Home & DIY

Make smarter home decisions

Calculators, decision guides, and planners for home improvement, DIY, and auto

Free home improvement and DIY calculators for projects and running costs — paint and concrete coverage, the right TV size for your room, electricity and fuel costs, and gas mileage. The decision guides cover the judgment calls: whether it's time for a new car, whether switching to LED actually pays off, and how to budget a paint project. Measure first, decide second.

DIY & Home Projects Toolkit

“How much do I need?” — answered before you load the cart

Eight material estimators covering the projects that start with a tape measure: concrete and paint, mulch and gravel for the yard, flooring, tile, and drywall for inside, roofing for the top. Every tool includes the waste factor the supplier assumes you forgot.

🧱Concrete 🎨Paint 🍂Mulch 🪨Gravel 🪵Flooring 🔲Tile 🏗️Drywall 🏠Roofing

🧱 DIY Concrete Project Checklist 🎨 Interior Paint Budget Guide

Coverage rates worth memorizing

Paint: ≈ 350–400 sq ft per gallon per coat

Concrete: 80 lb bag = 0.60 cu ft · 1 cu yd = 27 cu ft

Drywall: 4×8 sheet = 32 sq ft · 4×12 = 48 sq ft

Roofing: 1 square = 100 sq ft = 3 bundles (most brands)

The same numbers every calculator above uses — supplier labels override.

Read the math first: How much concrete you need · How much paint to buy · Electricity cost guides

Energy & Running Costs

What your home costs while you aren’t looking

Appliance running costs, LED payback, the vampire load of “off” devices, and the home-charging vs gas-pump math for the car. The same electricity-rate bill powers every tool here.

⚡Electricity Cost 💡LED Savings 👻Standby Power 🔌EV Charging Cost ⛽Fuel Cost 🚗Gas Mileage

💡 Should You Switch to LED?

Energy quick hits

60W bulb → 9W LED: saves ≈ $9/year per 3-hour-a-day bulb

Cable box on 24/7 (18W): ≈ $27/year doing nothing

Whole-home standby: ≈ 5–10% of your electricity bill

EV home vs public charging: usually 2–4× cheaper per mile at home

At the US average rate of $0.17/kWh — plug in your own bill for exact numbers.

Read the math first: How to calculate electricity cost · Gas cost for a road trip