About RenovationCalcs
RenovationCalcs is an independent project with one goal: to gather the everyday calculations homeowners, DIYers and buyers reach for across a whole renovation — room-by-room cost, material quantities, whole-house cost-per-square-foot, and budget & ROI — in one focused, free, no-signup hub with transparent formulas.
Who is behind it
Author and curator
To be clear about credentials: I am the author and curator of this site — not a licensed general contractor, architect, building inspector or financial advisor. What I bring is relevant and real: building deterministic online calculators (open-source Python projects) and engineering training, i.e. rigor on the arithmetic and geometry. That is what it takes to curate a hub of calculators: transparent method, correct formulas, cited conventions and worked examples.
Our principle: transparent & durably correct
Every calculator shows its formula, a worked example and a reference table. The tools rest only on timeless project math (area = length × width; quantity = area ÷ coverage × (1 + waste); cost = quantity × your unit price) and stable conventions (a 4×8 drywall sheet = 32 sq ft; paint ~350–400 sq ft/gal/coat; 10–15% tile and flooring waste). There are deliberately no material prices, labor rates, regional cost indexes or live loan rates — cost tools use the prices you enter — so the results stay valid over time.
Correctness is checked against known reference values (see the methodology and the numeric self-check). The formulas and their basis are documented under Sources & formulas. All results are planning estimates: get itemized written quotes from licensed contractors before committing; use licensed pros and pull permits for structural, electrical, plumbing and gas work; the financing and ROI tools are illustrative math on your figures, not financial advice, and added resale value is never guaranteed. Questions? Use the contact page.