Answer & explanation
The official answer, with Fermi’s reasoning step by step.
Answer & explanation
Official answer
1,500,000,000
bricks
How to estimate it
Fermi’s official “Napkin math”
Build it like a LEGO model, one layer at a time. The body covers about two basketball courts, call it 800 square meters, and about 2,000 bricks cover a square meter. How many layers to reach 10 meters? A brick is about a centimeter tall, so 1,000.
- Two basketball courts
- 800 m²
- Bricks per square meter
- × 2,000
- Layers (10 m ÷ 1 cm)
- × 1,000
- 1.6M a layer × 1,000
- ≈ 1.6 billion
Build it like a LEGO model, one layer at a time. The body covers about two basketball courts, call it 9,000 square feet, and about 200 bricks cover a square foot. How many layers to reach 30 feet? About 30 bricks stack to a foot, so 900.
- Two basketball courts
- 9,000 ft²
- Bricks per square foot
- × 200
- Layers (30 ft × 30)
- × 900
- 1.8M a layer × 900
- ≈ 1.6 billion
Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.
Source calculation & reference
- Great Sphinx: a 73 m × 19 m × 20 m box, about 27% of it solid stone (body, paws, head)
- ≈ 7,500 m³
- Space one 2x4 brick fills in a wall (32 × 16 × 9.6 mm)
- ≈ 4.9 cm³
- 7,500 m³ ÷ 4.9 cm³
- ≈ 1.5 billion
Reference cited by Fermi: Encyclopaedia Britannica (73 m long, 20 m high) · Wikipedia (19 m wide at the haunches) · LEGO's 8 mm stud, 9.6 mm brick grid
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