Ultimate master cheat sheet for the entire CN Tower project, consolidating all the measurements, blueprints, and internal floor spacings we’ve discussed into one complete list.
Every single measurement here is calculated specifically for HO Scale (1:87) and converted directly to millimeters (mm).
1. Overall Specifications
These are your primary external dimensions for the major structural milestones.
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Total Final Constructed Height: 6,360 mm
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Top of Concrete Support Arms: 3,793 mm
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SkyPod (Highest Observation Deck): 5,138 mm
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Maximum Width of Main Pod: 454 mm (Diameter)
2. Base & Foundation Levels
Note: In the architectural blueprints, the Lobby floor is treated as Ground Zero (0 mm).
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Deck Level: +46 mm
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Lobby Level: 0 mm (Ground level)
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Pool Level: -28 mm (Below ground)
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Service Level: -74 mm (Below ground)
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Bottom of Concrete Foundation: -172 mm (Lowest excavated point)
3. The Main Pod (Elevations & Floors)
This section outlines exactly how high each specific floor sits above the lobby level, as well as the internal gap between each floor.
| Pod Level | Elevation (Height Above Lobby) | Internal Floor-to-Floor Gap |
| Roof | 4,106 mm | – |
| Level 7 (Mechanical) | 4,050 mm | 56 mm (Up to Roof) |
| Level 6 (Transmission FM) | 4,004 mm | 46 mm (Up to Lvl 7) |
| Level 5 (Transmission UHF) | 3,952 mm | 53 mm (Up to Lvl 6) |
| Level 4 (Restaurant) | 3,910 mm | 42 mm (Up to Lvl 5) |
| Level 3 (Indoor Obs.) | 3,857 mm | 53 mm (Up to Lvl 4) |
| Level 2 (Outdoor Obs.) | 3,808 mm | 49 mm (Up to Lvl 3) |
| Level 1 (Microwave/Radome) | 3,759 mm | 49 mm (Up to Lvl 2) |
4. Upper Mast & Antenna
These are the elevations for the specific broadcasting rings and platforms above the main pod, measured from the Lobby level up.
| Mast Feature | Elevation (Height Above Lobby) |
| Final Constructed Peak | 6,360 mm |
| Top of Blueprint Antenna | 6,236 mm |
| Channel 79 | 6,166 mm |
| Channel 45, 51, 57 | 5,991 mm |
| Channel 19, 25 | 5,763 mm |
| Channel 9 | 5,570 mm |
| Channel 5 | 5,343 mm |
| FM Broadcasters | 5,133 mm |
| Upper Platform (Base of Mast) | 5,052 mm |
The CN Tower’s width tapers drastically from a massive sprawling base to a tiny needle at the top. Here are the key horizontal measurements (widths, diameters, and footprints) you will need, converted into your 1:87 HO scale in millimeters.
Horizontal Dimensions (Widths & Diameters)
| Structural Element | Real-World Measurement | HO Scale (1:87) in Millimeters |
| Maximum Base Footprint (Tip-to-tip of the Y-shaped legs) | ~66.6 m (218 ft) | 765.5 mm |
| Width of Individual Concrete Legs (At ground level) | ~7.0 m (23 ft) | 80.5 mm |
| Central Hexagonal Core Shaft (Average width above the legs) | ~10.0 m (33 ft) | 115.0 mm |
| Main Pod Maximum Diameter (Widest point at Level 3 & 4) | 39.5 m (130 ft) | 454.0 mm |
| Main Pod Lower Radome (Narrower bottom of the main pod) | ~25.0 m (82 ft) | 287.3 mm |
| SkyPod Diameter (The smaller upper observation deck) | ~10.0 m (33 ft) | 115.0 mm |
| Antenna Tip Diameter (At the very peak) | 1.5 m (5 ft) | 17.2 mm |
Model-Maker’s Takeaways for the Widths:
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The Base Footprint: At 765.5 mm (about 30 inches) across the base legs, your model is going to need a very solid, wide display table. That wide stance is exactly what keeps the real 1,815-foot tower from tipping over in the wind, and it will do the same for your 20-foot model.
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The Core Shaft: The main hexagonal concrete pillar that shoots up the center is actually quite slender relative to its height. In your model, this core will be roughly 11.5 cm (4.5 inches) thick for the majority of the climb.
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The Main Pod: As we calculated earlier, the absolute widest point of your build will be the belly of the Main Pod at 45.4 cm (almost 18 inches) across. It will cantilever dramatically off that relatively narrow 11.5 cm central core!
The real-world widths of the antenna mast and how they translate into millimeters for your 1:87 HO scale model:
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Base of the Antenna Mast: Where the steel mast bolts into the concrete at the Upper Platform, it is 12 feet (3.66 meters) wide.
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HO Scale: 42.0 mm * The Fiberglass Radome: As shown in your vintage clipping, the upper transmission antennas are wrapped in a protective fiberglass radome that bulks the diameter out to 5 feet (1.52 meters) wide.
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HO Scale: 17.5 mm * Top of the Bare Steel Mast: The bare metal at the very peak (the lightning rod section) slims down to just 2 feet (0.61 meters) wide.
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HO Scale: 7.0 mm Model-Maker’s Tip: To build the 1.17-meter tall antenna for your model, you could use a tapered wooden dowel or a piece of styrene tubing. You would want it to start at about 42 mm (1.65 inches) thick at the bottom and shave it down to a 7 mm (0.28 inches) point at the tip, wrapping a slightly thicker 17.5 mm (0.68 inches) sleeve near the top to represent the radome covering.
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