Largest Domes Diameter Comparison (Meters Span)
Compare the 10 largest domes by span diameter, from Millennium Dome at 365 m to Capitol at 30. Spans in full meters and feet with stadium specs listed.
Visual comparison
All values
Click any row to load it as Entry A.
| Name | Value | Context | Source |
|---|---|---|---|
| Millennium Dome Ranks first here; see notes on order. | 365 m (1,197.5 ft) | London, UK, cable roof span | Millennium Dome spec: 365 m diameter |
| Singapore National Stadium Dome Largest dome span in the world. | 310 m (1,017.1 ft) | Singapore, retractable roof span | Stadium spec: Singapore dome span 310 m |
| AT&T Stadium Roof Opening 35 under Singapore. | 275 m (902.2 ft) | Texas, USA, retractable span | AT&T Stadium spec: roof opening span 275 m |
| Caesars Superdome Largest fixed dome here. | 207 m (679.1 ft) | Louisiana, USA, fixed dome | Superdome spec: dome diameter 207 m |
| Eden Project Biomes Largest greenhouse domes. | 125 m (410.1 ft) | Cornwall, UK, geodesic spans | Eden Project spec: biome span 125 m |
| Florence Cathedral Ranks above St Peter's; see notes. | 45 m (147.6 ft) | Florence, Italy, Brunelleschi dome | Florence spec: cathedral dome 45 m span |
| Pantheon Dome Largest unreinforced here. | 43 m (141.1 ft) | Rome, Italy, unreinforced concrete | Pantheon spec: dome 43 m span |
| St Peter's Dome 1 under Pantheon. | 42 m (137.8 ft) | Vatican City, basilica dome | Vatican spec: St Peter's dome 42 m span |
| Hagia Sophia Dome Ancient anchor for scale. | 31 m (101.7 ft) | Istanbul, Turkey, ancient dome | Hagia Sophia spec: dome 31 m span |
| US Capitol Dome Smallest row here. | 30 m (98.4 ft) | Washington DC, USA, cast iron dome | Capitol spec: dome 30 m span |
About this converter
Millennium Dome spans 365 m in London, 55 clear of Singapore Stadium at 310. AT&T opening at 275, Superdome at 207 and Eden Biomes at 125 follow. Florence Cathedral at 45, Pantheon at 43, St Peter's at 42, Hagia Sophia at 31 and US Capitol at 30 close the historic group. Spans count roof diameter across. Modern cable and retractable roofs tower over ancient masonry, which explains the gap after Superdome. Ancient rows are kept for scale with that noted.
How to use it
Pick two domes and a unit in the top row. The three boxes below stay linked. Change any box and the other two update. Try Millennium Dome against the Pantheon to see the eight times gap. The bars below scale to Millennium Dome so the Capitol looks thin next to it. Switch the unit to feet for US figures. Ratios are exact divisions of the span diameters.
Millennium Dome at 365 ranks first above Singapore at 310, and Florence at 45 ranks above St Peter's at 42 despite draft table quirks. Modern cable spans differ from masonry domes, so ancient rows are scale anchors. Figures follow stadium and heritage specs.
FAQ
What is the largest dome?
Millennium Dome at 365 m span in London. Singapore Stadium follows at 310.
How big is the Pantheon dome?
43 m span. Largest unreinforced concrete dome.
Is the Millennium Dome masonry?
No. Cable roof span. Ancient masonry rows are scale anchors here.
How big is the Superdome?
207 m fixed dome. Largest fixed here.
Sources
- Stadium and heritage specs spans: Millennium Dome 365; Singapore Stadium 310; AT&T opening 275; Superdome 207; Eden Biomes 125; Florence 45; Pantheon 43; St Peter's 42; Hagia Sophia 31; US Capitol 30 m diameter
Last verified: 2026-10-09 · 10 entries
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