Wastewater Operator Calculator

The professional wastewater calculator is built for licensed operators.

16 essential calculations covering Class I through Class IV certification math — from basic Pounds formulas to MCRT, F/M Ratio, and Volatile Solids Reduction. Every result shows the formula and your substituted values so you can verify the math yourself.

CALCULATORS INCLUDED: Hydraulics & Loading • Pounds / Mass Loading (lb/day = MGD × mg/L × 8.34) • Flow Rate Conversions (MGD, GPM, GPD, cfs) • Detention Time (accepts GPD, MGD, or GPM) • Percent Removal • Chemical Dose / Feed Rate (dry and liquid with SG) • Surface Overflow Rate (SOR)

Solids Control • Sludge Volume Index (SVI) • Return Activated Sludge Rate (RAS %) • MLSS / MLVSS Inventory • RAS Solids Balance

Process Control • Sludge Age — Basic (Class I/II) • MCRT / SRT — Full (Class III/IV, includes effluent SS) • F/M Ratio • Solids Loading Rate • OUR / SOUR • Volatile Solids Reduction (Van Kleeck)

BUILT FOR THE FIELD: • Works 100% offline — concrete bunkers, underground pump stations, rural facilities • Large, readable results designed for gloved hands • "Show Your Work" expands to show your exact values substituted into the formula • Copy Result pastes a formatted summary ready for texts or emails to your supervisor • Formula reference screen with all formulas, variables, and source attribution • Calculation history saves your last 20 results • Dark mode support

SHOW YOUR WORK: Every result displays the formula that produced it. Tap "Show Your Work" to see your actual input values plugged into the equation — the same way you'd show work on a certification exam.

Based on ABC, Sacramento State OIT, and state certification formula sheets.