BIZOMAT MAKEOS · Fabrication
Weldment Cost Estimate (Weld Metal, Arc Time, Labour, Filler and Gas by Run)
For a fabrication with several fillet welds of different sizes and lengths, how much weld metal, arc time and cost does it take, and does it fit my quoted price?
Cost estimate of all the fillet welds on a weldment: for each weld run the weld metal per metre from the leg size and excess, then arc time from the deposition rate, paid time from the operating factor, and labour, filler and shielding gas costs (as the weld cost tool, run by run), summed with any fit-up and handling time, against the price you have quoted for the welding.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Number of weld runs | runs | How many different weld runs (sizes) to include. |
| Weld run 1 | ||
| Fillet leg | mm | Fillet leg size of weld run 1. |
| Total length | m | Total length of weld run 1 on the weldment. |
| Weld run 2 | ||
| Fillet leg | mm | Fillet leg size of weld run 2. |
| Total length | m | Total length of weld run 2. |
| Weld run 3 | ||
| Fillet leg | mm | Fillet leg size of weld run 3. |
| Total length | m | Total length of weld run 3. |
| Weld run 4 | ||
| Fillet leg | mm | Fillet leg size of weld run 4. |
| Total length | m | Total length of weld run 4. |
| Process and rates | ||
| Excess weld metal (convexity, spatter) | % | Allowance for convexity and spatter over the plain triangle. |
| Weld metal density | g/cm³ | Density of the weld metal (7.85 for steel). |
| Deposition rate | kg/h | Weld metal deposited per hour of arc time. |
| Operating factor (arc-on share of paid time) | % | Share of paid time the arc is on. |
| Filler deposition efficiency | % | Share of the filler bought that ends up in the weld. |
| Labour and overhead rate | $/h | Labour and overhead per paid hour. |
| Filler price | $/kg | Price of filler wire or rod. |
| Shielding gas flow | L/min | Shielding gas flow while the arc is on (0 for self-shielded processes). |
| Gas price | $/m³ | Price of shielding gas. |
| Fit-up and handling time | h | Time for fit-up, tacking, turning and handling, charged at the labour rate. |
| Price quoted for the welding | $ | The price allowed for the welding. |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Number of weld runs
- What it is
- How many separate fillet weld sizes the weldment has. Each run is one leg size with its total length; runs beyond this count are ignored even if they hold values.
- Units and format
- Enter a number in runs: runs. The form accepts 1 runs to 4 runs. Use a whole number. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 3 runs as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Group all welds of the same leg size into one run and add their lengths together.
Weld run 1
What this means: Fillet leg
- What it is
- The leg size of the first group of fillet welds: the length of each side of the weld triangle measured along the joined faces.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 50 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 6 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Weld metal, arc time and cost per metre all rise with the square of the leg.
- Get it right
- Use leg length, not throat thickness; the throat of an equal-leg fillet is smaller than the leg.
What this means: Total length
- What it is
- The total length of all welds of the first leg size on the weldment, adding every separate weld of that size.
- Units and format
- Enter a number in m: metres. The form accepts 0 m to 10000 m. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 2.4 m as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Every cost of this run rises in direct proportion to its length.
- Get it right
- Enter the length in metres; a weld measured as 600 mm is 0.6 m.
Weld run 2
What this means: Fillet leg
- What it is
- The leg size of the second group of fillet welds: the length of each side of the weld triangle measured along the joined faces.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 50 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 8 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Weld metal, arc time and cost per metre all rise with the square of the leg.
- Get it right
- Use leg length, not throat thickness; the throat of an equal-leg fillet is smaller than the leg.
What this means: Total length
- What it is
- The total length of all welds of the second leg size on the weldment, adding every separate weld of that size.
- Units and format
- Enter a number in m: metres. The form accepts 0 m to 10000 m. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1.2 m as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Every cost of this run rises in direct proportion to its length.
