Toolbelt - Trade Calculator

ZIezi Labs

Contains adsIn-app purchases

About this app

Toolbelt is a calculator app for working tradespeople. Electricians, plumbers, and carpenters — one app, every common job-site calc, backed by NEC, IPC, and IRC code references.

Built for the truck, the warehouse, and the rough-in.

WHAT'S INSIDE

Electrical
• Wire size by NEC 310.16 — ampacity, voltage drop, OCPD per 240.4(D)
• Conduit fill by Chapter 9 Table 1 — 40/31/53% rules, live overfill warning
• Voltage drop, 1φ / 3φ
• Box fill, 314.16
• Motor full-load amperes

Plumbing
• Pipe sizing by drainage fixture units (DFU)
• Vent sizing
• Water service sizing by Hunter's curve
• Slope and fall

Carpentry
• Concrete volume — slabs, footings, columns, steps, with bag counts
• Lumber framing — header span, joist span, rafter rise/run
• Stair calculator — rise, run, stringer
• Board feet

CODE REFERENCE
• 20+ NEC, IPC, IRC articles
• Offline. Searchable. No subscription required.

What’s new

Full metric support is here! Switch units in Settings, and every calculator now works in meters, centimeters, and kPa — with trade-standard defaults built in.

Also new:
• Manage saved estimates and link calculations to them
• Set a default trade so your go-to calculator opens first
• Clearer warning when an electrical load exceeds a 400A panel

Plus: saved jobs now display in their original units, and other fixes.