LPM to CFM Calculator

Litres Per Minute to Cubic Feet Per Minute

LPM to CFM converts litres per minute, also written as liters per minute, into cubic feet per minute. Both units describe volumetric flow rate. LPM is common in metric airflow, pneumatic, laboratory gas, and process documents, while CFM is common in HVAC, ventilation, air compressor, duct, and North American airflow specifications.

Key Engineering Entities

This page references litres per minute (LPM), cubic feet per minute (CFM), HVAC, ventilation, air compressors, duct systems, ASHRAE, SMACNA, AMCA, CAGI, and ISO 1217 because those entities commonly appear around airflow conversion work.

Convert LPM to CFM Instantly

The LPM to CFM calculator above requests a value in litres per minute and returns the equivalent airflow in cubic feet per minute. It is designed for fast unit checks when a metric flow meter, rotameter, fan schedule, laboratory gas panel, or pneumatic datasheet must be compared with CFM-based equipment.

Default example: 100 LPM = 3.531 CFM.

Direct Volume Flow Conversion

To convert LPM to CFM, multiply the LPM value by 0.0353147. The factor comes from the relationship between one litre and one cubic foot: 1 cubic foot equals about 28.3168466 litres, so 1 litre equals about 0.0353147 cubic feet.

This is a unit conversion only. It does not correct airflow for pressure, temperature, humidity, gas composition, or standard conditions.

LPM and CFM Mean the Same Flow Type

Liters per minute to CFM is the same conversion as litres per minute to cubic feet per minute. The spelling differs by region, but the unit intent is identical: volume moved per minute. European and laboratory specifications often use L/min or LPM; US HVAC, compressor, and fan documents often use CFM.

Where the Units Appear

LPM appears on metric flow meters, medical gas flow devices, pneumatic regulators, and lab equipment. CFM appears in ASHRAE ventilation schedules, AMCA fan data, SMACNA duct design, and CAGI compressed-air equipment references.

Worked Calculation

For a metric airflow reading of 250 LPM, calculate CFM as 250 x 0.0353147 = 8.829 CFM. Use this result when comparing an LPM flow meter reading with a CFM fan, compressor, or ventilation schedule.

250 LPM = 8.829 CFM.

Exact Practical Value

1 LPM = 0.0353147 CFM. For quick mental checks, 1 LPM is about 0.0353 CFM, and 100 LPM is about 3.53 CFM.

Reverse Value

1 CFM = 28.3168466 LPM. Use the reverse factor when a CFM fan schedule or compressor datasheet must be written in metric LPM.

Why the Factor Works

A cubic foot contains about 28.3168466 litres. Dividing litres per minute by 28.3168466 gives cubic feet per minute. The shorter multiplier form is 0.0353147.

Quick Airflow Chart

The chart below uses the direct formula CFM = LPM x 0.0353147. It is useful for airflow conversion in ventilation, HVAC, pneumatic tools, gas-flow meters, and air compressor checks.

Example for a Metric Airflow Meter

A flow meter reads 300 LPM. To convert it to CFM, multiply 300 by 0.0353147. The result is 10.594 CFM. This can be used to compare a metric airflow reading with a US fan, air compressor, or duct-balancing report.

300 LPM x 0.0353147 = 10.594 CFM.

Actual CFM vs Standard CFM

LPM to standard CFM is not always the same as direct LPM to CFM. Standard CFM, often written as SCFM, corrects airflow to a reference pressure and temperature. Direct CFM uses actual volume flow at the measured condition.

Entity Notes

Compressed-air documents may reference ISO 1217, CAGI, SCFM, ACFM, barometric pressure, inlet temperature, and relative humidity. If the specification says standard flow, confirm the reference conditions before converting.

Using LPM as an Airflow Unit

LPM to air flow rate means converting a metric volumetric airflow reading into a unit used by the target system. For small flows, LPM is convenient. For ducts, fans, compressors, and ventilation schedules, CFM is often easier to compare with US equipment data.

Airflow conversion should be separated from airflow design. Duct sizing, fan static pressure, air changes per hour, and pressure drop still require engineering checks beyond the LPM to CFM unit conversion.

Room Airflow and Fresh Air

LPM to CFM for ventilation is used when fresh-air supply, exhaust airflow, or room ventilation data is provided in litres per minute but a schedule, balancing report, or code reference uses CFM. Ventilation work commonly references ASHRAE 62.1, ASHRAE 62.2, building occupancy, outdoor air rate, and exhaust air rate.

500 LPM ventilation air = 17.657 CFM.

Fans, Coils, Diffusers, and Balancing

LPM to CFM for HVAC helps compare metric airflow data with CFM-based air handlers, VAV boxes, grilles, diffusers, fan coils, and balancing reports. HVAC entities include ASHRAE, AHRI, AMCA, fan static pressure, supply air, return air, outside air, and exhaust air.

Use the calculator for unit conversion, then verify the full HVAC design against the project airflow schedule and equipment submittals.

Compressed Air and Pneumatic Tools

LPM to CFM for air compressors is used when compressor output, pneumatic tool demand, or air-consumption data is listed in LPM and the compressor catalogue uses CFM or SCFM. Common entities include Atlas Copco, Ingersoll Rand, Kaeser, Sullair, CAGI, ISO 1217, receiver tank, free air delivery, and working pressure.

For compressor sizing, confirm whether the value is ACFM, SCFM, FAD, or displaced volume. Those terms can change the interpretation even when the unit conversion is correct.

Duct Balancing and Air Distribution

LPM to CFM for duct systems is useful when duct branch flow, diffuser flow, or exhaust grille flow is measured with a metric instrument but the duct schedule uses CFM. Duct design commonly references SMACNA, ASHRAE, duct velocity, friction loss, static pressure, balancing dampers, and air terminals.

After converting LPM to CFM, check duct velocity and pressure drop separately because unit conversion does not confirm duct performance.

Reverse Conversion Example

A 10 CFM airflow reading equals 10 x 28.3168466 = 283.168 LPM. Use this when a CFM specification must be entered into a metric flow controller or LPM-based instrument.

Use CFM, LPM, SCFM, and m3/h Consistently

Airflow conversion keeps fan schedules, compressor datasheets, flow meters, pneumatic equipment, and duct measurements in the same unit system. LPM and CFM are both volumetric flow units, while SCFM adds standard-condition correction. For a simple unit conversion, use CFM = LPM x 0.0353147.

For engineering-critical applications, verify the converted value against manufacturer data, project specifications, and the required standard conditions.