Free MEP Engineering Calculators
Free engineering calculators — the same ones our engineers use to answer the plan-review comments cities ask for most. Each produces a plan-ready table you can copy into Excel or drop into your drawing. Preliminary values; your engineer of record verifies final numbers against your adopted code edition.
Mechanical
Outdoor Air / Ventilation
ASHRAE 62.1 · IMC Table 403.3.1.1
Add each room with its occupancy category and area. You get the required outdoor air per room and the building total, as a table for the mechanical plans.
Open the calculatorDuct Sizing
Equal-friction method
Enter the airflow and the friction rate you are designing to. You get round and rectangular sizes, velocity and velocity pressure for every run.
Open the calculatorExhaust + Makeup Air
IMC 403.3 · 507.5 · 508.1
Enter restroom fixture counts or hood dimensions. You get the exhaust rate and the makeup air needed to balance it.
Open the calculatorHydronic Pipe / GPM
BTU/h and design delta-T
Enter the load and the delta-T you are designing around. You get GPM, copper pipe size, velocity and friction head per leg.
Open the calculatorEquipment Quick-Size
Tons, CFM/ton · ACCA Manual S
Enter the cooling load. You get tons, the airflow that goes with it, and a check against the Manual S oversizing limits.
Open the calculatorPlumbing
Plumbing Fixture Count
IBC Table 2902.1
Enter the occupancy and occupant load. You get the required water closets, lavatories, drinking fountains and service sinks.
Open the calculatorWater + Drainage Fixture Units
WSFU / DFU · editable per adopted code
Enter fixture quantities. You get WSFU and DFU totals and the building drain size, with the unit table editable to your code edition.
Open the calculatorGas Pipe Sizing
Longest-length method
Enter appliance loads and the longest developed run. You get the complete riser data table to put on the drawings.
Open the calculatorWater Service + Meter Sizing
IPC Appendix E (E103)
Enter fixture units and the pressure available at the main. You get demand GPM, the pressure budget, and the service pipe and meter size.
Open the calculatorWater Heater Sizing
First-hour rating · ASPE recovery
Enter the fixture mix and peak demand. You get a residential first-hour rating, or commercial recovery and storage.
Open the calculatorStorm / Roof Drainage
IPC 1106
Enter roof area per drain and your local rainfall rate. You get roof drains, vertical leaders and horizontal storm piping.
Open the calculatorVent Sizing
IPC Table 916.1
Enter the drainage stack size, connected fixture units and developed length. You get the vent stack size.
Open the calculatorElectrical & life safety
Panel Load
NEC Article 220
List the connected loads. Demand factors are applied to return the demand load in amps and the spare capacity actually left.
Open the calculatorOccupant Load + Egress
IBC 1004.5 · 1005.3 · 1006.2
Enter areas and occupancy types, and say whether the building is sprinklered. You get occupant load, required egress width and exit count.
Open the calculator14 calculators, each on its own page. Results are preliminary — your engineer of record verifies final values against the code edition your jurisdiction has adopted.
Complete MEP permit set built to get approved.
Every mechanical, electrical, plumbing, and fire sheet your reviewer needs — a fixed quote in 24 business hours, first sets in as few as 5 working days, and city comments answered until your permit is issued.