By The Roofing Brief Team. Last reviewed: October 2026.
To cut a gutter downspout, match the tool to the metal, mark a square line all the way around, cut slowly, then file the burr off the edge. Aluminum downspouts cut cleanly with aviation snips or a fine-tooth hacksaw; double-cut downspout snips such as the Malco Max2000 (model M2004) are rated by Malco for aluminum up to .040 in, about twice the .019 in wall of a standard 2×3 downspout. Steel, galvanized, and copper hold up better under a hacksaw or a reciprocating saw with a metal blade. Vinyl cuts with a hacksaw or a PVC pipe cutter. Most factory downspouts ship in 10-foot sticks in 2×3-inch or 3×4-inch rectangular profiles, so nearly every install needs at least one cut to length. If you are fitting a whole run rather than trimming one piece, follow the full downspout installation sequence from outlet to extension alongside this cutting guide. If you are weighing a full replacement instead, our gutter replacement cost breakdown by material and length puts the numbers side by side.
What tool should you use to cut a downspout?
The right cutting tool depends on the downspout material and wall thickness, not on the brand. Aluminum, the standard on most residential and seamless gutter systems, is soft enough for hand snips: Englert lists its 2×3 downspout at .019 in aluminum in 10 ft lengths. Steel and copper resist snips and dull them, so a saw fitted with the same bi-metal blades used for cutting metal roofing gives a straighter, safer cut. Vinyl cracks if you force snips through it, so a saw or pipe cutter is safer. Pick the tool first, because the wrong one leaves a crushed, out-of-round end that will not slide into an elbow or the next section.
| Downspout material | Typical gauge/weight | Best tool | Avoid |
|---|---|---|---|
| Aluminum (most residential) | 0.019 to 0.032 in | Aviation (tin) snips, or fine-tooth hacksaw (24-32 TPI) | Abrasive wheels that melt the finish |
| Steel / galvanized | 26-28 gauge | Hacksaw or reciprocating saw with a bi-metal blade | Snips, which distort the profile |
| Copper | 16 oz | Fine-tooth hacksaw or a cold saw | Angle grinder, which heat-scars the patina |
| Vinyl / PVC | n/a | Hacksaw, miter saw with fine blade, or PVC pipe cutter | Snips, which crack the wall in cold weather |
A hacksaw with a 32 TPI bi-metal blade (one tooth every 1/32 in) is the one tool that handles every material acceptably, which is why most homeowners with a single project reach for it. Aviation snips are faster on aluminum but only aluminum. A sliding miter saw with a fine-tooth finish blade run at moderate speed gives the cleanest square end on rectangular downspouts, and it repeats the same length across a run of pieces. Not sure which profile you have? Our guide to measuring gutter and downspout size covers 2×3 versus 3×4 and round profiles.
Downspout snips and cutters compared
Capacities below come from each maker’s published spec. Compare them with the wall thickness of your downspout in the stock table further down: a tool rated at .040 in aluminum has headroom on .019 and .024 in stock.
| Tool (model) | Type | Published capacity or spec | Best use on downspouts | Source |
|---|---|---|---|---|
| Malco Max2000 (M2004) | Double-cut aviation snips, 3 blades | Aluminum .040 in, copper .034 in, galvanized .034 in, mild steel .030 in | Cutting across a 2×3 or 3×4 aluminum downspout without flattening the profile | Malco spec page |
| Midwest Stovepipe and Duct Cutter (MWT-P1) | Double-cut snips | Removes a 3/16 in strip from the center of the cut, up to 1-1/4 in per stroke | Repeated field cuts by a gutter crew; leaves 2 finished edges | Midwest 2025 catalog, p. 31 |
| Malco RedLine 5-Blade Crimper (C5R) | Crimper, not a cutter | 1-5/8 in double crimp; aluminum .035 in, copper .023 in, galvanized 24 ga (.028 in); 7 to 1 leverage | Shrinking the cut end so it nests in an elbow or the next section | Malco spec page |
| Midwest 5-Blade Crimper (MWT-C5) | Crimper | Crimps ends up to 1-5/8 in throat depth | Same job as the C5R | Midwest 2025 catalog, p. 31 |
| Hacksaw, 32 TPI bi-metal blade | Saw | Fine pitch for thin-wall tube and sheet | One-off cuts in any material, including steel and copper | Editorial: general blade-selection practice |
Which downspout cutting tool fits your job
| If your downspout is | And you need | Use | Why |
|---|---|---|---|
| Aluminum, .019 or .024 in | 1 to 3 cuts | Fine-tooth hacksaw (32 TPI) or aviation snips | Both are well inside the thickness; no special tool to buy |
