Practical tools, clear methods
OpenTools
Free calculators for everyday work — estimate materials, calculate ages and dates, and see the method behind every result.
Construction & Home Improvement
Material estimates and practical planning tools for projects at home.
- Concrete CalculatorEstimate concrete volume, cubic yards, and 80 lb bag quantity for a rectangular slab.
- Tile CalculatorEstimate tile order coverage, approximate tiles, and cartons for a rectangular surface.
- Gravel CalculatorEstimate gravel volume, supplier-density-based weight, and optional material cost for a rectangular area.
- Paver Base CalculatorEstimate base aggregate and bedding material volumes separately for a rectangular paver project.
- Paint CalculatorEstimate paint quantity from room dimensions or known area, coats, and label coverage.
- Drywall CalculatorEstimate whole drywall sheets from coverage area, selected panel size, and an optional allowance.
- Flooring CalculatorEstimate flooring order area, whole cartons, and optional material-only cost.
- Deck Board CalculatorEstimate deck boards from configurable board dimensions, gaps, and allowance.
- Fence Material CalculatorEstimate panels or pickets and posts from measured fence runs and product dimensions.
- Post Hole Concrete CalculatorEstimate concrete volume and whole bags for a post-hole geometry you enter.
- Mulch CalculatorEstimate bulk cubic yards or whole bags of mulch from bed dimensions and installed depth.
- Roofing CalculatorEstimate simple gable roof area, roofing squares, and whole shingle bundles.
- Insulation CalculatorEstimate insulation coverage and whole packages using product label coverage.
- Stair CalculatorPlan equal risers, treads, total run, and stringer geometry using limits you enter.
- Board Foot CalculatorCalculate lumber board feet, allowance, and optional material-only cost.
- Countertop CalculatorEstimate countertop square footage, the number of stone slabs you need, and an installed cost range for granite, quartz, or marble.
- Topsoil CalculatorEstimate cubic yards of topsoil, the number of bags to buy, and a bulk cost range from your bed area and depth.
- Drywall Mud CalculatorEstimate joint compound in gallons and whole buckets by drywall area and GA-214 finish level, with a bucket cost range.
- Sod CalculatorEstimate how much sod you need: lawn area in square feet, slabs or rolls, pallets, and a material cost range.
- Overseeding CalculatorEstimate how much grass seed you need to overseed: seed in lbs, whole bags, and a cost range by grass type.
- Grass Seed CalculatorEstimate how much grass seed you need for a new lawn: seed in lbs, whole bags, and a cost range by grass type.
Date & Time
Date, time, and calendar calculations for everyday planning.