Home improvement · DIY
Calculators that show their work.
Free tools for home improvement projects. Every formula public, every source cited. No signup, no email capture, no affiliate agenda.
By project type
Browse by category
Paint + walls
3Gallons, rolls, and sheets
Masonry
5Concrete, brick, rebar, asphalt
Flooring + kitchen
8Tile, hardwood, cabinets, countertops
Landscaping
9Deck, fence, mulch, gravel, sod
Roofing + exterior
6Shingles, siding, gutters, snow load
HVAC + plumbing
4Heat pump, BTU, water heater, drain
Electrical + solar
3Panels, wire gauge, extension cords
Lumber + framing
5Board feet, stairs, studs, windows
Buying guides
Decisions that need real math
Vinyl vs fiber cement siding
30-year TCO math, fire ratings, and the repaint cycle nobody talks about
Composite vs PT vs cedar decking
20-year cost breakdown — pressure-treated is actually the most expensive option
Heat pump vs furnace + AC
Climate-zone-by-zone operating costs with federal tax credit math
How it works
Three things every calculator does
Shows the formula
Every calculator displays the exact formula it used — not just the answer. You see every input, every intermediate step, and every rounding rule. If the answer looks wrong, you can trace it.
Cites the source
Coverage rates, sizing factors, and code requirements come from manufacturer data sheets, building codes (IRC, IPC, NEC), and industry references (ACCA, NADRA, APA). Sources are linked on every page.
Rounds to buyable units
You can't buy 2.67 gallons of paint. Results are rounded up to the nearest practical purchase quantity — with the raw number shown alongside so you can make your own call.
Why Tallyard
What we don't do
No email gates
You never need to sign up, log in, or hand over your email to use a calculator. The tools are free and unrestricted.
No lead generation
We don't sell your zip code to contractors. No "get 3 free quotes" forms, no contractor matching, no data brokering.
No affiliate bias
Guide recommendations reflect what the numbers say, not which link pays the highest commission. We don't run affiliate links.
No hidden formulas
If we can't show you how we got the number, we don't publish the calculator. Transparency isn't a feature — it's the whole point.
Start with the math
Pick a calculator, enter your measurements, and get an answer you can verify. No account required.