Cutting Guide
Plasma vs Laser vs Waterjet Cutting
Three ways to cut a metal sheet, each with a different trade-off between speed, cost, accuracy and the materials they can handle. Here's how to pick.
Every metal cutting job balances the same three things: how fast it cuts, how much it costs to run, and how good the finished edge needs to be. Plasma, laser and waterjet each sit in a different spot on that trade-off, and the right choice usually comes down to material, thickness, and what happens to the part after it's cut.
Cost out all three for your job
Run the same part through the laser, plasma and waterjet cost calculators to compare directly.
Speed
Plasma is the fastest of the three on mild steel, especially at thickness above 6mm, because it cuts by melting the material with an ionised gas jet. Laser is close behind on thinner material and pulls ahead on precision, but slows down more steeply as thickness increases. Waterjet is the slowest by a clear margin on metal, since it erodes material with an abrasive-laden water stream rather than melting it — but its speed barely changes with material type, which the thermal processes can't say.
All three roughly follow the same rule: doubling the thickness roughly halves the speed. Use the laser, plasma and waterjet cost calculators for a speed estimate at your own thickness and material.
Cost
Plasma machines and consumables are the cheapest to buy and run, which combined with its speed on thick steel usually makes it the lowest cost-per-part for structural and heavier fabrication work. Laser costs more per hour to run but its precision reduces secondary finishing, which can offset the higher machine rate on parts with tight tolerances. Waterjet has the highest running cost per hour of the three — abrasive consumable use adds up — and its lower speed compounds that on longer cut paths.
Accuracy and edge quality
Waterjet leaves the cleanest edge of the three, with no heat-affected zone, no discolouration and minimal distortion, which matters on parts that get welded, painted or need a tight tolerance fit. Laser gives a very good edge on thinner material with a small heat-affected zone. Plasma has the largest heat-affected zone and roughest edge of the three, though modern precision plasma systems have closed much of that gap versus older equipment.
Material range
Waterjet cuts almost anything — metal, stone, glass, composites, rubber — since it doesn't rely on melting or burning the material. Laser and plasma are both effectively limited to conductive or absorptive materials; laser struggles with highly reflective metals like polished aluminium and copper at lower power, while plasma cuts any conductive metal well regardless of reflectivity.
Which should you use?
As a rough starting point: choose plasma for thicker mild steel structural and general fabrication work where cost and speed matter most; choose laser for thinner material, tighter tolerances and cleaner edges at moderate cost; choose waterjet when the material can't take heat, when edge quality is critical, or when cutting non-metals alongside metal parts.
Frequently asked questions
Which is cheaper, plasma or laser cutting?
Plasma machines and consumables are usually cheaper, and plasma cuts thick mild steel faster, so per-part cost on thick steel often favours plasma. Laser tends to win on thinner material and precision parts where less rework offsets the higher machine cost.
Is waterjet cutting slower than plasma or laser?
Yes — waterjet is typically the slowest of the three on metal, often around a third of plasma's speed on comparable mild steel thickness, because it removes material by abrasive erosion rather than melting or vaporising it.
Which cutting process gives the best edge quality?
Waterjet generally gives the cleanest edge with no heat-affected zone, laser gives a very good edge on thinner material, and plasma gives the roughest edge with the largest heat-affected zone.