The Asphalt Shingle Roof Cost Calculator prices a shingle roof the way a roofer's quote is built: the shingles installed per square, tear-off of the old layer as its own line, and any permit or fixed costs you already know. Enter the sloped roof area, or the house footprint and pitch, choose 3-tab or architectural shingles, and it returns the installed range, the number of bundles to order with waste, the cost per square foot and per square, and the cost per year of service. Architectural shingles typically install for $450 to $650 per square and 3-tab for $390 to $480, with one tear-off layer adding $100 to $175 per square. Because architectural shingles last longer, they usually cost less per year even though they cost more on the day, which is why the calculator reports both.
An asphalt shingle roof is priced per square — 100 square feet of sloped roof — installed, with the tear-off of the old layer priced as its own line. Architectural shingles typically install for $450 to $650 per square and 3-tab for $390 to $480; removing one existing layer adds about $100 to $175 per square.
| Roof area | Squares | 3-tab installed | Architectural installed | Bundles at 10% waste |
|---|---|---|---|---|
| 1,000 sq ft | 10 | $3,900 – $4,800 | $4,500 – $6,500 | 33 |
| 1,500 sq ft | 15 | $5,850 – $7,200 | $6,750 – $9,750 | 50 |
| 2,000 sq ft | 20 | $7,800 – $9,600 | $9,000 – $13,000 | 66 |
| 2,500 sq ft | 25 | $9,750 – $12,000 | $11,250 – $16,250 | 83 |
| 3,000 sq ft | 30 | $11,700 – $14,400 | $13,500 – $19,500 | 100 |
3-tab shingles are commonly rated for 15–20 years and architectural for 25–30. On a 2,000 sq ft roof that is roughly $497 a year for 3-tab against $400 for architectural — the more expensive shingle is usually the cheaper roof.
Installed, architectural shingles run about $4.50–$6.50 per sq ft ($450–$650 per square) and 3-tab about $3.90–$4.80 ($390–$480 per square). Tearing off one old layer adds roughly $1.00–$1.75 per sq ft.
About $9,000–$13,000 for architectural shingles installed, or $7,800–$9,600 for 3-tab, before tear-off. Add $2,000–$3,500 to remove one existing layer, plus any permit and deck repairs.
3-tab costs less to install but is commonly rated for 15–20 years against 25–30 for architectural. Divide the price by the years of service and architectural usually comes out cheaper per year — the calculator shows both figures.
Code generally allows a second layer over one sound layer, which saves the tear-off. Most roofers still recommend stripping it: you can see and fix the deck, and some shingle warranties are reduced over an existing layer.
Most of the spread is scope: which shingle line, synthetic or felt underlayment, how much ice and water shield, new flashing and drip edge, and how many deck sheets are allowed for. Ask every roofer to itemise those and compare line by line.