Fast field calculators for HVAC, Plumbing & Electrical
plumbing calculator workflow
Pipe, slope, heater, and flow calculators for practical plumbing estimates.
Choose a path based on the system question: supply sizing, drainage layout, hot water demand, or pipe volume.
Start with demand, then check sizing and pressure-loss assumptions.
Convert slope rules into fall, then check capacity where needed.
Estimate demand before selecting a product class.
Common starting points for quick planning and assumption checks.
Estimate recommended storage water heater gallons from occupants, bathrooms, and simultaneous hot-water demand for repla...
Open calculatorEstimate nominal supply pipe size from fixture count, run length, and material assumptions to support quick planning bef...
Open calculatorCalculate total vertical drop for drain runs from slope per foot so plumbing crews can set elevations quickly and avoid...
Open calculatorUse these groups to move from an initial estimate to the next practical check.
Use these when fixture demand, pipe size, flow, or pressure loss is the core question.
Plan gravity drainage, sewer capacity, sump sizing, and septic tank assumptions.
Estimate stored hot water or tankless demand before comparing manufacturer data.
Use these for contained volume, dosing, flushing, or service-capacity planning.
Estimate recommended storage water heater gallons from occupants, bathrooms, and simultaneous hot-water demand for replacement and planning decisions.
Open calculatorEstimate nominal supply pipe size from fixture count, run length, and material assumptions to support quick planning before detailed code checks.
Open calculatorCalculate total vertical drop for drain runs from slope per foot so plumbing crews can set elevations quickly and avoid low-slope drainage issues.
Open calculatorEstimate total and diversified fixture flow demand in GPM so plumbing teams can plan supply sizing and evaluate expected peak usage patterns.
Open calculatorEstimate domestic hot-water expansion tank size from system volume, pressure, and temperature rise to support safer plumbing system setup.
Open calculatorEstimate tankless heater BTU/hr from simultaneous flow and temperature rise to shortlist practical whole-home size classes.
Open calculatorEstimate straight-run water pressure loss with a simplified Hazen-Williams method for planning-level pipe checks.
Open calculatorEstimate full-flow sewer capacity and velocity using Manning-based assumptions for quick drainage planning checks.
Open calculatorEstimate required sump pump flow with safety margin and suggest an initial HP class for planning checks.
Open calculatorCalculate pipe internal volume in gallons, liters, and cubic feet from diameter and run length for planning and flushing estimates.
Open calculatorEstimate well pump TDH and flow target to suggest a planning-level HP class before validating with actual pump curves.
Open calculatorEstimate septic tank volume from bedrooms, occupants, and daily flow assumptions with reserve margin and standard-size suggestions.
Open calculatorEstimate grease interceptor volume from flow and retention assumptions or fixture volume inputs for early commercial kitchen planning.
Open calculatorPlumbing guide
Pipe sizing is a chain of assumptions: demand, length, material, pressure, and fixture performance all matter.
Plumbing guide
Drain slope calculations are simple mathematically, but layout decisions still depend on pipe size, fixtures, and code requirements.
Plumbing guide
Water heater sizing is driven by peak use, not just the number of people in a home or building.
Plumbing
The most common planning errors in pipe sizing and how to catch them before install.
Plumbing
Learn how to estimate tank size from real usage patterns and avoid undersized or oversized water heater selections.
These calculators support early planning and field checks. Final decisions should account for site conditions, adopted local codes, manufacturer data, and licensed trade review where required.