Understanding your result
The headline is the cost per year of the roof, with the installed cost, the life and the maintenance. The stats show the installed cost, the life and the cost per square per year; the bars compare the two materials.
The installed cost can come from the replacement cost calculator or a quote; the expected replacement date from the replacement planner. Repairs on an old roof are priced by the repair cost calculator.
How we calculate this
The life figures are the mid-points of survey ranges, collected in the lifespan guide.
The assumptions behind the numbers
| Assumption | Default | Where it comes from |
|---|---|---|
| Life by material | three-tab 15–20; architectural 25–30; designer 30–40; exposed metal 30–45; standing seam 40–70; cedar 25–30; synthetic 40–50; concrete tile 40–60; clay tile 50–100; slate 75–100; membrane 20–30 years | InterNACHI standard life expectancy chart; NAHB study of life expectancy of home components |
| Installed cost | survey mid-points by material | 2025 published cost surveys |
| Maintenance | $150 per year | A judgement for inspections and small repairs |
Assumptions last reviewed October 7, 2026.
The calculator does not model resale value, energy savings or financing. The repair or replace guide covers timing.
Two worked examples
Architectural shingles against standing seam
22 squares, survey mid-points, $150 maintenance.
- Architectural: $13,750 ÷ 27.5 + $150 = $650 a year
- Standing seam: $40,700 ÷ 55 + $150 = $890 a year
- Shingles $240 a year cheaper
Three-tab against architectural
18 squares.
- Three-tab: $8,100 ÷ 17.5 + $150 = $613 a year
- Architectural: $11,250 ÷ 27.5 + $150 = $559 a year
- Three-tab $54 a year dearer despite the lower price
Where to find your inputs
Installed cost. From a quote or the replacement cost calculator.
Life. The survey range, adjusted for your climate and ventilation.
Maintenance. Your own records, or $100 to $300 a year.
Common mistakes
- Comparing purchase prices only. Divide by life.
- Ignoring how long you will stay. Long life only helps if you use it.
- Survey life as a promise. It is a range.
- Skipping maintenance. Cedar needs it most.
- Ignoring ventilation. Poor ventilation shortens asphalt life.
- No inflation. This sum ignores it.
Questions people ask
- How long does a roof last?
- Industry surveys put three-tab asphalt at 15 to 20 years, architectural at 25 to 30, exposed-fastener metal at 30 to 45, standing seam at 40 to 70, cedar at 25 to 30, concrete tile at 40 to 60, clay tile at 50 to 100 and slate at 75 to 100 or more. Climate, ventilation and installation move these by years.
- Which roof is cheapest per year?
- With survey mid-points on 22 squares and $150 of yearly maintenance, architectural shingles cost about $650 a year and standing seam about $890. Three-tab, cheaper to buy, costs more per year than architectural because it lasts ten years less.
- Is a metal roof worth it?
- Per year of life, standing seam usually costs more than architectural shingles at survey prices, but it needs replacing once where shingles need it twice; it pays when you stay long enough to use the life, or value low maintenance and appearance.
- Should I include maintenance?
- Yes: inspections, cleaning, sealant and small repairs. Asphalt and metal are low; cedar needs cleaning and treatment; tile and slate need occasional broken-piece replacement.
- Does this account for inflation?
- No. It is a simple cost per year. Counting the time value of money makes long-lived roofs look somewhat less attractive than this simple sum.
- Repair or replace?
- Compare a repair's cost divided by the years it buys with the new roof's cost per year. The repair-or-replace guide walks through it.