- Get it right
- Enter the length in metres; a weld measured as 600 mm is 0.6 m.
Weld run 3
What this means: Fillet leg
- What it is
- The leg size of the third group of fillet welds: the length of each side of the weld triangle measured along the joined faces.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 50 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 5 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Weld metal, arc time and cost per metre all rise with the square of the leg.
- Get it right
- Use leg length, not throat thickness; the throat of an equal-leg fillet is smaller than the leg.
What this means: Total length
- What it is
- The total length of all welds of the third leg size on the weldment, adding every separate weld of that size.
- Units and format
- Enter a number in m: metres. The form accepts 0 m to 10000 m. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 3 m as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Every cost of this run rises in direct proportion to its length.
- Get it right
- Enter the length in metres; a weld measured as 600 mm is 0.6 m.
Weld run 4
What this means: Fillet leg
- What it is
- The leg size of the fourth group of fillet welds: the length of each side of the weld triangle measured along the joined faces.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 50 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 10 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Weld metal, arc time and cost per metre all rise with the square of the leg.
- Get it right
- Use leg length, not throat thickness; the throat of an equal-leg fillet is smaller than the leg.
What this means: Total length
- What it is
- The total length of all welds of the fourth leg size on the weldment, adding every separate weld of that size.
- Units and format
- Enter a number in m: metres. The form accepts 0 m to 10000 m. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 0.5 m as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Every cost of this run rises in direct proportion to its length.
- Get it right
- Enter the length in metres; a weld measured as 600 mm is 0.6 m.
Process and rates
What this means: Excess weld metal (convexity, spatter)
- What it is
- Extra weld metal over the plain triangular fillet section, allowing for a convex face, reinforcement and spatter. It is added to the theoretical weld metal of every run.
- Units and format
- Enter a number in %: percent: the number is read as a percentage, so type 8 for 8 %. The form accepts 0% to 100%. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 15% as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Weld metal, arc time, labour, filler and gas all rise in proportion to one plus this share.
- Get it right
- Type the percentage itself, not a fraction; it is a share of the plain triangular section.
What this means: Weld metal density
- What it is
- The density of the deposited weld metal, used to turn the weld cross-section into a mass per metre. Take it from the filler supplier or the parent metal data.
- Units and format
- Enter a number in g/cm³: grams per cubic centimetre (1 g/cm³ = 1000 kg/m³). The form accepts 0.000001 g/cm³ to 25 g/cm³. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 7.85 g/cm³ as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Weld metal mass, and so every time and cost, rises in proportion to density.
- Get it right
- Enter it in g/cm³; a value in kg/m³ must be divided by 1000.
What this means: Deposition rate
- What it is
- The mass of weld metal the process lays down per hour while the arc is actually burning, from the process or consumable supplier for your wire size and settings.
- Units and format
- Enter a number in kg/h: kg/h. The form accepts 0.000001 kg/h to 50 kg/h. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 3 kg/h as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A higher deposition rate cuts arc time, paid time, labour and gas cost in inverse proportion.
- Get it right
- Use the deposition rate for arc-on time, not an output per shift that already includes stoppages; stoppages are covered by the operating factor.
What this means: Operating factor (arc-on share of paid time)
- What it is
- The share of the welder’s paid time during which the arc is on; the rest goes on changing wire, chipping, repositioning and similar tasks. Arc time is divided by it to get paid welding time.
- Units and format
- Enter a number in %: percent: the number is read as a percentage, so type 8 for 8 %. The form accepts 1% to 100%. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 30% as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A lower operating factor raises paid welding time and labour cost in inverse proportion.
- Get it right
- Type the percentage itself. Fit-up and handling time is entered separately below, so do not allow for it twice here.
What this means: Filler deposition efficiency
- What it is
- The share of the filler wire or rod you buy that ends up in the weld, after losses to spatter, stub ends and slag. The weld metal mass is divided by it to get the filler purchased.
