Home & Construction Tools
Material quantities, coverage rates and running costs for real projects — the waste factor, the rounding up to whole bags, and the units that quietly differ between the label and the job.
Built for homeowners, DIYers, trade estimators. 44 tools published.
AC BTU Sizing
Dehumidifying needs sustained runtime. A unit that is too big hits the temperature target and shuts off before it has dried the air.
🏠ACH Airflow
Convert a room's volume and target air-change rate into ideal volumetric airflow.
🏠Attic Ventilation
Exhaust vents draw air from somewhere. With the soffits blocked, the nearest supply is the heated house below.
🏠Battery Window Planner
Simulate an editable hourly battery policy without connecting to equipment.
🏠Carpet Seam Planner
Use roll width and room orientation instead of treating carpet like square-area flooring.
🏠Circuit Load Diversity
Model simultaneous demand from entered load groups without claiming electrical-code compliance.
🏠Concrete Calculator
A 10 by 10 slab at four inches is 1.24 cubic yards. In 80 lb bags that is 56 of them, which is where ready-mix starts to look sensible.
🏠Contractor Quote Compare
Level itemized bids without pretending the cheapest stated total is the best contract.
🏠Deck Boards
Pressure-treated lumber is sold wet and shrinks across the width. Boards laid tight open up to the right gap on their own.
🏠Deck Joist Hardware
Derive hardware quantities from explicit joist connections without making a structural design claim.
🏠Dehumidifier Removal Cost
Relate rated power, runtime and collected water to moisture-removal cost.
🏠Drywall Calculator
Sheet length decides how many butt joints you have to hide, and butt joints are the seams that still show two years later.
🏠Drywall Compound
Estimate finishing compound from measured seam length instead of floor area alone.
🏠EV Charging Loss
Reconcile electricity drawn at the wall with energy reported as added to the battery.
🏠Firewood Cord
A full cord is 128 cubic feet. A face cord is the same height and length, one log deep — and nobody checks the depth.
🏠Generator Sizing
Motors do not all start at the same instant. Summing every starting watt buys twice the machine; ignoring them trips the first time the pump kicks in.
🏠Grass Seed
Rates run from 0.5 to 8 lb per thousand square feet depending on the species, and overseeding is half of new seeding. One number cannot cover that.
🏠Gravel Calculator
A four inch compacted base needs about a quarter more material than its finished volume. Order the finished figure and you run out.
🏠Grout Calculator
Grout fills joints, and small tiles have far more joint per square foot. The floor size is the least important input.
🏠Insulation Calc
R-value comes from trapped air, so compressing a batt throws the extra away. R-19 in a 3.5 inch bay gives R-10.6, below the R-13 made for it.
🏠Load Schedule Validator
Recalculate VA totals, phase sums and user-entered demand factors while keeping code decisions outside the tool.
🏠Lumens Calculator
Watts stopped meaning brightness when LEDs arrived. The number that sizes a room is lumens per square foot, and it varies four to one.
🏠Multi-EV Charge Planner
Allocate hourly charging by deadline without exceeding a user-entered site cap.
🏠Paint Calculator
The first coat is partly absorbed and the second is not, so multiplying by the number of coats overestimates. This splits them.
🏠Paver Calculator
The pavers are the visible cost. The compacted base underneath is the bigger pile, the longer day, and the reason it stays flat.
🏠Rainwater Calc
Shingles cover the slope, but rain falls straight down. The catchment is the footprint, so a steep roof collects no more than a flat one.
🏠Renovation Timeline
Turn user-defined tasks and predecessors into an auditable critical-path draft.
🏠Retaining Wall
Round a wall layout to whole blocks and show the backfill volume separately.
🏠Running Cost
A thermostat means the compressor runs about a third of the time, so the usual watts-times-hours sum overstates the cost by roughly three times.
🏠Sheet Cut Optimizer
Build a reproducible first-fit cut plan with kerf, rotation and waste reporting.
🏠Shingle Calculator
A 1,600 sq ft footprint at 6/12 pitch is 1,789 sq ft of roof. At 12/12 it is 2,263. Measuring from the ground is only the first step.
🏠Solar Clipping Loss
Compare available AC-equivalent power with the inverter ceiling over an entered interval.
🏠Solar Export Credit
Separate self-consumed energy value from exported-energy credit.
🏠Solar Self-Consumption
Separate direct solar use, battery-supplied solar, export and grid import for one period.
🏠Solar Shading Loss
Apply monthly shade exposure and system recovery to an unshaded forecast.
🏠Stair Stringer
Solve a whole-number riser layout before marking a stringer board.
🏠Standby Power Cost
Scale a measured low-power mode across devices, hours, days and your own electricity price.
🏠Stud Calculator
Corners, T-intersections, kings, jacks and cripples are most of the difference between the formula and the pile of lumber you actually need.
🏠Three-Phase Energy
Convert line voltage, current and power factor into input power and running cost.
🏠Tile Calculator
Ten per cent is right for a straight layout and short for a diagonal. The same floor needs 132 or 138 square feet depending on the pattern.
🏠TOU Appliance Scheduler
Compare hourly starts while respecting run length, availability and a concurrency cap.
🏠Voltage Drop
A 20 amp circuit 100 feet away drops 6.6% on 12 AWG. Sizing by amps alone is how a long run ends up dim and a pump motor dies young.
🏠Wallpaper Rolls
Paper is hung in full-height drops, and every drop on a patterned paper is cut to a whole number of repeats. That is where the extra rolls come from.
🏠Water Heater Size
Only 70 per cent of a tank is usable, and recovery rate makes up the rest. First-hour rating is the number that decides whether you run out.