Duty Cycle Estimator

Calculate your welder's safe arc-on time and required rest time when operating at an amperage different from its rated spec.

Machine Nameplate Rating
A
%
Amps
The amperage you actually plan to weld at for this job.
Operating Limits
Calculated Duty Cycle

Welder Duty Cycle Estimator

%
Safe Arc-On Time

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Maximum continuous weld
Required Cool Down

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Minimum rest before restarting
What is Duty Cycle?

Duty cycle is the percentage of a given time period (usually 10 minutes) that a welding machine can safely operate at a specific output current without overheating its internal components.

The Inverse Square Law
$DC_{new} = DC_{rated} \times \left(\frac{Amps_{rated}}{Amps_{new}}\right)^2$
Because heat generation ($I^2R$ loss) scales with the square of the current, increasing your amperage reduces your duty cycle exponentially, not linearly.
Example (NEMA 10-Min Standard)
  • Machine Rating: 200A @ 60% Duty Cycle
  • Meaning: At 200 Amps, you can weld continuously for 6 minutes, but you MUST let the machine idle and cool for 4 minutes.
  • If turned up to 250A: The new duty cycle drops to ~38% (3.8 minutes welding, 6.2 minutes cooling).
Hard Limit Warning: While you can mathematically calculate the duty cycle for any amperage, you must never exceed the absolute maximum output rating of the machine.