About CalcNest

CalcNest is a small, independent project with one goal: free calculators that show their work.

Why we show the formula

Most online calculators give you a number and nothing else. That's fine until the number looks wrong — then you're stuck. Every CalcNest tool publishes the exact formula it uses, the default assumptions (standard bag sizes, coverage per gallon, material densities, seeding rates), and notes on when those assumptions break down. You should never have to trust a black box for a home project.

How we keep it free

CalcNest is supported by unobtrusive display advertising. There are no accounts, no paywalls, no email harvesting, and no selling of data. The calculators run entirely in your browser — the numbers you type never leave your device.

Accuracy

Each calculator is built around published industry rules of thumb (for example, paint coverage of about 350 square feet per gallon, or mulch at 2–4 inches deep) and cross-checked against manufacturer guidance. Where real-world values vary — gravel density, wax blends, grass cultivars — we say so on the page and give you the assumption we used so you can adjust.

How a calculator gets published

Every tool follows the same path. We start from a published rule or standard — a formula from a clinical guideline, a coverage rate from a paint or mulch manufacturer, a bag yield printed on a concrete mix. We implement it as a small self-contained page, then check it by recalculating worked examples by hand and against a second unit system (imperial and metric) before it goes live. If a number cannot be pinned down — gravel density, wax blend shrinkage, seed germination — the page publishes the value we assume and tells you how to substitute your own.

Corrections

Calculators are checked, not infallible. If a formula, a default value or a unit conversion looks wrong to you, send the page URL and the numbers you entered through the contact form. Confirmed errors are fixed on the page, and the affected calculator is re-checked end to end rather than patched in one spot.

What CalcNest is not

These are estimating tools for everyday planning. They are not medical, legal, structural or financial advice, and they do not replace a doctor, an engineer or a supplier's own take-off. For anything where being wrong is expensive or dangerous — dosing, structural loads, electrical work — treat the result as a starting point and have it checked by a professional.

Suggestions welcome

Missing a calculator? Found a bug? Contact us — reader requests are prioritized.