Is the operator calculator free, and do I need to sign up?

Yes, it is free and there is no signup or login. Open the page and start calculating. The whole tool runs in your browser.

What formulas does it use?

It follows WPI/ABC (Association of Boards of Certification) exam conventions. Dosage and loading use 8.34 pounds per gallon; unit conversions use precise factors. It covers SVI, F/M ratio, MCRT/sludge age, well drawdown and specific capacity, chlorine dosage, CT disinfection, detention time, surface and organic loading, population equivalent, pump horsepower, and more.

Operator Calculator

Water & wastewater system math

Pick units per field · enter decimals (1'6" = 1.5')

Built by people who actually run small systems

Ziptility puts your map, assets, work orders, and compliance records in one place ‚Äî no GIS degree required. These numbers are easier to track when they live in your system, not a clipboard.

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A free calculator for water and wastewater operators

Running a small water or wastewater system means doing the math yourself ‚Äî often in the field, often without a second set of eyes. This is a free set of operator calculators for the everyday numbers: the ones that show up on certification exams and on your daily logs. Pick water or wastewater, choose units per field, and enter what you know. Most cards solve in any direction, so you can fill in all but one value and let the tool find the rest.

It is built for the people who actually run small and rural systems. No login, no signup, and no GIS background required. The formulas follow WPI / ABC (Association of Boards of Certification) exam conventions, dosage and loading use 8.34 pounds per gallon, and unit conversions use precise factors. Many results include a plain-English note ‚Äî for example, whether an SVI suggests good or bulking sludge, or whether a BOD/TSS removal meets the 85% secondary-treatment minimum.

What you can calculate

More than 50 calculators across eleven categories. Geometry and volume: rectangle, triangle and circle area, circumference, and tank volumes (rectangular, cylinder, cone/hopper, sphere). Flow and pressure: gpm to MGD, detention time, velocity, pressure and head, and lift-station cycle time. Treatment and filtration: CT disinfection with a compliance ratio, and filtration/backwash rate. Process control: F/M ratio, MCRT and sludge age (SRT), return (RAS) rate, and recirculation ratio. Solids and settling: sludge volume index (SVI), suspended and total solids, percent removal, and volatile solids. Wells and distribution: well drawdown and specific capacity, water-loss summary, and water use (gpcd). Dosage and chemical: chlorine dosage, chemical feed rate, dilution, and concentration. Pumps and power: brake, water, and motor horsepower, wire-to-water efficiency, Ohm's law, and electrical power. Lab: alkalinity, hardness, and BOD. Plus length, area, volume, weight, and flow unit conversions and specific gravity.

Common questions

Is it free, and do I need to sign up?

Yes, it is free, with no signup or login. Open it and start calculating ‚Äî the whole tool runs in your browser.

Who is it for?

Water and wastewater operators at small and rural systems, and anyone studying for a certification exam who needs the everyday math fast.

Are the results official?

No. It is a working aid, not a substitute for your own check, your system's engineering, or regulatory requirements. Verify any number that drives a compliance, dosing, or safety decision.