The Optional Method (NEC 220.82) is usually simpler and yields a lower calculated load for a typical single dwelling on a 100A+ service: 100% of the first 10 kVA of general loads + 40% of the remainder, then the largest HVAC load. The Standard Method (Article 220 Part III) applies specific demand factors line-by-line and is required in some situations. When in doubt, run both.
CircuitCalcPro is a decision-support tool. Results are estimates based on your inputs. Verify against the adopted code edition and your local AHJ before use. Auto-filled property data comes from public sources and must be verified.
Calculations use NEC 2023 (3 VA/ft² general lighting). NEC 2026 is not available yet. Table 220.55 beyond 8 ranges is approximate.