Influent Flow Conversion Calculator

Calculator

Example data

Formula used

• Convert from the selected unit to a base flow: Q(m³/s) = Q(from) × factor(from→m³/s)
• Convert from base flow to your target unit: Q(to) = Q(m³/s) ÷ factor(to→m³/s)

How to use this calculator

1. Enter the influent flow value from measurement or design.
2. Select the unit that matches your input reading.
3. Select the output unit required for drawings or equipment.
4. Set decimal precision for reporting and calculations.
5. Click Convert flow to show results above.

Influent flow units used across project documents

Influent rates appear in civil drawings, process calculations, equipment schedules, and SCADA points. Designers often work in m³/day or MLD for capacity, while instruments and meters may output L/s or gpm. Converting to a consistent unit prevents misaligned peak factors, detention targets, and allowance checks during reviews.

Headworks checks for screens, grit, and channels

Screen approach velocity, grit chamber loading, and channel freeboard depend on instantaneous flow, not daily totals. A quick conversion from m³/day to L/s or cfs supports hydraulic section checks and avoids overestimating available head. When comparing alternatives, keep average, peak hourly, and storm bypass flows labeled in the same unit. If you track diurnal patterns, convert the peak fifteen‑minute rate before checking weir loading.

Pump station sizing and force main verification

Pump curves are commonly provided in gpm, but wet well modeling may use m³/h or L/min. Converting influent flow to the curve unit allows accurate duty point selection and confirms whether standby units meet peak flow. For force mains, use the converted rate to compute velocity and headloss, then document the unit used in the calculation sheet. This improves coordination when vendors submit curves in different unit systems.

Instrumentation, reporting, and compliance alignment

Regulatory reporting may request MGD or m³/day, while site operators monitor L/s trends. Conversions help set transmitter ranges, totalizer scaling, and alarm thresholds so that operational limits match permit language. Exported results can be attached to calibration records to show how displayed units relate to reported units. Use consistent rounding so dashboards and reports reconcile.

Quality control and handover documentation benefits

During submittals and commissioning, reviewers need a traceable path from field readings to design criteria. Converting through a base unit, such as m³/s, makes the factors auditable and reduces transcription errors. Use the CSV for spreadsheets and the PDF for packages, keeping input value, units, precision, and conversion date together for turnover. A standard conversion note also speeds up RFI responses and closeout verification.

FAQs

Which unit is best for design capacity checks?

Use the unit required by your design criteria, commonly m³/day or MLD. Convert field or vendor values to that unit so capacity, peaking, and storage calculations stay consistent.

Do gpm and MGD use US gallons?

Yes, gpm and MGD are based on US gallons in this calculator. If your project uses imperial gallons, apply the correct gallon factor before converting.

How should I convert peak versus average influent flow?

Convert each scenario separately using the same unit set. Label results as average, peak hourly, peak instantaneous, or bypass flow to avoid mixing criteria in reviews.

Why convert through a base flow first?

A base unit like m³/s standardizes every conversion pair. It makes factors easy to audit and reduces mistakes when switching between metric and US units.

What decimal precision should I select?

Use 2–4 decimals for reports and summaries. Increase precision for hydraulic checks, model inputs, or very small flows where rounding can change velocities and loads.

Can I attach results to submittals and QA records?

Yes. Download CSV for spreadsheets and PDF for packages. Exports capture input value, units, converted value, and the conversion basis for traceable documentation.