By The Roofing Brief Team. Last reviewed: October 2026.
Gutter profiles are the cross-sectional shapes of a gutter, and the five you will meet on North American homes are K-style, half-round, fascia (straight-face), box and ogee. Profile and size together set capacity: under 2021 IPC Table 1106.6, a 5 inch semicircular (half-round) gutter at 1/8 inch per foot of slope is rated for 74 gallons per minute and a 6 inch for 110 gpm, while a 5 inch K-style holds roughly 40 percent more cross-section than a 5 inch half-round. Profile also decides the hangers, the look against your fascia, and the price: HomeGuide lists 5 inch aluminum K-style material at $1 to $4 per linear foot against $3 to $5 for half-round.
What a gutter profile is (and why it matters)
A gutter profile is the shape of the trough seen end-on, not its material or its width. Two gutters can both be 5-inch aluminum and still move very different amounts of water, because a K-style trough is deeper than a half-round of the same nominal size. Profile sets capacity, the hardware that fits, how easily debris clings, and the look along your roofline.
Profile, material and size are three separate choices: a 5 inch aluminum K-style and a 5 inch copper half-round share a nominal size and nothing else. Pick the shape here, the metal in gutter materials compared, and the size in gutter sizes and capacity. For the parts involved, see what a gutter actually is.
The five main gutter profiles at a glance
Five profiles cover almost every house. K-style is the U.S. default (HomeGuide: “most residential homes use 5-inch K-style gutters”), half-round suits period homes in 5, 6 and 7 inch sizes, fascia gutters show up on newer builds, box gutters run 7 to 24 inches wide on large or commercial roofs, and ogee is the standard decorative term in the UK and Australia.
| Profile | Shape end-on | Look | Common sizes | Best for |
|---|---|---|---|---|
| K-style | Flat back, decorative front like crown molding | Modern, common | 5 in, 6 in | Most homes, high capacity per width |
| Half-round | Semicircular U trough | Traditional, classic | 5 in, 6 in, 7 in | Historic and higher-end homes |
| Fascia (straight-face) | Tall flat front, deep channel, mounts as the fascia | Clean, flush | Custom depth | New builds, modern trim, no fascia board |
| Box | Rectangular channel, often built into the roof | Hidden or industrial | 7 in to 24 in and up | Commercial and very large roofs |
| Ogee (European) | S-curved front, high-volume | Ornamental, period | 4 in to 6 in | UK and period homes, heavy rainfall |
Below the 5 inch residential sizes, sheds, mobile homes and tiny houses often use narrow systems covered in our guide to mini gutters.
K-style gutters
K-style is the most common residential profile in the United States, with a flat back that sits against the fascia and a curved front face that resembles crown molding. The angular shape gives it a deeper channel than a half-round of equal width, so a 5-inch K-style carries roughly 40 percent more water than a 5-inch half-round. It comes in 5-inch and 6-inch sizes and runs as a seamless one-piece length off a forming machine; one supplier’s 5-inch section measures 5 in across the top, about 3-1/2 in high and 3-1/8 in across the bottom (GutterAll spec).
The trade-off is the inside corners. Debris and grit collect where the front face meets the flat 3-1/8 inch floor, so K-style needs periodic cleaning with the right tool like any open gutter. It stays the default because 5-inch aluminum K-style material runs $1 to $4 per linear foot (HomeGuide, October 2023) and it hangs on hidden brackets that keep the face clean.
Half-round gutters
Half-round gutters are a simple semicircular trough, the classic U-shape seen on older and higher-end homes. They hold less water than a K-style of the same nominal width because the round bottom is shallower, but the smooth interior sheds debris and rinses clean. Standard diameters are 5-inch, 6-inch, and 7-inch, and copper and painted steel versions are common on period restorations.
Half-round needs its own hardware: exterior brackets or hangers sized to the round, not the hidden clips used on K-style. HomeGuide’s gutter installation guide (October 28, 2025) says half-round adds $1 to $2 per linear foot to installation, and its aluminum guide lists half-round material at $3 to $5 per foot for 5-inch and $5 to $6 for 6-inch, so compare quotes from more than one gutter company. For the direct trade-off, see K-style versus half-round head to head.
