Connector Derating Calculator
Enter a connector’s rated current, the reference ambient it was tested at, its max rated temperature, and your actual operating ambient — this estimates how much current the connector can safely carry at your real-world temperature.
Enter values to estimate derated current.
Based on the standard square-root derating approximation (Iderated = Irated × √[(Tmax − Tambient) / (Tmax − Tref)]), the same relationship most manufacturer derating curves are built on. For general engineering reference only — verify against the manufacturer’s published derating curve for your specific part number before finalizing a design.
How this calculator works
Connector current ratings are almost always measured at a specific reference ambient temperature (often 20–30°C) and a specific allowable temperature rise. As ambient temperature climbs toward the connector’s max rated temperature, less of that thermal headroom is left for the heat generated by current flow, so the safe current has to drop. Because resistive heating scales with the square of current, most manufacturer derating curves — and this calculator — use a square-root relationship between remaining temperature headroom and derated current.
For the full explanation of how to read a manufacturer’s actual derating curve, common mistakes, and a worked example, see How to Read Connector Thermal Derating Curves and Cable Temperature Ratings, Current Derating & Voltage Drop. (Double-check both slugs against Strapi before publishing — verify from the live site rather than assuming.)