| Aluminum, .019 or .024 in | A full run or repeat lengths | Double-cut downspout snips (Malco M2004 class) or a miter saw with a fine finish blade | Double-cut snips remove a strip instead of folding the wall, so the profile stays square |
| Galvanized or Galvalume steel, 24 to 30 ga | Any cut | Hacksaw or reciprocating saw with a bi-metal blade | Snips distort steel profiles and dull fast; Malco lists 24 ga galvanized at .028 in |
| Copper, 16 or 20 oz | Any cut | Fine-tooth hacksaw or cold saw | 16 oz copper is .0216 in thick per the Copper Development Association; heat from a grinder discolors it |
| Vinyl or PVC | Any cut, especially below 50°F | Hacksaw, fine miter blade or PVC cutter | Snips crack cold vinyl walls |
| Any material | The end to slide into an elbow | A 5-blade crimper after the cut | The fresh cut is full size; the crimp makes it the male end |
Downspout stock specs: what you are cutting
| Stock | Profile | Wall thickness | Stick length | Source |
|---|---|---|---|---|
| Englert aluminum downspout | 2×3 in | .019 in (.016 in in Hi Gloss) | 10 ft | Englert product page |
| Lynch Aluminum downspout | 2×3 in | .019 in | 8, 10 or 11 ft by color | Lynch spec sheet |
| Lynch Aluminum downspout | 3×4 in | .019 or .024 in | 8, 10 or 11 ft by color | Lynch spec sheet |
| Berger plain round downspout | Round | Aluminum .019 or .024 in; copper 16 or 20 oz; steel 24 to 30 ga | 10 ft | Berger product catalog |
| 16 oz copper sheet | Any | .0216 in | n/a | Copper in Architecture Handbook |
How do you cut a downspout straight?
Cutting a downspout straight comes down to a square mark and a secured piece, not a steady hand. A downspout that shifts while you cut wanders off the line, and a cut that is off square by even 1/8 in across a 4-inch face leaves a wedge-shaped gap that leaks at the joint. Work through the sequence below in order.
- Measure and add for overlap. Measure the run from the outlet to the elbow or ground target, then add 1 to 2 inches so the cut end can nest into the next section. Downspouts telescope, so the upper piece always goes inside the lower.
- Mark a square line around all sides. Use the paper-wrap method below for a line that stays square, not a single tick you eyeball.
- Clamp it down. Set the downspout in a vise with soft jaws, or clamp it to a workbench next to the line. Unsupported .019-inch aluminum flexes and grabs the blade.
- Cut on the waste side of the line. Keep the blade just outside the mark so the finished length lands exactly on it.
- Go slow at the corners. On a 2×3 or 3×4-inch rectangular downspout, the 4 folded corners are where the blade meets the wall edge-on with the fewest teeth engaged. Cut across each flat face first, then ease the saw or snips through the corners so the profile does not fold inward.
- Deburr and test-fit. File the edge, then slide it into the mating part before you fasten anything.
How to mark a rectangular downspout so the cut stays square
Wrap a sheet of 8.5×11-inch printer paper around the downspout and align the overlapping edge to itself, then trace along the paper edge. Because the paper meets itself evenly, the line it leaves is perpendicular to the length on all four faces. A single pencil tick carried by eye almost always drifts on the back face, which is the one you cannot see while cutting. This one step fixes the most common reason a cut end will not seat flush.
For round downspouts the same paper-wrap trick works and matters even more, since there is no corner to reference. Painter’s tape wrapped once around a 3-inch or 4-inch round pipe is a faster field version: cut along the tape edge and the line stays square.
Crimping the cut end to fit an elbow or the next section
A fresh cut leaves the downspout full-diameter, so it will not slide into an elbow or the section below it. Crimping with a gutter crimping tool pinches the last 1 to 1.5 inches inward so that end nests inside the mating part. The A versus B gutter elbow you are fitting changes how the pieces nest. Always crimp the cut end, and always point the crimped (male) end down, so water runs into the joint rather than out of it. Skipping the crimp is why butt-joined downspouts drip at every seam.
A 5-blade crimper such as the Malco C5R makes a 1-5/8 in long, shallow double crimp in one squeeze, and Malco rates it for aluminum up to .035 in, which covers .019 and .024 in downspout stock. Insert the jaws about 1 inch, hold the tool square to the edge, and work around the perimeter. No crimper on hand? Bend the edges in with needle-nose pliers, working opposite sides in small steps so the end narrows evenly instead of folding flat. Test the fit into the elbow after every few bends.
