Certified Manual J Load Calculations — fast, accurate, permit-ready.
Upload your plans and get a same-day quote from a named, US-based, ACCA-certified designer. We handle Manual J, S, D, T, energy calculations, and permitting documents for residential and light commercial projects across the US, Canada, and Mexico.
Free DIY calculator vs. LoadCalcs
Free calculators are great for sketching. They are not permit-ready and they are not reviewed by a credentialed designer. We are both.
Free DIY tools
- Generic assumptions, no plan review
- Not signed or stamped
- Rejected by many AHJs for permits
- No accountability if numbers are wrong
- You do the data entry and the QA
LoadCalcs
- Reviewed plan-by-plan by an ACCA-certified designer
- Permit-ready reports accepted in 29+ states
- Same-day quote, 30-minute response window
- Named designer sees your project through to permit
- Revisions included if the AHJ pushes back
Three steps to a permit-ready report
Upload your plans
PDF, DWG, or images. Tell us the project type and your state — that's it.
Same-day quote
A real designer reviews your project and sends a fixed quote within hours.
Permit-ready report
Receive a stamped, ACCA-compliant Manual J (and S/D/T if needed) ready to submit.
Trusted by HVAC contractors and homeowners
"Quote in under an hour, report in two days, accepted by our county on the first submittal. That's it — that's the review."
HVAC contractor, Tampa FL
"Scott walked through the assumptions on a phone call before the report went out. Best $XXX I've spent on a project all year."
General contractor, Lexington KY
"We use LoadCalcs as our default for any new-construction Manual J. Zero permit kickbacks in 18 months."
Design-build firm, Phoenix AZ
Get a same-day quote on your load calculation.
Upload your plans, get a quote within hours, and receive a permit-ready report from a named, ACCA-certified designer.