Fascia (straight-face) gutters
A fascia gutter integrates the gutter and the fascia board into one deep component with a tall flat front, so it replaces the fascia rather than hanging off it. Suppliers also sell it as straight face gutters. Because the channel is deep and wide, it moves a large volume for a clean, flush look with no visible curve. It is common on newer and contemporary homes, especially in the western United States.
Fascia gutters are usually formed to a custom depth on site and fastened straight to the rafter tails, which makes them a structural detail rather than a bolt-on. Replacement is less of a drop-in swap than K-style: if the face height changes by even 1/2 inch, the soffit, drip edge and end caps have to change with it, so measure the face height and channel depth before ordering.
Box gutters
Box gutters are large rectangular channels, often built into the roof structure behind a parapet or along a valley rather than hung on the edge. Widths run from about 7 inches to 24 inches and beyond, so they carry far more water than any residential profile. They are standard on commercial buildings, warehouses, and very large or historic homes.
Because a built-in box gutter is part of the roof, a failure leaks into the structure instead of down the outside wall. Size it like a roof drain: the 2021 IPC table rates a 3 by 5 inch rectangular gutter at 157 gpm at 1/4 inch per foot and a 4-1/2 by 6 inch at 348 gpm. Modern exposed box profiles can also mount on the fascia or sit semi-recessed, as DuraGutter’s box profile page shows. For how built-in boxes are waterproofed and repaired, see the full guide to box gutters.
Ogee and European profiles
Ogee is the standard gutter profile term in the UK and Australia, where the trade calls them guttering profiles rather than gutter profiles. It describes an S-curved front face that is decorative and high-capacity at the same time; FloPlast’s 110 mm Niagara ogee, for example, is 80 mm (about 3-1/8 in) deep against 52 mm (about 2 in) for its 112 mm half-round. It overlaps with what the U.S. market calls K-style: HomeGuide groups “K-style or ogee gutters” as the most common type. For the plain definition of the word, see our guide to gutter meaning.
If you are matching a period property or ordering from a British supplier, ask for the profile by its regional name and its measured width, because the capacity gap is large at the same nominal size. FloPlast’s technical data, calculated to BS EN 12056-3 with the outlet at the end of a level run, gives the figures below.
| UK profile (FloPlast) | Width x depth | Max flow, end outlet, level | Roof area served | Source |
|---|---|---|---|---|
| Half Round | 112 x 52 mm | 0.92 litres/sec | 44 m² | FloPlast Rainwater Systems Technical Data (rev. 06/09/2019) |
| Square Line | 114 x 60 mm | 1.70 litres/sec | 81 m² | |
| Hi-Cap (deepflow) | 115 x 75 mm | 2.05 litres/sec | 98 m² | |
| Niagara (ogee) | 110 x 80 mm | 2.40 litres/sec | 115 m² |
Gutter profile capacity compared
Capacity comes from cross-sectional area and slope, set by profile and size together. The U.S. code number is 2021 IPC Table 1106.6, which rates semicircular and rectangular gutters in gallons per minute by slope. To turn your roof into gpm, IPC Equation 11-1 multiplies 0.0104 by the rainfall rate in inches per hour and the roof area in square feet; local 100-year, 1-hour rainfall comes from NOAA Atlas 14.
| Profile and size | Cross-section (geometry) | IPC 1106.6 capacity | Roof area at 3 in/hr | Roof area at 5 in/hr |
|---|---|---|---|---|
| Half-round, 5 in | 9.8 sq in (half of a 5 in circle) | 74 gpm at 1/8 in per ft | About 2,370 sq ft | About 1,420 sq ft |
| Half-round, 6 in | 14.1 sq in | 110 gpm at 1/8 in per ft | About 3,530 sq ft | About 2,120 sq ft |
| K-style, 5 in | About 14 sq in (5 in top, 3-1/8 in floor, 3-1/2 in high) | Not listed; size by maker chart | Not listed | Not listed |
| Rectangular (box), 3 x 5 in | 15 sq in | 157 gpm at 1/4 in per ft | About 5,030 sq ft | About 3,020 sq ft |
| Rectangular (box), 4-1/2 x 6 in | 27 sq in | 348 gpm at 1/4 in per ft | About 11,150 sq ft | About 6,690 sq ft |
Roof area = capacity divided by (0.0104 x rainfall rate); for example, 74 gpm divided by (0.0104 x 3 in/hr) is about 2,370 sq ft. The K-style cross-section treats the profile as a trapezoid from the GutterAll dimensions; the molded front adds or removes a little. The table rates the gutter alone; each downspout has its own limit.
