About 000345
An independent toolkit for squaring, measuring and estimating construction work.
What we do
000345 publishes free calculators and guides for layout and estimating: squaring corners with the 3-4-5 rule, sizing concrete, laying out stairs and rafters, and counting the materials for decks, fences, floors and walls. Every tool works in imperial and metric units and shows the formula it uses.
Why the name
Every build starts from a zero point. From that corner you measure three units one way, four the other, and check for five on the diagonal. 0-0-0-3-4-5 is that sequence, and it describes what we want every visitor to leave with: a corner, and a project, that starts square.
How we work
- Show the math. Every calculator page explains the formula and includes a worked example you can check by hand.
- Plain language. We write for someone holding a tape measure, not a textbook.
- Safety first. Structural work depends on local codes, soils and loads that a calculator cannot see. We say so on every relevant page.
- Clear money. The site is funded by advertising, sponsorships, reader support and contractor referrals. Sponsors never change our numbers. See How we calculate.
Contact
Questions, corrections and partnership ideas are welcome. Use the contact page. Last reviewed October 2026.