Enter a repair cost and a full replacement cost to compare.
Guidance based on cost ratio only. A professional inspection is the reliable way to confirm the repair scope and check for hidden damage.
Data sources
Repair ranges are cross-checked across 2026 trade cost guides, then scaled to your region and roofing material. Expected roof life uses the InterNACHI life-expectancy chart.
Every roofing calculator
Sixteen tools for pricing, measuring, and planning a roof.
The repair-or-replace call, explained
Every figure below comes from the same verified data the calculator runs on.
Repair or replace? The 30 and 50 percent rules
Strip the decision down and it's a ratio. When a repair costs less than about 30 percent of a full replacement, repairing usually wins: you're buying meaningful roof life for a fraction of the money. When the repair reaches about 50 percent, replacing usually wins, because you'd be spending new-roof money without getting a new roof. Between the lines is a genuine judgment call. This calculator runs your two numbers against those cross-checked thresholds. No replacement figure yet? The roof cost calculator builds a local one in about a minute.
Repair, replace, or judgment call: reading your result
Under 30 percent, fix it and move on, unless the roof is already near the end of its life. Over 50, get replacement bids: even if the repair technically works, you're pouring money into a roof that's telling you something. In between, this is exactly what a $100 to $400 professional inspection is for. It turns the gray zone into a diagnosis, and it's cheap insurance against paying for major surgery on a roof with hidden problems.
Roof age is the tiebreaker
The ratio is about money. Age is about what the money buys. A $1,200 repair on a 5-year-old architectural asphalt roof buys two more decades of service. The same repair at 25 years, on a material with a typical 28-year life, is patching something that's nearly done either way. Once a roof passes about 20 years, replacement is usually the smarter long-term call. Add your roof's age and material above and the calculator reads your position against the typical lifespan for that material, using the same InterNACHI-anchored figures as the lifespan tool. Repeated repairs are the other aging signal: when fixes become a subscription, each one is buying less time.
Frequently asked questions
Is it better to patch a roof or replace it?
For contained damage on a roof with life left, patch it: minor repairs typically run $150 to $600 and moderate ones $600 to $2,000. For widespread damage, structural problems, or repairs above about half of replacement cost, replace. In between, inspect first.
Can I replace just half the roof?
It's rarely recommended. New and old shingles won't match, warranties get messy across the seam, and the old half keeps aging on schedule, so you often pay for mobilization twice. Section repairs make sense. Half-replacements usually don't.
Does insurance change the math?
It can flip it completely. If storm damage is covered, your real cost may be just the deductible, which makes replacement far more attractive than the raw ratio suggests. The insurance claim calculator shows how a payout would break down.