- Units and format
- Enter a number in %: percent: the number is read as a percentage, so type 8 for 8 %. The form accepts 1% to 100%. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 92% as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A lower efficiency raises filler cost only; labour and gas are not affected.
- Get it right
- Type the percentage itself. Take the figure for your process and consumable from the supplier.
What this means: Labour and overhead rate
- What it is
- The cost of one paid hour of welding labour including overheads, as charged by your organisation. It is applied to paid welding time and to fit-up and handling time.
- Units and format
- Enter a number in $/h: money per hour. The form accepts $0/h to $10000/h. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with $95/h as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Labour and fit-up cost rise in direct proportion to the rate.
- Get it right
- Use the fully burdened rate your finance team uses for quoting, not the welder’s wage alone.
What this means: Filler price
- What it is
- The price you pay per kilogram of filler wire, rod or electrode, from your supplier invoice or quotation.
- Units and format
- Enter a number in $/kg: money per kilogram. The form accepts $0/kg to $1000/kg. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with $6/kg as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Filler cost rises in direct proportion to the price.
- Get it right
- Use the price per kilogram, not per spool or per packet.
What this means: Shielding gas flow
- What it is
- The flow of shielding gas through the torch while the arc is on, read from the flowmeter or the welding procedure. Gas used is this flow times arc time.
- Units and format
- Enter a number in L/min: litres per minute. The form accepts 0 L/min to 100 L/min. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 15 L/min as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Gas cost rises in direct proportion to the flow.
- Get it right
- Use 0 for self-shielded or flux processes with no gas. Gas used between welds is not counted.
What this means: Gas price
- What it is
- The cost of one cubic metre of shielding gas as delivered, from your gas supplier, including any cylinder rental you want to recover.
- Units and format
- Enter a number in $/m³: money per m³. The form accepts $0/m³ to $1000/m³. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with $12/m³ as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Gas cost rises in direct proportion to the price.
- Get it right
- Gas is often priced per cylinder; divide the cylinder price by its contents in cubic metres.
What this means: Fit-up and handling time
- What it is
- The paid time for the whole weldment spent on fit-up, tacking, turning, cleaning and handling, outside the weld runs themselves. It is charged at the labour rate.
- Units and format
- Enter a number in h: hours. The form accepts 0 h to 10000 h. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1.5 h as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Each hour adds one hour of the labour rate to the total.
- Get it right
- Enter it in hours for the whole weldment; 45 minutes is 0.75 h.
What this means: Price quoted for the welding
- What it is
- The price you have quoted or been allowed for the welding work on this weldment. The estimated total cost is compared with it.
- Units and format
- Enter a number in $: an amount of money; use one currency for every money input. The form accepts $0 or more. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with $300 as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Compare like with like: if the quote also covers material or finishing, use only the welding share.
Method and formulas
- Weld metal per metre = ½ leg² × (1 + excess) × density; arc time = mass ÷ deposition rate; paid time = arc time ÷ operating factor (as the weld cost tool).
- Labour = paid time × rate; filler = mass ÷ efficiency × price; gas = arc minutes × flow × gas price.
- Each run multiplied by its length; fit-up time at the labour rate added.
- Example: 1.0752 kg of weld metal, 2.6946 h paid including fit-up, $267 in all.
Limitations
- Fillet welds only; groove welds have a different cross-section.
- Deposition rate and operating factor vary widely with process, position and shop.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Price the welding on a frame or bracket
- Compare leg sizes on cost
- Check a welding quote
Who it is for
- Estimators
- Fabrication engineers
- Welding supervisors
What you get
- Weld metal, arc and paid time by run
- Labour, filler and gas cost
- Total against the quote
Interpreting the result
- Weld metal grows with the square of the leg: one size up on a long run usually costs more than all the short runs.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1438–1441. Topic reference; no source tables or recommended settings are reproduced.
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Open the Weldment Cost Estimate (Weld Metal, Arc Time, Labour, Filler and Gas by Run) calculator