Molar Flow Converter
ScienceConvert molar flow rate between moles per second, moles per hour, kilomoles per hour, and pound-moles per hour — used for chemical engineering.
From
To
All conversionsfor 1 Moles per Hour (mol/hr)
| Moles per Second (mol/s) | 0.000277778 |
| Moles per Minute (mol/min) | 0.016666647 |
| Moles per Hour (mol/hr) | 1 |
| Kilomoles per Hour (kmol/hr) | 0.001 |
| Pound-Moles per Hour (lb-mol/hr) | 0.0022046223 |
What is a Molar Flow?
The Molar Flow Converter converts molar flow rate between moles per second, moles per minute, moles per hour, kilomoles per hour, and the US customary pound-moles per hour. Molar flow rate measures how many moles of a substance pass a point per unit time — the natural unit for chemical reaction calculations, since reactions proceed according to molar stoichiometric ratios rather than mass ratios.
Enter a value in any supported unit and the converter calculates the equivalent instantly. For the related mass-based quantity, see the Mass Flow Converter.
How to use this Molar Flow calculator
- Choose your starting unit from the source dropdown — for example, "Moles per Hour (mol/hr)".
- Enter the numeric value you want to convert in the input field.
- Choose your target unit from the destination dropdown — for example, "Kilomoles per Hour (kmol/hr)".
- Read the converted result, which updates instantly as you type or change units.
- Use the swap (⇅) button if you need to reverse the conversion direction.
- Use the copy button to grab the result for a reactor design calculation or process flow diagram.
Formula & Methodology
The converter's base unit is moles per second (mol/s). Every supported unit has a fixed multiplier: - 1 mole per minute (mol/min) = 0.016667 mol/s - 1 mole per hour (mol/hr) = 0.000278 mol/s - 1 kilomole per hour (kmol/hr) = 0.277778 mol/s - 1 pound-mole per hour (lb-mol/hr) = 0.125998 mol/s Any conversion follows: Result = Input × (toBase of source unit ÷ toBase of target unit) Worked example — converting 10 kmol/hr to mol/s: Result = 10 × (0.277778 ÷ 1) = 2.778 mol/s This is the value you'd use directly in an SI-unit reaction kinetics calculation.
Frequently Asked Questions
Molar flow rate measures how many moles of a substance pass a given point per unit time, expressed in units like moles per second — commonly used in chemical engineering and reaction kinetics, where reaction rates and stoichiometry are naturally expressed in moles rather than mass.
Divide the mol/hr value by 1,000, since one kilomole equals 1,000 moles. Enter your value with 'Moles per Hour (mol/hr)' as the source and 'Kilomoles per Hour (kmol/hr)' as the target to apply this automatically.
Chemical reactions proceed according to molar stoichiometric ratios (like 2 moles of hydrogen reacting with 1 mole of oxygen), not mass ratios, so expressing flow rates in moles makes reactor design and reaction rate calculations far more direct than converting through mass and molecular weight repeatedly.
Multiply the molar flow rate by the substance's molar mass (mass flow = molar flow × molar mass) — see the [Mass Flow Converter](/mass-flow-converter/) for the resulting mass-based flow unit conversions.
A pound-mole (lb-mol) is the US customary equivalent of a mole, defined so that one lb-mol contains a mass in pounds numerically equal to the substance's molecular weight — just as one mole of a substance weighs its molecular weight in grams. It's used to keep US-based process calculations consistent with pound-based mass units.
This varies enormously by reactor scale and reaction type — laboratory-scale reactions might involve millimoles per second, while large industrial reactors can process kilomoles per hour or more, so context determines what's typical for a specific process.
For gases, molar flow rate relates directly to volumetric flow rate through the ideal gas law (PV = nRT), making molar flow a natural unit for gas process calculations where pressure and temperature significantly affect volume.
Kilomoles per hour keeps typical industrial process stream numbers in a convenient, readable range — expressing large-scale plant flows in mol/s would produce awkwardly large numbers, so kmol/hr is the conventional unit on most process flow diagrams and mass/mole balance sheets.
The unit conversion itself (mol/s to kmol/hr, for example) works the same regardless of substance, but converting a molar flow rate to mass flow rate requires the specific substance's molar mass, which differs for every chemical compound.
Chemical processing, petrochemical refining, pharmaceutical manufacturing, and any industry involving chemical reactions or gas processing rely heavily on molar flow rate for reactor design, mass balance calculations, and process control.
Also known as