Balancing Valve Sizing Calculator

Determine the recommended pipe/valve size for a circuit balancing valve (e.g. Bell & Gossett Circuit Setter) based on the branch or circuit flow rate.

Circuit / branch flow rate (GPM) Flow through this specific balancing valve

Piping material Affects internal diameter

Maximum design velocity (ft/sec) 4-6 ft/s typical for balancing valves

Enter valid numbers for all fields.

Recommended balancing valve size

Required minimum pipe area

Actual velocity at recommended size

recommended valve pipe size

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This tool recommends a pipe/valve size based on flow velocity only. It does not calculate the exact dial or turn setting needed to achieve your target GPM — that setting is specific to each manufacturer's valve model and must be read from that model's published Cv or flow-setting chart (for example, the Bell & Gossett Circuit Setter Plus setting chart for the size selected here). Use this calculator to confirm the correct valve size, then consult the manufacturer's chart for the exact setting.