The quickest way to cut rebar on most jobs is an angle grinder with a metal cutoff wheel for a few bars, or a dedicated rebar cutter (manual for small bars, electric or hydraulic for larger ones) when you have many cuts to make. A metal-cutting chop saw, a reciprocating saw or an oxy-fuel torch also work, and the right choice comes down to bar size, how many cuts, whether you have power, and whether the bar is coated.
This guide compares each method, walks through a clean grinder cut step by step, and covers coated bars, cutting bars already in concrete, and the safety rule that applies to every cut end left sticking up.
Before You Cut: Know the Bar
Rebar in the US is named by size number, which is its nominal diameter in eighths of an inch for bars up to #8. A #4 bar is 0.500 in, a #5 is 0.625 in and a #6 is 0.750 in. Our rebar sizes chart lists every size from #3 to #18 with diameter, area and weight per foot. Bigger bars take longer to cut and need a heavier tool.
Check the rolled-in markings before cutting too. Per CRSI’s guide to bar identification (checked November 2026), each bar carries a mill mark, the size, a type letter (“S” for carbon steel to ASTM A615 or “W” for low-alloy weldable steel to ASTM A706) and a grade mark. Higher-grade bars are harder and wear blades faster, and knowing the grade matters if anyone later wants to weld or bend the cut piece. For what the grade numbers mean in strength terms, see yield strength of steel.
Ways to Cut Rebar Compared
| Method | Best for | Pros | Cons |
|---|---|---|---|
| Angle grinder with metal cutoff wheel | A few cuts on any common size, cuts in place | Cheap, portable, cuts at any angle | Sparks, heat, slower on large bars; wheel can shatter if pinched |
| Manual rebar cutter / bolt cutter style | Small bars (#3, #4) in volume | No power, no sparks, fast | Hard work; each tool is rated for a maximum bar size and grade |
| Portable electric or hydraulic rebar cutter | Many cuts on #3 to #8 and up | Fast, square, no sparks, low effort | Expensive to buy; rent for one-off jobs |
| Metal-cutting chop saw | Repeat cuts to the same length at a bench | Square, consistent lengths with a stop | Not portable to the pour; abrasive types throw sparks |
| Reciprocating saw with metal blade | Awkward spots, cutting bars sticking out of old concrete | Reaches tight places, few sparks | Slow on larger bars, eats blades |
| Oxy-fuel torch | Large bars and demolition | Cuts heavy bars quickly | Fire risk, heat-affected ends, burns coatings; needs training |
Whatever the tool, check its rated capacity against the bar size and grade before you start. A cutter forced past its rating can break, and a grinder wheel used past its speed rating can burst.
How to Cut Rebar With an Angle Grinder
An angle grinder is the tool most people already own, so here is the process in order.
- Gear up. Safety glasses under a face shield, hearing protection, leather gloves and long sleeves. Clear anything flammable from the spark path.
- Fit the right wheel. Use a thin metal cutoff wheel rated for the grinder’s speed, with the guard on and positioned between you and the wheel.
- Measure and mark. Measure from a square end and mark the cut with a paint marker or soapstone all the way around the bar.
- Support both sides. Clamp the bar or rest it so the cut opens as you go. If the offcut sags and closes on the wheel, it can pinch and kick back.
- Cut steadily. Let the wheel’s speed do the work with light pressure, keep the wheel in one plane and do not twist it in the kerf.
- Dress the end. Knock off the burr with a flap disc if the end will be handled or slid through a sleeve.
Tips for cleaner, faster cuts
- Cut bars in a bundle only with a tool built for it; single bars with a grinder are safer.
- Cut lengths a little long if the exact length is not critical; you can trim, you cannot add.
- For dozens of identical bars, set a stop block on a bench and use a chop saw or rebar cutter.
- Let hot ends cool before handling, especially after a torch cut.
Cutting Epoxy-Coated and Galvanized Rebar
Coated bars are used where corrosion is a concern, such as bridge decks, parking structures and marine work. A cut exposes bare steel at the end, so project specifications for coated bars normally require the cut ends to be touched up with a compatible patching material before the bar is placed. Shear-type cutters and saws are kinder to coatings than torches, which burn the coating back from the cut. Check the project specification for the approved repair product and method.
Cutting Rebar That Is Already in Concrete
Trimming dowels left too long above a slab or footing is routine, and a grinder or reciprocating saw is the usual tool. Cutting bars inside a slab, beam, column or wall is different. Those bars carry tension, and cutting them, for example to core a hole or fit a pipe, can weaken the member. Scan before coring, and have a licensed structural engineer approve any cut through structural reinforcement.
The same applies to bars connecting new work to old, such as the dowels at a pier and beam foundation or the embedded steel around anchor bolts. If a bar looks in the way, ask before cutting it.
Guard Every Cut End: Impalement Protection
Cutting rebar to length often leaves vertical bars sticking up out of footings and walls, and those ends are a serious impalement hazard. OSHA’s concrete rule, 29 CFR 1926.701(b) (checked November 2026), requires that all protruding reinforcing steel onto and into which employees could fall be guarded to eliminate the hazard of impalement.
CRSI’s impalement safety guidance (checked November 2026) recommends approved caps or wooden troughs over exposed ends, and states that bending bars into 90-degree hooks or 180-degree “candy canes” is not adequate impalement protection on its own. It also points out that where people work above exposed rebar, fall protection is the first line of defense. Plain plastic mushroom caps keep scratches down but are not all rated for impalement, so check the cap’s rating against the fall height.
Can You Bend Rebar After Cutting It?
Yes, with a rebar bender sized for the bar, and many portable tools combine a cutter and a bender. Bend cold, to the bend diameter shown on the drawings, and do not heat bars to bend them unless the engineer of record approves it. Heat can change the steel’s properties, and re-straightening bars that are already partly embedded in concrete is also something the engineer must approve.
How to Cut Rebar FAQ
Can you cut rebar with bolt cutters?
Large bolt cutters can cut small bars, typically #3 and sometimes #4, but they take a lot of effort and the jaws can be damaged. A manual rebar cutter is built for the job and lists the bar sizes and grade it can handle.
What is the best blade for cutting rebar?
For a grinder, a thin metal cutoff wheel. For a circular or chop saw, a blade made for cutting steel, either abrasive or carbide-tipped, rated for the saw’s speed. For a reciprocating saw, a bi-metal or carbide metal-cutting blade.
Can you cut rebar with a hacksaw?
Yes, for one or two small bars, but it is slow. Any powered method is faster once you have more than a couple of cuts.
Is it OK to torch cut rebar?
Torch cutting is common for large bars and demolition, but it heats the end and burns coatings. Check the project specification, since some jobs restrict flame cutting for bars that will be welded or that carry coatings.
Do I need to cap rebar after cutting?
On any job where someone could fall onto the ends, yes. OSHA requires protruding bars to be guarded against impalement, using rated caps, troughs or another method that removes the hazard.
Reference information only, not engineering advice. Disclaimer.