Visual Calculators
Use practical water, stormwater, drainage, pump, BMP, and unit conversion calculators for planning-level checks and learning. The next generation of these tools will combine numeric results with live diagrams, charts, and editable inputs.
New: Visual Water Engineering Calculators
Try the first interactive visual calculator and see how this section will evolve from static calculators into live engineering tools.
Rainwater Harvesting CalculatorEstimate roof runoff collection, usable storage, and overflow.
Manning Equation CalculatorCalculate open channel and pipe flow properties.
Pipe Capacity CalculatorEstimate full-flow circular pipe capacity with Manning equation.
Detention Storage CalculatorEstimate planning-level detention storage based on inflow and allowable release.
Orifice and Weir CalculatorEstimate discharge through an orifice or over a rectangular weir.
Pump Horsepower CalculatorEstimate water horsepower, brake horsepower, and power demand.
Rational Method Runoff CalculatorEstimate peak runoff for small drainage areas.
Time of Concentration CalculatorEstimate runoff travel time to the design point.
Water Quality Volume CalculatorEstimate runoff volume for treatment sizing.
BMP Media Storage CalculatorEstimate media void storage and surface ponding storage.
Tank Drawdown CalculatorEstimate drawdown time for tanks and cisterns.
Water Engineer Unit ConverterConvert common flow, volume, rainfall, and power units.
Need help checking a water calculation?
Use these calculators for planning checks and learning. For project-specific review, calculation assumptions, or design support, send the basic project details for a more focused review.
Need help reviewing this result?
Use this calculator for planning-level checks, then request help if you need a second look at assumptions, units, stormwater criteria, pump sizing, storage volume, or report-ready calculations.