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Mass Flow Converter

Science

Convert mass flow rate between kilograms per second, kilograms per hour, pounds per hour, and grams per second — used for process and fluid engineering.

Reviewed by the thecalcu.com team · Last updated July 26, 2026

From
To
All conversionsfor 1 Kilograms per Hour (kg/hr)
Kilograms per Second (kg/s)0.000277778
Kilograms per Minute (kg/min)0.016666647
Kilograms per Hour (kg/hr)1
Grams per Second (g/s)0.277778
Metric Tons per Hour (t/hr)0.001
Pounds per Second (lb/s)0.00061239616
Pounds per Hour (lb/hr)2.2046223

What is a Mass Flow?

The Mass Flow Converter converts mass flow rate between kilograms per second, kilograms per minute, kilograms per hour, grams per second, metric tons per hour, and the imperial pounds per second and pounds per hour. Mass flow rate measures how much mass of a substance moves past a point per unit time, a fundamental quantity in process engineering, particularly for gases and compressible flows where volumetric flow can vary with conditions.

Enter a value in any supported unit and the converter calculates the equivalent instantly. For the related molar quantity, see the Molar Flow Converter, and for volumetric flow, see the Flow Converter.

Why Use a Mass Flow Converter?

Process engineering datasheets and equipment specifications report mass flow rate in whatever unit matches the scale and region, small laboratory processes in grams per second, industrial plants in tons per hour, and US equipment in pounds per hour. Comparing or combining flow data across these scales and unit systems requires accurate conversion.

Who Should Use This Converter?

  • Process and chemical engineers converting mass flow rate data across equipment specifications from different manufacturers or regions.
  • Plant operators comparing production throughput figures reported in different units.
  • Mechanical engineering students working through fluid dynamics or thermodynamics problems that mix mass flow units.
  • Oil, gas, and power generation engineers working with mass balance calculations across mixed unit sources.

What Insights Does the Mass Flow Converter Give You?

The main output is the converted value in your chosen target unit, calculated precisely from the fixed multiplier relationship between units. Because mass flow rate spans a huge practical range, from grams per second in a lab to tons per hour in industrial plants, the converter helps confirm you're comparing values at a consistent, meaningful scale.

How to use this Mass Flow calculator

  1. Choose your starting unit from the source dropdown, for example, "Kilograms per Hour (kg/hr)".
  2. Enter the numeric value you want to convert in the input field.
  3. Choose your target unit from the destination dropdown, for example, "Kilograms per Second (kg/s)".
  4. Read the converted result, which updates instantly as you type or change units.
  5. Use the swap (⇅) button if you need to reverse the conversion direction.
  6. Use the copy button to grab the result for a process design calculation or mass balance report.
Show formula & methodology ↓Show less ↑

Formula & Methodology

The converter's base unit is kilograms per second (kg/s). Every supported unit has a fixed multiplier:

- 1 kilogram per minute (kg/min) = 0.016667 kg/s
- 1 kilogram per hour (kg/hr) = 0.000278 kg/s
- 1 gram per second (g/s) = 0.001 kg/s
- 1 metric ton per hour (t/hr) = 0.277778 kg/s
- 1 pound per second (lb/s) = 0.453592 kg/s
- 1 pound per hour (lb/hr) = 0.000126 kg/s

Any conversion follows:

Result = Input × (toBase of source unit ÷ toBase of target unit)

Worked example, converting 500 kg/hr to kg/s:

Result = 500 × (0.000278 ÷ 1) = 0.139 kg/s

This is the value you'd use directly in an SI-unit process engineering calculation.

Frequently Asked Questions

What is mass flow rate?
Mass flow rate measures how much mass of a substance passes a given point per unit time, expressed in units like kilograms per second, distinct from volumetric flow rate, which measures volume per unit time and doesn't account for the substance's density.
How do I convert kg/hr to kg/s?
Divide the kg/hr value by 3,600, since there are 3,600 seconds in an hour. Enter your value with 'Kilograms per Hour (kg/hr)' as the source and 'Kilograms per Second (kg/s)' as the target to apply this automatically.
Why is mass flow rate preferred over volumetric flow rate in some engineering contexts?
Mass flow rate stays constant even as a fluid's density changes with temperature or pressure (relevant for gases and compressible flows), while volumetric flow rate can vary under the same conditions, this makes mass flow rate the more fundamental and reliable quantity for many process engineering calculations, particularly involving gases.
How do I convert between mass flow rate and volumetric flow rate?
Multiply or divide by the fluid's density, mass flow rate equals volumetric flow rate multiplied by density. Use the [Flow Converter](/flow-converter/) for volumetric flow units and the [Density Converter](/density-converter/) for density conversions to work through this relationship.
What is a typical mass flow rate for industrial process applications?
This varies enormously by application, a small laboratory process might involve grams per second, while a large industrial plant might handle hundreds of tons per hour, so there's no single typical value; context determines the appropriate scale.
How does mass flow relate to molar flow?
Molar flow rate measures the flow of moles of a substance rather than mass, and the two are related by the substance's molar mass (mass flow = molar flow × molar mass), see the [Molar Flow Converter](/molar-flow-converter/) for that related quantity, common in chemical engineering.
Why do process engineers use metric tons per hour for large-scale flows?
Metric tons per hour keeps large industrial mass flow numbers in a manageable range, expressing a plant's material throughput in kg/s would produce awkwardly small numbers for genuinely large flows, so t/hr is the conventional unit for bulk material handling and large process streams.
How is mass flow rate measured in practice?
Common measurement methods include Coriolis flow meters (which directly measure mass flow by detecting fluid-induced vibration changes), or indirect calculation from volumetric flow meter readings combined with a known or measured fluid density.
What industries rely heavily on mass flow rate calculations?
Chemical processing, oil and gas, power generation, food and beverage manufacturing, and pharmaceutical production all rely on accurate mass flow measurement and conversion for process control, material balance calculations, and regulatory reporting.
Can I use this converter for gas flow as well as liquid flow?
Yes, mass flow rate conversion works identically regardless of the substance's phase, since it's purely a mass-per-time relationship; this is actually one advantage of mass flow over volumetric flow, which behaves differently for compressible gases.
Also known as
mass flow rate converterkg/s to lb/hr convertermass flow converterkg per hour to kg per secondprocess engineering flow converter