Duct Size Calculator β Equal Friction Method (Free Tool)
Portlandia Electric Supply Β· Free contractor tools β no signup
π§ Duct Size Calculator β Equal Friction Method
Enter your airflow and get the exact round and rectangular duct sizes from the chart below β no ductulator wheel required.
π§° What you'd need
- Duct run β rigid metal or flex duct in your calculated size β HVAC systems & duct equipment
- Fittings β elbows, take-offs, reducers & register boots β HVAC & air conditioning parts
Sizes follow the equal-friction method at your selected friction rate, matched to the charts in this guide (ACCA Manual D baseline). Rectangular options are the standard equivalents from the round-to-rectangular table below. Always verify total system static pressure against your blower's rated capacity.
π Read the full guide: HVAC Duct Sizing Chart: Complete CFM Guide β charts, code references, and worked examples.
π§° More free tools β β sizing, conversion, and payback calculators, all free.
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