Which end do you cut, and how far above the elbow to stop
Cut from the bottom of the run and preserve the factory-crimped top end wherever possible, because that end is already sized to receive the outlet or elbow above it. When you must shorten the top, plan to re-crimp it. Leave roughly 1 to 2 inches of straight downspout above each elbow so there is enough material to crimp and still get a full overlap into the elbow throat. At the bottom, cut for the discharge point, not the ground: where expansive or collapsible soils are known to exist, IRC R801.3 requires roof drainage to discharge at least 5 feet from foundation walls or into an approved drainage system, so plan the elbow and extension length before the final cut.
On an offset (the two-elbow jog that carries the downspout from the fascia back to the wall), the short filler piece between the elbows is almost always a field cut. Measure it in place, cut it 1 inch long, crimp one end, then trim again if the offset does not close cleanly. A downspout cut too short at the bottom is a common repair; see our rain gutter repair fixes by problem. For deeper how-to reference, start at our learn about roofing hub.
Deburring and safety
A cut edge on .019 to .024-inch metal carries a sharp burr that will slice a hand and hang up the joint. Run a flat file or medium-grit emery cloth along the inside and outside of the cut, then test the edge with a gloved finger. Wear cut-resistant gloves and safety glasses for every cut: aluminum slivers and steel chips both find skin and eyes. Support the offcut so it does not drop and bounce when the blade breaks through. A clean, square cut also keeps the finished downspout easier to clear of debris later.
Frequently asked questions
What is the best tool to cut a downspout?
For .019 to .024-inch aluminum, aviation snips or a fine-tooth hacksaw give the cleanest cut. For steel, galvanized, or copper, use a hacksaw or a reciprocating saw with a bi-metal metal-cutting blade. Vinyl cuts best with a hacksaw or a PVC pipe cutter. A hacksaw with a 32 TPI blade is the one tool that handles every downspout material acceptably, which makes it the safe default for a single project.
What are downspout snips?
Downspout snips are double-cut snips with 3 blades that remove a thin strip of metal instead of folding it, so the downspout keeps its shape. Malco rates its Max2000 (M2004) for aluminum up to .040 in, and the Midwest MWT-P1 duct cutter removes a 3/16 in strip at up to 1-1/4 in per stroke, per each maker’s spec.
Can you cut a downspout with tin snips?
Yes, on aluminum. Aviation (tin) snips cut 0.019 to 0.032-inch aluminum downspouts quickly and cleanly. Start from the open end and cut around to your line. Snips are a poor choice on steel, galvanized, or copper, where they distort the profile and dull fast, and they can crack vinyl in cold weather. For those materials use a saw instead.
Can you cut a downspout with a hacksaw?
Yes. A hacksaw with a 32 TPI bi-metal blade (one tooth every 1/32 in) cuts aluminum, steel, copper and vinyl downspouts. Clamp the piece, cut across each flat face first, then ease through the 4 corners of a rectangular profile so the blade does not snag and fold the wall.
How do you cut a downspout straight?
Wrap a sheet of paper or a strip of tape around the downspout so the edge meets itself, then trace that edge to get a square line on all sides. Clamp the piece in a vise, cut just on the waste side of the line, and ease through the 4 corners on 2×3 or 3×4-inch rectangular stock. The square mark and the clamp, not a steady hand, are what keep the cut straight.
Which end of the downspout do you crimp?
Crimp the cut end, and orient it downward so it nests inside the elbow or section below it. Crimping pinches the last 1 to 1.5 inches inward so the full-diameter cut can enter the mating part. The male crimped end always points down the flow path so water runs into the joint, not out of it.
Can you cut a vinyl downspout the same way?
Vinyl downspouts cut with a hacksaw, a fine-tooth miter blade, or a PVC pipe cutter, not with snips. Snips crack vinyl walls, especially below about 50 degrees Fahrenheit. Cut slowly, deburr the edge with a file, and note that vinyl sections usually snap or slide together with less crimping than metal because the profiles are molded to nest.
How much downspout should you leave above an elbow?
Leave about 1 to 2 inches of straight downspout above each elbow. That gives you enough material to crimp the cut end and still seat a full overlap into the elbow throat. Too short and the crimp has nothing to grip; too long and the offset will not close against the wall. Measure in place, cut long, then trim to fit.