Downspouts cap the system too. IPC Table 1106.3 rates a 2 by 2 inch leader at 30 gpm, a 2 by 4 inch at 92 gpm and a 3 inch round at 92 gpm, so a 74 gpm half-round run feeding one 2 by 2 leader is limited to 30 gpm at that outlet. Where each outlet goes and how it connects to the run is covered in our step-by-step downspout installation guide.
Gutter profile dimensions: how sizes are measured
A gutter’s nominal size is its width across the top opening, so a 5-inch gutter measures 5 inches from the front lip to the back. Depth, bottom width and front height are separate dimensions, and they change with the profile and the manufacturer. Two gutters sold as 5-inch can hold different volumes, so compare the full cross-section, not the size label.
Four measurements define a gutter profile’s dimensions:
- Top width: the opening across the top, and the number the gutter is sold by.
- Height (depth): how deep the trough runs from the top edge to the bottom.
- Bottom width: the flat floor of the channel on K-style, fascia and box profiles. Half-round has no flat floor.
- Front lip: the rolled or folded bead along the top of the front face, which hangers and guards hook into.
As one example, a supplier’s 5-inch K-style aluminum section is listed at a 5 in top width, about 3-1/2 in height, 3-1/8 in bottom width and a 1/2 in front lip (GutterAll 5-inch K-style spec). Other manufacturers form the same nominal size to slightly different depths, so measure before ordering matching parts.
| Profile | Common sizes | What to measure |
|---|---|---|
| K-style | 5 in, 6 in | Top width, back height, bottom width |
| Half-round | 5 in, 6 in, 7 in | Width across the top of the round |
| Fascia (straight-face) | Custom depth | Face height and channel depth |
| Box | 7 in to 24 in and up | Inside width and depth |
| Ogee | 4 in to 6 in | Measured width plus the supplier’s profile name |
End caps, outlets and hangers are made to one profile and one set of dimensions; a 5 inch K-style end cap will not close a 6 inch run or a 5 inch half-round. Take your measurements from a cut end or an end cap, to the nearest 1/8 inch, then match them to the parts that fit the run. For sizing a new system to your roof area, use the charts in gutter sizes and capacity.
How to identify the gutter profile you already have
You can name your existing profile by looking at the front face and the end cap from a ladder, then confirming with one tape measurement across the top (5, 6 or 7 inches on most homes). The front shape is the tell: a molded curve is K-style or ogee, a round U is half-round, a tall flat face is fascia, and a wide rectangle is box.
- Look at the front face from the side. Crown-molding curve: K-style. Half-circle: half-round. Tall flat panel: fascia. Square box: box.
- Check the back. A flat back nailed to the fascia points to K-style or fascia. A round back on brackets points to half-round.
- Measure the opening. Width across the top tells you the size (5, 6, or 7 inch) once you know the shape.
- Note the hangers. Hidden clips inside mean K-style. Exterior brackets under the round mean half-round.
- Find a seam or joint. A continuous run with no lengthwise seams was formed on site; sectional pieces snap together at joints.
How to choose a gutter profile for your house
Choose by roof area, rainfall, architecture and budget, in that order. Capacity is the hard constraint: work out the gpm with IPC Equation 11-1 (0.0104 x rainfall in inches per hour x roof area in square feet), then pick a profile whose rated capacity clears it. Style and cost decide between profiles that all clear the bar.
