Calculator Inputs
Formula Used
Volume and time: Flow (LPM) = Volume (L) ÷ Time (min)
Pipe velocity: Flow (LPM) = Velocity × Area × 1000 × 60
Pipe area: Area = π × d² ÷ 4, where diameter is in meters.
Tank fill or drain: Flow (LPM) = Changed Volume (L) ÷ Time (min)
Conversion mode: Flow (LPM) = Source Value × Unit Conversion Factor
How to Use This Calculator
- Select the calculation mode that matches your available data.
- Enter values for volume, time, pipe size, velocity, or source flow units.
- Choose the preferred number of decimal places for reporting.
- Add a safety factor if you want a design flow above the base result.
- Click Calculate Flow Rate to show the result above the form.
- Review equivalent flow units and the Plotly graph for quick comparisons.
- Use the CSV or PDF buttons to export your result set.
Example Data Table
| Scenario | Inputs | Base Flow (LPM) | Design Flow at 10% (LPM) |
|---|---|---|---|
| Volume and time | 120 L in 4 min | 30.00 | 33.00 |
| Pipe velocity | 50 mm pipe at 1.8 m/s | 212.06 | 233.27 |
| Tank fill | 800 L tank, 75% change, 12 min | 50.00 | 55.00 |
| Unit conversion | 25 US GPM | 94.64 | 104.10 |
FAQs
1. What does LPM mean?
LPM means liters per minute. It expresses how many liters move through a system every minute. It is common in pumps, water lines, dosing systems, test rigs, and automation dashboards.
2. How do I calculate LPM from volume and time?
Divide the transferred volume in liters by the elapsed time in minutes. If your time is in seconds or hours, convert it to minutes first, then apply the same formula.
3. How do I calculate flow from pipe velocity?
Find the pipe cross-sectional area from the inner diameter, multiply it by fluid velocity, then convert cubic meters per second into liters per minute. This method is useful when a flowmeter is unavailable.
4. Why use a safety factor?
A safety factor adds design margin above the measured or calculated base flow. It helps account for variation, fouling, future demand, and normal uncertainty during sizing or specification work.
5. Can this calculator convert other flow units?
Yes. The conversion mode accepts LPM, LPS, LPH, cubic meters per hour, cubic meters per second, US gallons per minute, and UK gallons per minute.
6. Is this calculator useful for software projects?
Yes. Developers can use it when building monitoring tools, industrial interfaces, IoT dashboards, telemetry parsers, digital twins, or reporting systems that display fluid movement and equipment performance.
7. What is the difference between base flow and design flow?
Base flow is the direct calculated result from your inputs. Design flow includes the extra percentage margin you set with the safety factor for planning, procurement, or control logic.
8. Can I export my results?
Yes. After calculation, use the CSV button for spreadsheet-ready output or the PDF button for a clean snapshot that includes the visible result section and chart.