Every calculator shows its math
You shouldn't trust a calculator that won't show its work. Tap "Show Formula" on any SiteCalc calculator and you'll see the exact equation, the variables, and where the formula comes from. NEC tables, IRC spans, IPC fixture units. All cited.
The math, not a black box
The concrete slab calculator doesn't just say "4.2 cubic yards." It shows you: length x width x depth / 27, with your actual numbers plugged in. You can check it with a pencil. You can explain it to a client. You can hand it to an inspector who wants to see your work.
This is how construction math should work. Transparent. Verifiable.
Code references built in
The wire sizing calculator cites NEC 310.16 for ampacity tables. The stair calculator references IRC R311.7 for riser/tread requirements. The drain slope calculator points to IPC 704.1. The gas pipe calculator pulls from IFGC tables.
You'll see the specific code section next to the formula. Not buried in a help page. Right there, next to the math.
85 formulas, all visible
This applies to every calculator in the app. Concrete, framing, roofing, electrical, plumbing, HVAC, paint, tile, landscape, general. No hidden logic. No proprietary algorithms. Standard trade formulas, implemented correctly, shown openly.
If you find a formula you disagree with, you'll know exactly what it's doing and can decide for yourself.
Related features
- Code References -- NEC, IRC, IPC, and IFGC citations next to every result.
- PDF Export -- formulas and code references appear in your exported documents.
Read more: How to Size Wire for a Circuit (NEC 310.16)
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Check the math yourself. Every formula, every code reference.