You are paying for the search as much as the metal
A flashing leak rarely shows up under the flashing. Water slips past a lifted corner or a rusted step, runs down the deck or along a rafter, and drops onto the ceiling somewhere downslope. The roofer starts from the stain, works uphill to the nearest wall, chimney or pipe, and lifts shingles along the flashing line until the failed piece turns up. The timeline on this page gives that search its own line, ahead of any new metal going in.
The calculator scales the job in a straight line, so a longer run costs proportionally more at about $17.23 to $26.77 per foot. Real quotes for short runs do not work that way. The ladder, the search and the cleanup cost much the same for three feet as for thirty, and most roofers bill a small repair at their minimum service charge rather than by the foot.
Which piece has failed
Step flashing runs up a wall or the side of a chimney that follows the slope of the roof. It is a stack of separate L-shaped pieces, one tucked under each shingle course and each lapping the piece below, so water is handed from one to the next and back onto the shingles. Rusted or missing steps are the repair this estimate is built around.
Apron flashing is a single continuous piece along a joint that runs level across the slope: the downhill face of a chimney or dormer, or the wall where a lower roof stops against the house. The long run is simple. The corners, where it has to fold into the step flashing coming down the sides, are the hard part to get watertight.
Counter flashing caps the top edge of the step or apron flashing so water cannot get behind it from above. On brick it is set into a mortar joint; on a sided wall, the siding and the house wrap behind it do the same job. When counter flashing pulls out of its joint, the steps below can be perfect and the wall will still leak. On a chimney that is its own job, priced at chimney flashing repair.
Pipe boots are the cones around plumbing vents, with a rubber collar that grips the pipe. The collar cracks in the sun long before the shingles around it wear out. A boot is replaced as one part rather than measured in feet, so this calculator does not fit it; expect a short visit billed at the minimum charge. The roof flashing guide covers every type by where it sits.
Why a bead of caulk is not a repair
The cheapest answer to a leak at a wall is a tube of sealant run along the top of the old flashing. It can stop the drip for a season. Flashing keeps water out by overlap: each piece sits under the one above, so water has to run uphill to get in. Sealant keeps water out by sticking, and metal, brick and siding all expand and shrink at different rates through every hot afternoon and cold night. The bead is stretched every day until it lets go along one edge, and then the gap it was hiding is open again, sometimes with the caulk now steering water into it.
The estimate does carry $16 to $40 of sealant, but for small jobs: covering nail heads that end up exposed and closing the joint along the top of the counter flashing. None of the waterproofing depends on it. If a quote describes the repair mainly as sealing or recaulking, ask which pieces of metal are being replaced, because that is a shorter-lived job than the one priced here.
When the shingles have to come up too
Step flashing lives under the shingles, so every step flashing repair lifts the shingles along the wall. On a roof that is still flexible, they bend up, the new pieces slide in and the same shingles are nailed back down. The estimate assumes that and includes no new shingles. On an older roof, or on a cold day, shingles crack as their sealing strips are broken, and a bundle of replacements gets added. A weathered roof is rarely a perfect color match, so the repair may show.
With the shingles up, the felt underneath is often found rotted where the water was getting in, which is what the $6 to $17 underlayment patch covers. If the decking itself has gone soft, that is a separate roof decking repair.
The wall side can add work too. The upright leg of step flashing runs up behind the siding, so with vinyl or wood lap siding the lowest course or two may need removing to get at it, and stucco has to be cut and patched. Neither is in this estimate, and on stucco the patching can be a bigger job than the flashing. On a roof only a few years from replacement, weigh all this against new flashing put in with the next roof, which costs much less per foot because nothing has to be lifted.