Roof Replacement Cost Estimator
Last reviewed How we calculate
A roof replacement quote is built from a handful of parts: the roofing itself, tearing off the old roof, repairs to the deck underneath, extras such as flashing and vents, and permits and disposal. This puts those parts together for your roof, using prices you supply.
Roof replacement cost from your own prices
Your local prices multiplied by your roof: roofing, tear-off, deck repairs, extras and contingency.
This calculator needs JavaScript to work. The measurements below are the ones you would need to do the sum by hand.
Estimated total In the currency of the prices you entered.
- Roofing, with waste
- Tear-off
- Deck repairs
- Other items, permit and disposal
- Contingency
- All-in price per square
This multiplies your prices by your roof; it does not supply prices. An online average says little about your roof, your area or your contractor, so use rates from real local quotes. The quote comparison calculator helps line those quotes up.
Why it asks for your prices
Roofing prices depend heavily on where you live, the material, the pitch, how easy the roof is to reach and how busy contractors are. A national average applied to your roof can be wrong by a wide margin in either direction, so this calculator does not guess one. Take the price per square from a local quote or a contractor price list, and it will show what that means for your whole job.
How the calculation works
The roofing is the roof area in squares, with waste, times the installed price per square. Tear-off is the squares, times the layers coming off, times the tear-off price. Deck repairs are the sheets replaced times the price per sheet. Extras, permits and disposal are added as they are, and a contingency percentage goes on the total.
A worked example
These prices are invented to show the arithmetic, not to suggest what a roof should cost. For a 1,250 sq ft roof with 10 per cent waste at 500 a square, the roofing comes to 6,875. Tearing off one layer at 100 a square adds 1,250, five deck sheets at 60 add 300, and extras plus permit and disposal add 1,500. With a 10 per cent contingency the total is about 10,918, or about 873 a square all in.
Why the contingency matters
Nobody knows the condition of the deck until the old roof is off. Rotten sheathing, damaged rafter tails and hidden leaks are common, and most contracts price them as extras. Setting money aside for them in advance is what keeps a roof replacement on budget.
Frequently asked questions
Why does this calculator not give a price?
Roofing prices vary widely by area, material, roof and contractor, and a national average can be far off for your roof. Enter the price per square from a local quote, and the calculator shows what that means for the whole job.
What costs are often missing from a roofing estimate?
Deck repairs, extra layers of old roofing, new flashing, ventilation, permits and disposal are the usual ones. Ask how each is priced before you sign.
How much contingency should I allow?
10 per cent is a common planning figure. Older roofs, roofs with a history of leaks and roofs with more than one layer to remove justify more.