Welding: Duty-Cycle Weld Time

Excel Formulas › Welding & Fabrication

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A welder's duty cycle is the share of a ten-minute block it can run at a given amperage before it needs to cool. Turn that percentage into minutes and you know how long you can weld before the machine forces a break.

Quick formula: Duty-cycle percent of a ten-minute block:

=B2/100*10

A 60% duty cycle means six minutes of welding, then four to cool, in every ten-minute stretch.

The example

Three machines, each with a rated duty cycle at the amperage in use.

	A	B	C
1	Machine	Duty %	Weld min
2	MIG 210	60	6
3	Stick 160	40	4
4	TIG 200	20	2

The formula

Duty cycle is a percent of ten minutes, so convert and multiply:

=B2/100*10 // duty-cycle percent of a 10-minute period, in minutes

How it works

Two small steps:

B2/100 converts the duty-cycle percentage to a fraction.
*10 applies it to the standard ten-minute rating period to get weldable minutes.
The rest of the ten minutes is forced cool-down — ten minus the weld time.
Duty cycle is quoted at a specific amperage; drop the amps and the duty cycle rises, weld longer at lower current.

Exceeding the duty cycle trips the thermal cutout and can damage the machine — size the welder so its duty cycle covers your longest continuous bead.

Try it: interactive demo

Interactive

Enter the machine's duty-cycle percentage at your working amperage.

Duty cycle (%)

Variations

Cool-down minutes

The remainder of the ten-minute block is forced rest.

=10-B2/100*10

Weld time over an hour

Six ten-minute blocks in an hour of arc-on time.

=B2/100*10*6

Pitfalls & errors

Duty cycle is tied to a stated amperage. A machine rated 60% at 200A may be 100% at 120A — always read the rating for the current you actually run.

The ten-minute period is the industry standard, but a few machines are rated over five minutes. Check the spec plate before assuming ten.

Practice workbook

📊

Download the free Welding: Duty-Cycle Weld Time practice workbook

Edit the yellow duty-cycle cells; the weldable minutes recalculate.

Frequently asked questions

What is a duty cycle?

It is the percentage of a ten-minute period a welder can run at a given amperage without overheating. A 60% duty cycle means six minutes welding and four minutes cooling in every ten.

How do I weld longer?

Run at a lower amperage — duty cycle rises as current drops — or buy a machine with a higher duty cycle at your working amps. Pushing past the rating trips the thermal protection.

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