| Situation | Start with | Threshold | Source |
|---|---|---|---|
| Standard home, roof area per run under about 1,400 sq ft at 5 in/hr | 5-inch K-style | Needs under 74 gpm; 5 in K-style holds more than a 5 in half-round | IPC 1106.6; HomeGuide |
| Run draining 1,400 to 2,100 sq ft at 5 in/hr | 6-inch K-style or 6-inch half-round | 6 in half-round rated 110 gpm at 1/8 in per ft | IPC 1106.6 |
| Historic or period home | Half-round (copper or steel) | Adds $1 to $2 per foot to install | HomeGuide, Oct 2025 |
| Modern or new build, no fascia board | Fascia (straight-face) or modern box | Custom-formed to the eave; measure face height | Maker specs |
| Commercial roof or run over about 3,000 sq ft at 5 in/hr | Box gutter | 3 x 5 in rated 157 gpm, 4-1/2 x 6 in 348 gpm at 1/4 in per ft | IPC 1106.6 |
| UK or Australian supplier | Ogee or deepflow over standard half-round | 2.40 or 2.05 l/s vs 0.92 l/s at a level end outlet | FloPlast technical data |
How profile changes cost and hardware
Profile drives both the hardware you need and the installed price. K-style is cheapest because it forms fast and hangs on hidden clips; half-round adds $1 to $2 per foot for its brackets; fascia and box are custom-formed and quoted per job. The figures below are dated and named so you can check them.
| Profile | Price | What it covers | Source |
|---|---|---|---|
| Seamless aluminum K-style, installed | $6 to $12 per linear foot; $6.29 to $10.45 | Gutter, downspouts, labor | HomeGuide aluminum guide, Oct 2023; HomeWyse, May 2026 |
| Aluminum K-style, material only | $1 to $4 (5 in); $2 to $5 (6 in) per foot | Gutter stock only | HomeGuide aluminum guide |
| Aluminum half-round, material only | $3 to $5 (5 in); $5 to $6 (6 in) per foot | Gutter stock only | HomeGuide aluminum guide |
| European-style aluminum, material only | $5 to $7 (5 in); $7 to $9 (6 in) per foot | Gutter stock only | HomeGuide aluminum guide |
| Half-round install premium | +$1 to $2 per linear foot | Brackets and slower install | HomeGuide installation guide, Oct 28, 2025 |
| 6 in instead of 5 in | +$1 to $2 per linear foot | Larger stock and hangers | HomeGuide installation guide |
| Fascia and box gutters | No national figure published in these guides | Custom-formed; quoted per job | Get two written quotes |
Hangers are not interchangeable across profiles, so a profile change is a full replacement, not a swap of the trough. On a 150 foot house, the HomeGuide half-round premium alone adds $150 to $300 before new brackets, end caps, and outlets sized to the shape you pick.
Frequently asked questions
What is a gutter profile?
A gutter profile is the cross-sectional shape of the trough seen end-on, separate from its material or width. The five common profiles are K-style, half-round, fascia (straight-face), box and ogee. Profile sets how much water the gutter carries: a 5 inch half-round is rated 74 gpm at 1/8 inch per foot under IPC Table 1106.6, and a 5 inch K-style holds roughly 40 percent more cross-section.
What is the most common gutter profile?
K-style is the most common residential gutter profile in the United States. It has a flat back against the fascia and a curved front face that resembles crown molding. The angular shape gives it a deeper channel than a half-round of the same width, so it moves more water for a lower installed cost, which is why builders default to it.
Which gutter profile holds the most water?
Box gutters hold the most: IPC Table 1106.6 rates a 4-1/2 by 6 inch rectangular gutter at 348 gpm at 1/4 inch per foot, against 110 gpm for a 6 inch half-round at 1/8 inch per foot. Among residential profiles, a 6-inch K-style carries the most. At any given width, K-style beats half-round because its flat floor and taller back give more cross-sectional area.
What is the difference between K-style and half-round gutters?
K-style has a flat back and a molded front face and holds roughly 40 percent more water than a half-round of the same nominal width. Half-round is a semicircular U-shape that looks traditional, sheds debris from its smooth interior, and needs exterior brackets. K-style hangs on hidden clips and costs less; half-round is common on historic homes.
What is a fascia gutter?
A fascia gutter integrates the gutter and the fascia board into one deep component with a tall flat front, so it replaces the fascia rather than hanging off it. It is formed to a custom depth on site and fastened to the rafter tails, so the face height and channel depth have to be measured to the nearest 1/8 inch before a replacement is ordered.
Which gutter profile is best for my house?
Choose by roof area and rainfall first: multiply 0.0104 by your rainfall rate in inches per hour and the roof area per run in square feet to get gpm, then pick a profile rated above it in IPC Table 1106.6. A standard home usually starts with 5-inch K-style; runs over about 1,400 sq ft at 5 in/hr move up to 6-inch. Historic homes suit half-round, modern builds suit fascia, and commercial roofs use box gutters.