The working
- 1. Pitch multiplier√(1 + (4 ÷ 12)²)× 1.054
- 2. Roof anglearctan(4 ÷ 12)18.4°
- 3. Roof surface2,000 sq ft footprint × 1.054 (4/12 pitch multiplier)2,108 sq ft
- 4. Squares to order2,108 ÷ 100 = 21.1 squares, + 10% waste (gable roof)23.2 squares
- 5. Installed2,108 sq ft × $4–$6 per sq ft (architectural asphalt shingles, HomeGuide, Nov 7, 2025)$8,433 – $12,649
- 6. Tear-off2,108 sq ft × $1–$3 per sq ft to remove one layer (HomeGuide)$2,108 – $6,325
- 7. PermitFlat fee, set locally (HomeGuide, Fixr)$100 – $500
- 8. Installed totalSum, rounded to $100 under $10,000 and $500 above$10,500 – $19,500
Prices are published national installed ranges (mostly HomeGuide, updated Nov 7, 2025), the same ones the roof cost calculator uses, for a straightforward re-roof with one old layer torn off. They are not adjusted for your state; the calculator can do that. Decking repairs, access, steep or cut-up roofs and the contractor all move the final price, so get at least two written quotes.
Squares and the materials list come from the same math as the roof calculator, which works them out for your own measurements.
4/12 roof by footprint
| Footprint | Roof surface | Squares | Asphalt shingles | Standing-seam metal |
|---|---|---|---|---|
| 1,000 sq ft | 1,054 sq ft | 10.5 | $5,400 – $10,000 | $10,500 – $20,500 |
| 1,500 sq ft | 1,581 sq ft | 15.8 | $8,000 – $14,500 | $16,000 – $30,500 |
| 2,000 sq ft | 2,108 sq ft | 21.1 | $10,500 – $19,500 | $21,000 – $40,500 |
| 2,500 sq ft | 2,635 sq ft | 26.4 | $13,500 – $24,000 | $26,500 – $50,500 |
| 3,000 sq ft | 3,162 sq ft | 31.6 | $16,000 – $29,000 | $31,500 – $60,500 |
Compared with nearby pitches (2,000 sq ft footprint)
| Pitch | Angle | Area multiplier | Walking it | Asphalt shingles |
|---|---|---|---|---|
| 2/12 | 9.5° | × 1.014 | Low slope | $10,000 – $18,500 |
| 3/12 | 14.0° | × 1.031 | Low slope | $10,500 – $19,000 |
| 4/12 | 18.4° | × 1.054 | Low slope | $10,500 – $19,500 |
| 5/12 | 22.6° | × 1.083 | Walkable with care | $11,000 – $20,000 |
| 6/12 | 26.6° | × 1.118 | Walkable with care | $11,500 – $20,500 |
Did hail hit your area? Insurance often covers hail damage. Check hail history for your city, with storm reports back to 1955.
Questions people ask
What is the multiplier for a 4/12 roof?
1.054. Multiply the footprint by it to get the sloped roof area: 2,000 sq ft of footprint is 2,108 sq ft of roof.
What angle is a 4/12 pitch?
18.4 degrees. It rises 4 inches for every 12 inches across.
Is a 4/12 roof walkable?
Low slope: generally walkable in dry conditions. OSHA classes roofs up to 4/12 as low-slope.
More roof cost guides
- Flat roof cost and squares
- 3/12 pitch roof: multiplier, angle and cost
- 5/12 pitch roof: multiplier, angle and cost
- 6/12 pitch roof: multiplier, angle and cost
- 7/12 pitch roof: multiplier, angle and cost
- 8/12 pitch roof: multiplier, angle and cost
- 9/12 pitch roof: multiplier, angle and cost
- 10/12 pitch roof: multiplier, angle and cost
- 12/12 pitch roof: multiplier, angle and cost
- Roof cost for a 1,000 sq ft house
- Roof cost for a 1,200 sq ft house
- Roof cost for a 1,500 sq ft house
- Roof cost for a 1,800 sq ft house