Where the money actually goes
Run the numbers on almost any real job and the ranking comes out the same. Labor and machine time first, usually by a wide margin. Consumables second. Gas third, and often close to nothing if you are cutting with shop air. Electricity last, and small enough that people who obsess over it are optimising the wrong end of the problem.
That ranking is the reason this page asks for an operating factor. Arc-on time is not the time you pay for. A machine that cuts for twenty minutes in an hour has an operating factor of about 33 percent, and every dollar of hourly rate lands on the job at three times the rate the arc time suggests. Loading, unloading, programming, unbolting a jammed slat and fetching a new sheet all happen on the clock.
Consumables are consumed per pierce, not per foot
This is the single most useful thing to internalise about plasma. Steady-state cutting is relatively gentle on a nozzle and electrode. Piercing is not: the arc has to blow through the plate from a standstill, the molten metal comes back up at the shield, and each pierce takes a measurable bite out of the consumable life. Manufacturers rate consumables in pierces for exactly this reason, and a job made of many small holes will eat a set of consumables in a fraction of the linear footage that a job made of long profiles would.
What follows from that is a nesting instruction rather than a purchasing one. Chain cuts so one pierce serves several features. Lead in from the edge of the plate where the geometry allows, which costs no pierce at all. Drill the small holes rather than piercing them if a drill is available. On thick plate, none of this is marginal: pierce time alone can exceed cutting time, and the calculator flags it when that happens.
Cut speed is a chart figure and a real figure
The speed field wants a number from the cut chart for your torch, your amperage and your thickness, and those charts are honest, but they describe a clean cut on flat clean plate with fresh consumables at the correct height. Rusty or painted material, worn consumables, a wandering torch height and a machine that decelerates hard on every corner all pull the real average below the chart. A part with a lot of small features never achieves its chart speed anywhere.
If you are costing an existing job rather than quoting a new one, take the average from the machine. Total cut length divided by observed arc time is a better input than anything from a chart, and it already includes all the deceleration you cannot easily model.
Hazards this page does not manage
Thermal cutting and welding produce fume that is a respiratory hazard, and galvanized coating produces especially harmful fume when it is burnt off. The arc from plasma and from welding burns eyes and skin with ultraviolet, including reflected light and including bystanders who are not looking at it. Cutting and grinding throw sparks that can start a fire hours after the work has stopped and everyone has gone home. Handling all three properly is a matter of ventilation, training and a written procedure for your shop, and none of it is something a calculator or a web page can specify for you.
Related to that: this page and the others in this section estimate consumables, machine settings and cost. They do not assess structural adequacy. Sizing a weld that carries load, or any attachment used for lifting, is work for a qualified engineer and a certified welder to a written procedure, and no figure produced here substitutes for that.
Costing the rest of the job
The cut is one line on the invoice. The plate itself is usually a larger one, and the metal weight calculator prices it from your own dollars per pound. If the parts are folded after cutting, the press brake tonnage calculator tells you whether the machine can form them and the bend allowance calculator gives the flat pattern that has to be cut in the first place. If they are welded, the weld cost calculator covers filler, gas and arc time per joint. Working out which gauge of material you are even quoting is the sheet metal gauge chart.
Questions people ask
What does plasma cutting cost per foot?
For thin mild steel on a well-nested job with shop air, the consumable and gas cost alone is often in the region of twenty to fifty cents a foot, and the number climbs steeply with thickness because the cut slows down and the pierces get harder. Adding labor at any realistic shop rate usually doubles or triples it. Anyone quoting you a single cost-per-foot figure without asking about thickness, pierce count and what your hourly rate is has not costed anything, they have quoted an average of jobs that are not yours. Put your own consumable price and life into the fields above and the answer will at least be about your shop.
How long do plasma consumables last?
The manufacturer rates them in pierces for a given amperage and thickness, and that rating assumes correct pierce height, correct gas pressure and cutting within the machine's rated capacity. Cutting at the top of the thickness range shortens life sharply; so does piercing material thicker than the torch is rated to pierce, which many operators do occasionally and then wonder where the nozzle went. Enter both the pierce rating and, if you have it, the arc hour rating: the calculator charges whichever limit you hit first, which for long-profile work is often the hours and for hole-heavy work is always the pierces.
Is oxy-fuel cheaper than plasma?
On thick carbon steel, often yes for the consumables and the equipment, and it has no electrical cost at all for the cut itself. Against that, oxy-fuel needs a preheat before every pierce that can run twenty seconds or more on heavy plate, cuts slower, leaves a wider kerf and more heat-affected zone, and cannot touch stainless or aluminum in the ordinary way. On thin material plasma wins on every axis. The way to answer it for your job is to run this page twice with the two sets of speeds, pierce times and consumable figures, rather than trusting a general claim in either direction.
Why is my gas cost coming out at zero?
Because the default main gas price is zero, which is correct if you are cutting with shop compressed air from a compressor you already run. If you want to account for that air properly, the honest approach is to work out what the compressor costs to run per hour in electricity and enter it as part of the machine power draw rather than as a gas price. For bottled gas, take the refill price and divide by the cylinder capacity in cubic feet to get a price per cubic foot, and remember you never get the last of it out of the bottle.
Should I include the cost of scrapped parts?
This page does not model scrap, and on a job with any real complexity that omission matters. A first-off that comes out wrong costs the full material, the full cut and the full labor, and it lands on the remaining good parts. If your process reliably produces a percentage of scrap, the simple correction is to divide the total here by the number of good parts rather than the number cut. If you are quoting a new part with unfamiliar geometry, cost at least one throwaway into the first batch and be pleasantly surprised rather than the other way round.