USB Power Delivery Calculator

This tool calculates key electrical and compliance parameters for USB PD 3.1 power profiles, including delivered power (W), required cable current rating, voltage-current compatibility, and whether a given cable type (standard or EPR) supports the selected profile. It also flags potential violations of USB-IF specifications.

Use it during power architecture planning—especially when selecting USB-C power adapters, designing sink devices (e.g., laptops, monitors), or qualifying cables for high-power applications like 48V/5A (240W) charging. It helps avoid over-spec’ing components or violating USB PD 3.1 mandatory handshake requirements.

“PD Profile” is the negotiated output voltage (5–48 V in 1-V steps, though only standardized voltages like 20V/28V/48V are commonly used). “Current Limit” is the maximum current (A) the port or cable must deliver at that voltage. “Cable Type” indicates conductor capability: 1 = standard 3A cable (up to 60W), 2 = EPR (Extended Power Range) rated ≥5A (required for >60W).

Standard PD 3.0 profiles include 5V/3A (15W), 9V/3A (27W), 15V/3A (45W), and 20V/5A (100W). PD 3.1 adds 28V/5A (140W), 36V/5A (180W), and 48V/5A (240W). Current limits range from 1.5A (for legacy cables) to 5A (EPR only); never exceed 5A — higher currents require proprietary solutions outside USB-IF specs.

USB-IF mandates Extended Power Range (EPR) cables for any profile delivering >60W (i.e., >20V×3A or >5A at any voltage). Standard USB-C cables are certified only up to 3A/60W; using them beyond that risks overheating, voltage drop, or handshake failure. The calculator enforces this compliance rule automatically.

No—it assumes compliant negotiation and calculates *what’s possible* given your inputs. Actual device support depends on firmware, controller IC capabilities (e.g., support for PPS, variable voltage, or EPR messaging), and physical layer robustness. Use this tool alongside your controller’s datasheet and USB-IF certification test plans.

This calculator does not model voltage drop or thermal derating due to cable resistance—but it implies compliance by requiring EPR cables above 60W, which are tested for lower resistance (<0.05Ω per contact pair) and enhanced thermal management. For precision designs, always validate with worst-case IR-drop analysis and temperature rise testing.

The calculator will still compute power (144W), but the result table explicitly warns “EPR cable required” and highlights non-compliance. USB PD 3.1 controllers would reject such a request during negotiation unless both source and sink explicitly support EPR mode and the cable reports proper EPR certification via SOP′ messages.

No—this calculator focuses on fixed-voltage PD profiles defined in USB PD 3.1. PPS enables fine-grained voltage/current control (e.g., 3.3–21V in 20mV steps) and requires separate negotiation logic. While PPS can improve efficiency, its implementation isn’t reflected in the fixed-profile power calculations shown here.

This tool doesn’t specify AWG directly, but EPR cables (Type 2 input) are typically built with ≥20 AWG conductors for VBUS and ground, plus active electronics for certification. For custom cables, refer to USB-IF Cable Certification Specifications and perform ampacity + thermal modeling—especially for sustained 5A loads at 48V where power dissipation becomes critical.