Smart calculators that show their work.
32 free, fast calculators with the formula, a worked example and sources on every page.
Home & Construction
- Asphalt CalculatorTons and cubic yards of hot mix asphalt for a driveway, path or patch from area and compacted thickness.
- Board Foot CalculatorBoard feet and cost for any list of lumber, from 4/4 hardwood to 2×4 studs.
- Brick CalculatorBricks and mortar for a wall or veneer, using Brick Industry Association quantities for each brick size.
- Concrete Slab CalculatorCubic yards, 40/60/80 lb bags and total cost of concrete for a slab, patio or pad.
- Cubic Yard CalculatorTurn length, width and depth into cubic yards for any bulk material, with waste and cost.
- Deck Board CalculatorNumber of deck boards, linear feet and screws for a wood or composite deck, with board gaps.
- Drywall CalculatorSheets of 4×8, 4×10 or 4×12 drywall for a room’s walls and ceiling, with waste and cost.
- Fence CalculatorPosts, rails, pickets and post-hole concrete for a wood privacy or picket fence of any length.
- Flooring CalculatorBoxes of laminate, vinyl plank, engineered or hardwood flooring for a room, with waste and underlayment.
- Grass Seed CalculatorPounds and bags of grass seed for a new lawn or overseeding, using extension seeding rates by species.
- Gravel CalculatorHow many tons and cubic yards of gravel or crushed stone you need, with compaction and cost.
- Lawn Fertilizer CalculatorHow many pounds of a fertilizer to apply for a target rate of nitrogen, from the N-P-K on the bag.
- Mulch CalculatorBags or cubic yards of mulch for any bed or tree ring, at the depth horticulturists recommend.
- Paint CalculatorGallons and quarts of paint for a room’s walls and ceiling, minus doors and windows, for any number of coats.
- Paver CalculatorNumber of pavers for a patio or walkway, plus the crushed-stone base and bedding sand underneath.
- Pea Gravel CalculatorHow much pea gravel you need for a path, patio or play area, in cubic yards, tons and 0.5 ft³ bags.
- Retaining Wall Block CalculatorBlocks, caps, base gravel and drainage stone for a segmental retaining wall or garden wall.
- Roof Pitch CalculatorConvert rise and run into roof pitch (x/12), angle in degrees, slope percent and roof squares.
- Sand CalculatorCubic yards, tons and bags of sand for paver bedding, sandboxes, leveling and fill.
- Sod CalculatorPallets, rolls and cost of sod for a new lawn, from lawn size, roll size and pallet coverage.
- Square Footage CalculatorAdd up rectangles, triangles and circles to get total square feet, square metres, square yards and acres.
- Stair Stringer CalculatorNumber of risers, riser height, treads, total run and stringer length, checked against IRC stair limits.
- Tile CalculatorNumber of tiles and boxes for a floor, wall or backsplash, with waste for cuts and pattern.
- Topsoil CalculatorCubic yards, tons or bags of topsoil to level a lawn, build a bed or fill a raised garden.
Education & Grades
- College GPA CalculatorSemester GPA from letter grades and credit hours on the 4.0 scale, with quality points and pass/fail handling.
- Cumulative GPA CalculatorCombine semester GPAs and credits into a cumulative GPA, and see the GPA you need next term to hit a target.
- Final Grade CalculatorThe score you need on your final exam to reach the course grade you want, with an A–D table.
- High School GPA CalculatorSemester and cumulative unweighted GPA on the 4.0 scale, with or without plus/minus grades.
- Reading Time CalculatorHow long it takes to read a book, article or speech, from word count or pages, using research-based reading speeds.
- Test Curve CalculatorSee your curved test score under five common curving methods, from square-root curves to shifting the average.
- Test Grade CalculatorTurn the number wrong (or right) into a percentage and letter grade, plus a full grading chart.
- Weighted GPA CalculatorWeighted and unweighted GPA side by side, with honors and AP/IB bonuses you can adjust.