Power engineering · Calculation tool

ATX 3.x PSU Continuous Load & Excursion Calculator

Separate steady-state PSU loading from short-duration power excursions and compare them with Intel ATX Version 3 design-guide excursion levels.

Continuous load (%) = estimated continuous DC system load ÷ PSU rated output × 100. Excursion load (%) = peak DC load ÷ PSU rated output × 100. The ATX 3 guide defines duration-specific test excursions; these are not extra continuous watts.

Common symptom presets

Presets are illustrative starting points. Review all values against your actual hardware.

Inputs

Estimate

Enter values, then calculate.

Results are theoretical calculations and do not guarantee compatibility, stability, electrical safety, or manufacturer compliance.

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Reference notes

100 µs200% comparison level for qualifying PSU profile
1 ms180% comparison level for qualifying PSU profile
10 ms / 100 ms160% / 120% comparison levels for qualifying PSU profile

Technical sources

This page is an educational estimate. Use current manufacturer datasheets and the complete applicable standard for design sign-off.