Equipment Electricity Cost
Estimate electricity use from input power, equipment count and operating time. Apply your energy rate and a separately entered monthly charge.
Use equipment electricity cost →CALCULATORS BY INDUSTRY
Water & wastewater calculators
Calculate flow, residence, concentration, mass loading and water-cost relationships.
20 free tools. No signup. Methods, examples and source links on every page.
Savings Project Simple Payback
Separate annual gross savings from added operating cost and compare the net saving with upfront project cost.
Use savings project simple payback →Water Leak Cost
Turn a measured or assumed constant leak rate into volume, avoidable water and sewer charges, and a simple repair recovery ratio.
Use water leak cost →Water Flow Unit Conversion
Convert a steady volumetric flow between liters per minute, liters per second, cubic meters per hour and U.S. gallons per minute.
Use water flow unit conversion →Liquid Mass & Volume
Estimate liquid mass from volume, or volume from mass, using your entered density. See liters, cubic meters, kilograms, tonnes and pounds together.
Use liquid mass & volume →Motor Efficiency Savings
Convert the same mechanical shaft output through two entered efficiencies, then compare annual energy charges and simple payback.
Use motor efficiency savings →Flow-Weighted Concentration
Calculate a nonreactive combined concentration from up to three matched stream flows and constituent concentrations. See each stream’s contribution to the total mass rate.
Use flow-weighted concentration →Hydraulic Retention Time
Calculate nominal hydraulic retention time from working liquid volume and representative throughflow. Keep the ideal ratio separate from real mixing or treatment performance.
Use hydraulic retention time →Wastewater Mass Loading
Estimate a daily constituent mass rate from representative liquid flow and mg/L concentration. Extend the same constant conditions over an entered period.
Use wastewater mass loading →Pipe Flow Velocity
Calculate pipe velocity from flow rate and actual internal diameter. Enter L/s, L/min, m³/h or U.S. gpm with mm or inches, and see mean velocity in m/s and ft/s.
Use pipe flow velocity →Commercial Water & Sewer Cost
Assemble two water tiers, a separately entered sewer billing quantity, fixed charges and a signed adjustment.
Use commercial water & sewer cost →Tank Fill & Drain Time
Calculate ideal inventory-change time from simultaneous constant inflow and outflow.
Use tank fill & drain time →Pipe Pressure-Drop Scenario
Convert diameter to metres and flow to m³/s.
Use pipe pressure-drop scenario →Pump Affinity Law Scenario
For an ideal fixed-geometry centrifugal-pump similarity scenario, r = new speed / reference speed.
Use pump affinity law scenario →Pump Hydraulic Power
Hydraulic kW = fluid density × standard gravity 9.80665 m/s² × flow in m³/s × differential head in metres ÷ 1,000.
Use pump hydraulic power →Reynolds Number
Dynamic-property mode uses Re = density × velocity × characteristic length ÷ dynamic viscosity.
Use reynolds number →Sludge Retention Time Scenario
Nominal solids retention time in days = solids inventory in kilograms ÷ (external wasted solids + external effluent solids in kg/day).
Use sludge retention time scenario →Solution Dilution Arithmetic
On matching compatible mass-per-volume or molar concentration bases, stock concentration × stock volume = target concentration × final solution volume.
Use solution dilution arithmetic →Treatment Concentration & Mass Removal
Concentration reduction percent = (inlet − outlet concentration) ÷ inlet concentration × 100.
Use treatment concentration & mass removal →Wastewater Solids Inventory
Estimated solids kilograms = working liquid volume in m³ × representative concentration in mg/L × 0.001.
Use wastewater solids inventory →Before you use these calculations
Pair flow and concentration measurements from compatible conditions and intervals.
Keep hydraulic residence time separate from solids retention or treatment performance.
Calculations do not determine permit limits, chemical dose recommendations or discharge compliance.
Start with the example, replace the assumptions with your measurements, then change one input to see its effect. Save or export the scenario if you need to keep its basis.
How Case calculators are built and checked →Read practical calculation guides or browse another industry.