Roof Replacement Cost Calculator

How to use the roof replacement cost calculator

1. Size the roof. If you know the footprint, the area covered by the roof seen from above, enter it with the pitch. For a one-story house the footprint is close to the floor area plus any attached garage and porch roofs. Already have a roofer’s measurement report or a satellite report? Switch to Roof area and type the total.
2. Pick the new material. The price per square foot shown beside each option is the installed price, materials and labor together.
3. Tell it what comes off. A replacement price normally includes tearing off one layer. If the house has two or three layers of shingles, enter the extra layers and whether the old roof is light (shingles, metal) or heavy (tile, slate).
4. Add what your roofer flagged. Soft decking found at tear-off, new drip edge, gutters, skylights, vents, a full flashing replacement and the permit are separate lines.

The breakdown lists every line so you can hold it up against a written bid. The price per square at the bottom is the figure most roofers quote, so it is the quickest number to compare.

Why pitch changes the roof area, and the bill

Roofing is sold and installed by the square, 100 square feet of roof surface. A sloped roof has more surface than the ground it covers, and the difference grows with pitch. The calculator multiplies the footprint by the slope factor, the square root of 1 + (rise ÷ 12)². At 4/12 that factor is 1.054, at 6/12 it is 1.118, at 8/12 it is 1.202 and at 12/12 it is 1.414.

That is the same conversion HomeGuide uses in its cost table: a 2,000 sq ft single-story house at 6:12 is listed with a 2,235 sq ft roof, and a 1,000 sq ft house with a 1,120 sq ft roof. Enter 2,000 and 6/12 here and you get 2,236 sq ft, about 22.4 squares. Two-story houses have a smaller footprint than their floor area, so use the footprint, not the living space.

Pitch costs money twice: it adds area, and HomeGuide notes that roofs steeper than 6:12 take extra safety precautions and labor, and Angi puts an unusually steep pitch at $1,000 to $3,000 extra. Switch on the steep-roof line if your roof is one you would not walk on. For pitch conversions and rafter lengths, use the roof pitch calculator.

Roof replacement cost by material

These are HomeGuide’s installed ranges. On its numbers, a typical asphalt reroof runs $5,700 to $16,000, and the low and high ends of its house-size table are exactly the roof area times $3 and $6 per square foot. Angi, working from 2026 project data, reports a $9,610 national average and a typical range of $5,903 to $13,378, or $4 to $11 per square foot across materials. The two guides agree well for shingles. The spread widens for metal and tile because product choice matters so much: corrugated panels and copper standing seam are both “metal roofs.”

Heavier roofing can need more than a bigger budget line. HomeGuide warns that slate may need structural reinforcement, and switching from shingles to tile can mean added trusses. If you are changing to a much heavier material, ask whether the framing has been checked.

Tear-off, decking and the other lines that surprise people

• Extra layers. Removing roofing costs $1 to $3 per square foot for shingles or metal and $2 to $5 for slate or tile (HomeGuide), and it depends on how many layers there are. The calculator assumes your installed price covers one layer and charges that rate for each extra one. Most cities allow no more than two layers in total, so a roof-over on a roof that already has two is usually off the table.
• Decking. Nobody knows how much sheathing is rotten until the old roof is off. HomeGuide prices replacement at $2 to $5 per square foot. Ask your roofer for a per-sheet price in the contract and use the decking percentage here to see what 10% or 20% would add.
• Edges and water. Drip edge runs $1.50 to $3 per linear foot, and replacing gutters $12 to $25 per foot. New gutters are not required with a new roof, but it is cheaper to do both while the crew and dumpster are already there.
• Penetrations. Skylight replacement is $800 to $2,400 each, a new roof vent $200 to $700, and a full flashing replacement $400 to $1,000. Many bids include standard vents and flashing; the switches are for when yours does not.
• Permits. HomeGuide gives $100 to $500; Angi’s range runs up to $1,400 depending on the city. Most places require one for a full replacement.

