Is the TR to CFM Calculator free to use?

Yes. The TR to CFM Calculator is a free browser-based planning calculator from I Love MEP.

Can the TR to CFM Calculator be used for final engineering design?

No. The result is for planning, tender review, and coordination support. Final design must be checked by a qualified engineer against project specifications, authority requirements, and applicable standards.

Does the PDF report replace approved design calculations?

No. The PDF report records inputs, assumptions, warnings, and planning results. It should be reviewed before any construction, procurement, or authority submission decision.

TR to CFM Calculator

TR to CFM calculator for HVAC supply airflow planning. Convert cooling tons to CFM using CFM per ton, outdoor air allowance, and design margin.

Last updated: July 27, 2026

What is a TR to CFM calculator?

A TR to CFM calculator converts cooling capacity in tons of refrigeration into the supply airflow normally used for HVAC planning. Engineers use it when a room, zone, AHU, FCU, or packaged unit already has a cooling load but the airflow still needs a quick reasonableness check. The calculator multiplies TR by a selected CFM per ton value, adds any outdoor air allowance, and applies design margin. It is useful for early duct sizing, diffuser coordination, air balancing expectations, equipment schedule checks, and comparing consultant or contractor assumptions. The result is not a final air distribution design because real projects still need room loads, ventilation code checks, static pressure, filtration, acoustics, diversity, and equipment selection. Use it as a fast first pass before detailed HVAC calculation. For best results, keep the entered units consistent, load the sample first, then adjust one assumption at a time so the result can be reviewed and explained.

Inputs

Forms are empty on load. Use sample data to preview the workflow or enter your own project values.

Video tutorial

Watch a quick walkthrough with sample inputs, calculation flow, and result interpretation.

Open the TR to CFM Calculator tutorial on YouTube

Learn more

Formula logic, assumptions, limits, and worked-use guidance for this calculator.

How this tool helps

Use this for quick HVAC checks when a cooling load is known in tons and the team needs a practical supply airflow value. The selected profile can raise low CFM/TR inputs to conservative planning assumptions.

Calculation methodology

Base airflow = cooling tons x CFM per ton. Ventilation CFM is added separately, then design margin is applied.

View full methodology notes

Assumptions and limits

This is a planning-level calculator. Final decisions should be checked against approved project standards, local authority requirements, manufacturer data, and qualified engineering review.

Version history

v1.3.7-prelaunch: Added after keyword gap review for TR to CFM and CFM per ton search demand.

Input definitions and typical values

These notes explain what each input means and which values usually produce a more reliable planning result.

Code / standard profile

Selects the planning profile used for conservative defaults. Use the project authority or client standard where known; otherwise use the closest regional profile. Options: GCC project planning, ASHRAE planning, CIBSE planning.

Cooling load TR

Cooling capacity in refrigeration tons. 1 TR equals about 3.517 kW; use calculated load where possible, not only area rule of thumb.

Supply airflow per ton CFM/TR

Supply airflow per refrigeration ton. A common planning range is 350-450 CFM/TR; 400 CFM/TR is often used for comfort cooling checks.

Outdoor air allowance CFM

Outdoor air per person. Typical planning values are often 8-10 L/s/person, subject to standard, occupancy type, and indoor air quality target.

Design margin %

Design safety margin. 5-15% is common for planning; excessive margin can oversize equipment, cables, pumps, or tanks.

Practical verification checklist

Confirm the selected standard profile is suitable for the project location and authority.
Replace sample values with project drawings, schedules, equipment data, or measured site values.
Review warnings, methodology, and PDF report before using the result outside early planning.
Verify final decisions against official standards, manufacturer data, consultant specifications, and local approvals.

Standards references for verification

For final design checks, verify calculator assumptions against the project documents and official standards bodies such as ASHRAE, NFPA, IEC, IET BS 7671, ICC, and CIBSE.