Enter your heat load and loop details. The calculator returns the required flow rate, an estimated loop pressure drop (Darcy–Weisbach + fittings), and the pump shaft and electrical power — the numbers you need to pick a pump and sanity-check a CDU design. Coolant properties are nominal near 25 °C.
The free guide walks the whole sizing process — picking ΔT, estimating pressure drop, and reading a pump curve — with this calculator's worked example: How to size a coolant pump for a liquid-cooling loop. The paid Liquid-Cooling Design Kit adds the spreadsheet pack, parallel-branch balancing, and pump-curve matching worksheets.