How the estimate compares with other sources

The material line uses HomeGuide’s installed price per square foot, and the headline is the midpoint of the low and high totals. Other sources read on Oct 27, 2026 put the same job in a similar band: HomeGuide $4 to $6 per sq ft for architectural shingles, Modernize $6.00 to $9.00 (and $4.50 to $7.50 for 3-tab), Fixr $3.75 to $11 with a $4.75 average, and Angi $4 to $11. For a whole roof, Fixr gives a $10,000 average ($7,500 to $14,000), Angi $9,610 ($5,903 to $13,378) and HomeGuide $5,700 to $16,000.

The default 2,236 sq ft architectural roof comes out at about $11,180 at the midpoint before the permit, a little above the Fixr and Angi averages, which cover roofs of every size. All of these are national figures; prices vary by region, roof height and access.

Repair or replace?

HomeGuide’s rule of thumb is to consider a repair if less than 25% of the roof is damaged, the repair costs less than 30% of a new roof, and the roof is under 20 years old. Angi’s version is simpler: once a repair would cost half of a replacement, replace. Age matters because asphalt shingles last roughly 15 to 30 years, metal 30 to 80 years or more, and tile and slate far longer.

Insurance usually covers sudden storm or accident damage, not wear and tear, so a claim will not pay for a roof that simply wore out. If you are counting materials for a DIY reroof of a shed or garage, the roofing calculator turns the same area into bundles of shingles, underlayment and ridge cap. Re-siding too? Use the siding calculator.

Sources & assumptions

How this calculator gets its numbers. Full method: our methodology.

• Installed prices per square foot of roof surface are national estimates that vary by region, from HomeGuide (November 2025): its reshingle, metal, tile, slate and flat-roof tables. They cover material and installation, and HomeGuide’s whole-house figures (for example $6,700–$13,400 for a 2,000 sq ft one-story house) equal roof area × $3–$6, so removing one old layer is treated as included.
• Roof area from the footprint = footprint × √(1 + (pitch ÷ 12)²). HomeGuide’s table uses a 2,235 sq ft roof for a 2,000 sq ft single-story house at 6:12, which this reproduces.
• Each extra layer to tear off is priced at HomeGuide’s removal rate: $1–$3 per sq ft for shingles or metal, $2–$5 for tile or slate. That the rate applies per layer is our assumption.
• Extras use HomeGuide figures: decking $2–$5 per sq ft, permit $100–$500, drip edge $1.50–$3 per linear ft, gutter replacement $12–$25 per linear ft, skylight replacement $800–$2,400, roof vents $200–$700 each, full flashing replacement $400–$1,000. The steep-roof allowance ($1,000–$3,000) is Angi’s.
• The headline is the midpoint of the low and high totals. HomeGuide lists wood shakes at $7–$15 per sq ft in one table and $25–$30 in its text, so the calculator uses its cedar/wood reshingle row ($5–$12) instead.

Sources

1. Fixr, How Much Does a Roof Replacement Cost? [2026 Data]. Updated Feb 4, 2026: about $10,000 average, $7,500–$14,000 typical; $4.75 per sq ft average ($3.75–$11).
2. Modernize, Roof Replacement Cost Calculator. Updated Oct 6, 2026: 3-tab shingles $4.50–$7.50 and architectural $6.00–$9.00 per sq ft installed.
3. HomeGuide, How much does a roof replacement cost?. $5,700–$16,000 average; $3–$6 per sq ft installed; roof size table at 6:12; installed cost per sq ft by material (3-tab $3–$5, architectural $4–$6, premium $5–$7, metal shingles $6–$14, standing seam $9–$16, concrete tile $7–$19, clay $8–$25, slate $10–$30, EPDM $3.50–$10, TPO $4–$10); tear-off $1–$3 or $2–$5 per sq ft; decking $2–$5; permits $100–$500; pitches over 6:12 need more labor.
4. Angi, How Much Does Roof Replacement Cost? [2026 Data]. Updated Oct 22, 2026: $9,610 national average, $5,903–$13,378 typical, $4–$11 per sq ft; an unusually steep pitch adds $1,000–$3,000; permits $100–$1,400; inspections about $240.
5. GAF, How Many Bundles of Shingles Are in a Square?. A roofing square is 100 sq ft of roof surface.

Last reviewed October 27, 2026. Installed prices vary by region, contractor and job conditions; a written local bid wins.