Calculators

Four free home improvement calculators. Each one exists because we needed it while writing a review, and because the arithmetic behind a buying decision is usually simpler than the marketing makes it look.

What they have in common#

They work without JavaScript. Each one renders a complete result server-side, from your inputs or from a worked example. JavaScript makes the result update live and keeps the URL shareable — it is not required for the tool to be useful.

They show their working. Every calculator page explains the equation it uses and where the constants come from. If you disagree with an assumption, you can see which one it is.

They set no cookies and load nothing external. No analytics, no fonts from a CDN, no third-party scripts. That is true of the whole site, and it is why these pages load in well under a second.

They are honest about defaults. The default values are real ones — a real product's battery capacity, a real state's groundwater temperature, a realistic patio. Not round numbers chosen to make a result look tidy.

Where each one came from#

The our tankless sizing calculator exists because every tankless heater is sold on a flow rate measured at the smallest temperature rise the manufacturer can justify, and because the one variable that decides your real capacity — the temperature of the water arriving at your house — is never in the sizing chart. It bundles a regional groundwater dataset so it can answer for your location rather than for Miami.

The our concrete bag calculator counts bags, which every concrete calculator does. What it also reports is how long each mixing method will take to get through them, because concrete starts setting in 30 to 45 minutes and a pour that takes nine hours is not a slower slab, it is a worse one.

The our UTV charging cost calculator exists because dividing a battery's capacity by its advertised range produces a consumption figure no working vehicle ever sees. It uses duty-cycle-based consumption figures instead, and compares against petrol at your own electricity rate.

The our gazebo size calculator catches the most common mistake in that category: sizing a structure to the furniture rather than to the furniture plus the space to walk around it. It draws the result to scale so the answer is visible rather than just numeric.