Calculator Inputs
Enter the linear movement in cm/hr. Then define the open area that liquid passes through.
Formula used
The conversion needs a cross-sectional area. A movement of 1 cm through 1 cm² creates 1 cm³. One cubic centimeter equals one milliliter.
Area from diameter: A = π × (d ÷ 2)²
Area from radius: A = π × r²
Rectangular area: A = width × height
Effective area: Aeffective = A × channels × efficiency ÷ 100
Main conversion: mL/min = (cm/hr × Aeffective) ÷ 60
How to use this calculator
- Enter the linear rate in centimeters per hour.
- Select how you want to define the open area.
- Enter diameter, radius, rectangular size, or known area.
- Add channel count when several identical paths flow together.
- Use efficiency when the open path is partly blocked.
- Enter density, batch volume, or target flow when needed.
- Press calculate. The result appears above the form.
Example data table
| Speed | Area input | Effective area | Calculation | Flow |
|---|---|---|---|---|
| 10 cm/hr | 2 cm² custom area | 2 cm² | (10 × 2) ÷ 60 | 0.3333 mL/min |
| 5 cm/hr | 1 cm diameter | 0.7854 cm² | (5 × 0.7854) ÷ 60 | 0.0654 mL/min |
| 12 cm/hr | 2 cm × 3 cm channel | 6 cm² | (12 × 6) ÷ 60 | 1.2000 mL/min |
| 8 cm/hr | 1.5 cm², 4 paths, 90% | 5.4 cm² | (8 × 5.4) ÷ 60 | 0.7200 mL/min |
Understanding the Conversion
Cm/hr is a linear speed. It tells how far a liquid front moves in one hour. mL/min is a volume flow rate. It tells how much liquid moves each minute. To move between these units, area must be known. Without area, the conversion is incomplete. A narrow tube and a wide tube can share the same cm/hr speed. They will not deliver the same volume.
Why Area Matters
The calculator treats one cubic centimeter as one milliliter. First it finds cross sectional area in square centimeters. Then it multiplies area by speed. The result is cubic centimeters per hour. Since cubic centimeters equal milliliters, the value is also mL/hr. Dividing by sixty changes the result into mL/min. This method works for circular tubes, rectangular channels, trays, columns, and other straight passages.
Useful Input Choices
Many users know diameter, not area. The tool can calculate circular area from diameter. It can also use radius directly. For flat channels, it uses width times height. For tested systems, custom area is often best. You can enter measured area from drawings or lab notes. Channel count helps when identical passages work in parallel. Efficiency corrects for screens, packing, fouling, or partial blockage. These options make the result closer to a real setup.
Common Applications
This conversion appears in filtration, irrigation, chromatography, dosing, and seepage tests. It is also useful in soil columns. A seepage velocity in cm/hr can become a pump flow in mL/min. A lab technician can scale a small test to several tubes. A field engineer can compare infiltration speed with collected outflow. A designer can estimate discharge from a channel. The same formula stays simple, but the area choice changes the answer.
Accuracy Tips
Use consistent units before entering values. Diameter, radius, width, height, and area should all be in centimeters. Do not enter millimeters unless you convert them first. Measure inside dimensions for pipes and tubes. Outside diameter can overstate flow. Use a realistic efficiency value when the path is not fully open. Round the final result only after the calculation. Small areas can make tiny flows, so keep enough decimals.
Interpreting Results
The result panel shows area, hourly volume, minute flow, and mass flow when density is entered. It also shows each step. This makes review easier. If the value looks too high, check the area and channel count first. If it looks too low, check whether the speed was entered per hour. The calculator is a planning aid. Final designs should still match test data and process requirements.
Good Workflow
Start with one clean measurement. Choose the area method that matches your equipment. Enter the open path count. Add efficiency only when flow is reduced. Compare the result with a measured collection test. Save the CSV record for reports. Use the print option when a signed calculation sheet is needed for review and documentation later.
FAQs
Can cm/hr be converted to mL/min directly?
No. Cm/hr is linear speed. mL/min is volume flow. You must know the cross-sectional area. The calculator multiplies speed by area, then divides the hourly volume by 60.
Why does tube diameter change the result?
Diameter controls circular area. Area rises with the square of diameter. A small diameter increase can create a much larger flow rate when the same cm/hr speed is used.
What area unit should I use?
Use square centimeters. Diameter, radius, width, and height should also be in centimeters. Convert millimeters, meters, or inches before entering values.
Does 1 cm³ always equal 1 mL?
Yes. One cubic centimeter equals one milliliter by volume. This is the key link between linear movement through area and liquid flow rate.
What does efficiency mean here?
Efficiency is the usable open area percentage. It can represent screens, packing, blockage, fouling, or partial opening. Use 100 percent when the full area is open.
Can I use this for several tubes?
Yes. Enter the area for one identical tube. Then enter the number of open paths. The calculator multiplies the single area by that count.
Can this calculator estimate mass flow?
Yes. Enter density in g/mL. The calculator multiplies mL/min by density to estimate g/min, then converts that value to kg/hr.
What if my flow path is not round?
Use the rectangular channel option if the path has width and height. Use the custom area option for irregular shapes, measured drawings, or lab-tested open area.
Why is my result very small?
Small areas and slow speeds produce tiny volumes. Increase displayed decimals to see more detail. Also check that the speed was entered in cm/hr, not cm/min.
Can I find the speed needed for a target flow?
Yes. Enter a target flow in mL/min. The tool divides the target by effective area and converts the result back to cm/hr.
Is this suitable for final engineering design?
It is a calculation aid. Use it for planning, checks, and documentation. Final designs should also consider pressure, viscosity, losses, calibration, and field test data.