Rational Method Formula Calculator for Peak Runoff

Want to simplify the process of determining the right culvert size? Use the calculator below to quickly estimate peak discharge (Q) using the Rational Method formula. Just enter the runoff coefficient (C), rainfall intensity (I), and drainage area (A) to get an accurate result. This tool is perfect for contractors looking for a quick and easy way to handle drainage calculations on-site.

Rational Method Calculator







Peak Discharge (Q): cfs

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