Roof Lifetime Cost Calculator
Last reviewed How we calculate
The cheapest roof to install is not always the cheapest roof to own. A roof that lasts twice as long can cost less over the years even if its price is higher. This compares two options by what they cost per year and over a period you choose.
Compare roofing options over time
Compare two roofing options by cost per year and total cost over a period of years.
This calculator needs JavaScript to work. The measurements below are the ones you would need to do the sum by hand.
Difference over the period
- Option A, cost per year
- Option B, cost per year
- Option A, total over the period Every roof bought within the period, plus upkeep.
- Option B, total over the period
- Option A, roofs bought
- Option B, roofs bought
Option A costs less over this period.
Option B costs less over this period.
The two options cost the same over this period.
There is no allowance for inflation, interest, or the value of a roof with years left at the end of the period, and the lifespans are yours to set. Treat it as a way to see how lifespan changes the picture, not as a forecast.
How the calculation works
Cost per year is the installed cost divided by the lifespan, plus any yearly upkeep. The total over the period counts every roof you would have to buy within it: a 25-year roof over 40 years means buying two. Upkeep is added for every year of the period.
A worked example
These figures are examples. Option A costs 15,000 and lasts 25 years, which is 600 a year. Option B costs 28,000 and lasts 50 years, which is 560 a year. Over 40 years, A has to be bought twice, for 30,000, while B is bought once, for 28,000, so B comes out 2,000 cheaper despite nearly double the price.
What it leaves out
It ignores inflation, the interest the difference in price could earn, and the value of a roof that still has years left at the end of the period. Real lifespans also depend on climate, installation quality and upkeep, and on whether you will still own the house. Treat the result as a way to see how lifespan changes the picture rather than as a forecast.
Frequently asked questions
Is a metal roof cheaper in the long run?
It can be, because it may last far longer than asphalt, but it depends on the prices and lifespans in your quotes and how long you keep the house. Enter your own figures to see.
Why does it count a whole roof even if it is only partly used?
Because you pay for a whole roof when you replace one. The calculator counts every roof you would have to buy within the period, without credit for years left at the end.
Does it allow for resale value or inflation?
No. It leaves out inflation, interest and the value a newer roof adds when you sell, so treat it as a comparison rather than a forecast.