at 42 kg/m; the H-beam that matches it is an HEB 240 at 83 kg/m.
- Purlins, rafters, trailer and crane runway beams — same logic, one-directional loads.
When the H-beam wins
- Columns. A column buckles about its weak axis, and Iy is what stops it. An HEB 200 has 14× the weak-axis inertia of an IPE 200.
- Beams without lateral restraint — a beam whose top flange is free to move sideways fails by lateral-torsional buckling long before it reaches its bending capacity, and a wide flange resists that.
- Depth limits. Ceiling heights, road clearances, transfer beams in refurbishments: when every 10 mm counts, the shallow HEA or HEB carries the load the IPE would need 100 mm more to carry.
- Biaxial bending and crane brackets where loads come from two directions.
- Connections. A 200 mm flange takes two bolt rows and a wider bearing plate; a 100 mm flange often forces a stiffened detail.
The American pair
The same logic on the imperial side, at 8 inches: a W8x18 (wide flange, 5.25 in flanges, Ix 61.9 in⁴, Sx 15.2 in³, 18 lb/ft) against an S8x18.4 (American Standard, 4.0 in tapered flanges, Ix 57.6 in⁴, Sx 14.4 in³, 18.4 lb/ft). Same weight, same depth, the W is slightly stronger and its weak-axis inertia is more than double (7.97 vs 3.73 in⁴) — which is why S-shapes have all but disappeared from buildings and survive mainly as crane rails and in legacy structures.
Buying notes
- Stock and price. IPE and HEA/HEB are stocked everywhere in Europe in 6 and 12 m; W-shapes are the US default. Price per tonne is similar; the difference in your quote is the kilograms, so the I-beam is usually the cheaper beam and the H-beam the cheaper column.
- Do not substitute by name. "IPE 200" and "HEB 200" share nothing but the number. Substitute by Ix, Wx and — for anything unbraced or in compression — Iy.
- Check the deflection, not just the stress. For spans over about 5 m the L/250 or L/300 limit governs before the steel yields. Our beam deflection calculator opens any of these sections pre-filled from its datasheet.
Tables and tools
- Full tables with every size: IPE, HEA, HEB, W-shapes
- How to pick between IPE, HEA and HEB for a given job: IPE vs HEA vs HEB — how to choose
- What size beam a span needs: Steel beam span guide
- Weight of any length and quantity: Metal weight calculator