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Free Construction & Trade Calculators

Estimate materials.
Save money.
Build right.

Fast, accurate calculators for construction, electrical, landscaping, and surface projects - built on DOT and NEC reference data.

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Free Calculators
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Trade Categories
NEC
Code Tables
DOT
Reference Data

CalcShed is a free library of 0+ construction and trade calculators for concrete, electrical, landscaping, and surface materials. Every calculator shows its formula and source standards (ACI, NEC, ASTM, DOT data) so you can verify the math, not just take a number.

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Why CalcShed
Reference-First Data
Calculations are built from published tables and standard unit conversions. We cite assumptions and show formulas instead of hand-waving.
Built for Mobile
Fast inputs, clear outputs, and no external libraries. The calculators are designed to work well on-site, not just on a desktop.
Transparent Methodology
We document formulas and assumptions so you can sanity-check results. See our Methodology and Data Sources pages for the details.