Welder Generator Sizing Calculator
Calculate the exact generator size required to run your MIG, TIG, or Stick welder safely. Prevent breaker trips and protect sensitive inverter electronics with accurate power sizing.
Welder Specifications
Modern, highly efficient. Requires ~25% surge overhead.
Recommended Generator Size
Minimum Starting (Peak) Watts required
Ensure your generator provides Clean Power (<5% THD) for inverter welders.
Generator Sizing Guide
Choosing the right generator for your welder is crucial. If the generator is too small, it will trip its breaker when you strike an arc, or worse, it could damage the sensitive electronics in modern inverter welders due to severe voltage drops.
Inverter Welders
Modern, lightweight, and highly efficient. They convert AC to DC and switch it at high frequencies. Because they have a high power factor and low inrush current, you typically only need a generator that provides 1.25x to 1.3x the welder's rated input power.
Transformer Welders
Older, heavy, and rugged machines. They rely on a large magnetic core which requires a massive "inrush" of current to magnetize when striking an arc. You need a generator that provides 1.6x to 2.0x the rated input power to prevent tripping breakers.
Clean Power (THD) Warning
Total Harmonic Distortion (THD) measures the quality of the AC power. Modern inverter welders with digital displays and microprocessors require "clean power" (typically <5% THD). Using a standard construction generator with high THD can fry the circuit boards in an inverter welder. Always look for an Inverter Generator or a standard generator explicitly rated for low THD when running modern welding equipment.