Madder
Fiber & maker crafts
Counted thread, quilt layout, yarn, knitting gauge, epoxy, and candle wax. Each tool shows the cut or the pour before you buy the materials.
Workshop tools
Calculators for the work, not the homework.
Precise tools for people who cut cloth, stack lumber, order a yard of gravel, pour a slab, load a bar, build an arrow, mix a dough, or price a listing. The answer is on the page when it loads. The formula is underneath it.
On the bench
13.42 ft
Common rafter · 6/12 · 24 ft span · no ridge deduction
Walnut
Woodworking & building
Board feet the way a yard bills them, a batten layout that fills the wall, and a rafter length you can mark on the stock.
Quarry
Landscape
How much to order for a pad, a bed, or a ring of stone. Yards, tons, and bags, with the density written next to the answer.
Slate
Concrete
Turn a slab, a column, or a set of steps into cubic yards, then into bags or asphalt tons.
Pitch
Construction
A stair that fits the total rise, and a roof pitch you can say three ways. The stringer cut and the rafter length are one link away.
Copper
Electrical
Which conductor carries the load, how many fit in the raceway, and how many volts you give up on the way there.
Axle
Automotive
Engine speed from a tire and a gear, compression from the chamber stack, and how a new wheel changes clearance.
Iron
Strength & sport
A rate-of-perceived-exertion chart you can load from, three powerlifting scores from the published coefficients, and a bowling sheet that knows a spare from a strike.
Sectional
Outdoors, aviation & archery
Arrow setup, the crosswind on a runway, a ski or snowboard length to start from, the energy a bullet carries, and the drop downrange.
Rye
Kitchen
Baker’s math for sourdough, and alcohol by volume from a hydrometer or a refractometer.
Ledger
Sellers
What a sale actually leaves, after the platform’s cut and the costs you already know. Rates are copied from the published fee pages and dated.
All 46 launch tools
cross stitch calculator · KD 0
Cross Stitch Calculator
Cross stitch fabric calculator. Enter the stitch count, fabric count, and margin to get the cloth size in inches or centimeters, with a cutting diagram.
quilt backing calculator · KD 0
Quilt Backing Calculator
Quilt backing calculator for yardage. Add overhang, piece 42 inch or 108 inch fabric the cheaper way, and round up to the next eighth of a yard.
quilt binding calculator · KD 0
Quilt Binding Calculator
Quilt binding calculator for straight-grain strips. Perimeter, join allowance, strip count, and yardage from the width of fabric.
resin calculator · KD 2
Resin Calculator
Epoxy resin calculator for rectangular pours, cylinders, and river channels. Volume in fluid ounces and millilitres, split by mix ratio.
candle wax calculator · KD 0
Candle Wax Calculator
Candle wax and fragrance calculator. Turn a water weight into wax and fragrance oil for soy, paraffin, coconut-soy, or beeswax.
board foot calculator · KD 2
Board Foot Calculator
Board feet calculator and lumber cost. Nominal or actual dimensions, quantity, price per board foot, and a waste allowance.
board and batten calculator · KD 1
Board and Batten Calculator
Board and batten calculator for an even layout. Board count, gap, batten overlap, and how many sticks to buy.
rafter calculator · KD 1
Rafter Calculator
Rafter length calculator. Common rafter from span, pitch, overhang, and ridge thickness, in feet-inches and with the pitch angle.
rpe calculator · KD 0
RPE Calculator
RPE calculator from the Reactive Training Systems chart. Turn reps and RPE into a percent of one-rep max, or a load into an estimated max.
dots calculator · KD 0
DOTS Calculator
DOTS, Wilks, Wilks-2, and IPF GL calculator. One total, one body weight, three published scoring formulas.
bowling score calculator · KD 6
Bowling Score Calculator
Bowling score calculator for ten-pin. Strikes, spares, and the tenth frame, with a running total.
arrow speed calculator · KD 4
Arrow Speed Calculator
Arrow speed, FOC, and kinetic energy calculator. Chronograph speed or an IBO estimate, plus front-of-center and foot-pounds.
crosswind calculator · KD 0
Crosswind Calculator
Crosswind component calculator. Runway, wind direction, and wind speed give the crosswind and the headwind or tailwind.
sourdough calculator · KD 1
Sourdough Calculator
Sourdough hydration calculator using baker’s percentages. Flour, water, starter, and salt, with the starter’s flour counted in the total.
etsy fee calculator · KD 5
Etsy Fee Calculator
Etsy fee and profit calculator. Listing fee, 6.5% transaction fee, payment processing, and optional offsite ads, with the date the rates were checked.
whatnot fee calculator · KD 0
Whatnot Fee Calculator
Whatnot fee calculator for US sellers. Tiered commission on the item price plus 2.9% + $0.30 processing, from the current help-center rate card.
quilt calculator · KD 9
Quilt Size Calculator
Quilt size calculator from a mattress preset, drop, and pillow tuck. Block layout and a suggested border, with links into the backing and binding tools.
quilt border calculator · KD 0
Quilt Border Calculator
Quilt border calculator for butted or mitered corners. Strip length, strip count, and yardage from a 1/4 inch seam.
half square triangle calculator · KD 0
Half Square Triangle Calculator
Half-square triangle and flying geese calculator. Two-, four-, and eight-at-a-time squares, plus the no-waste geese sizes.
fabric yardage calculator · KD 7
Fabric Yardage Calculator
Fabric yardage calculator. Piece size, quantity, and fabric width, with a cutting layout. Directional fabric stays in one orientation.
yarn calculator · KD 0
Blanket Yarn Calculator
Yarn calculator for a blanket. Craft Yarn Council weight, knit or crochet, and yards per skein. The yardage is an estimate.
knitting gauge calculator · KD 0
Knitting Gauge Calculator
Knitting gauge calculator. Compare your stitches and rows per 4 inches with the pattern, then cast on for a target width.
knitting decrease calculator · KD 2
Knitting Increase and Decrease Calculator
Evenly spaced knitting and crochet increases and decreases. Flat or in the round, with the remainder written out.
stair stringer calculator · KD 9
Stair Stringer Calculator
Stair stringer calculator. Risers, treads, run, stringer length, and throat, checked against IRC R311.7 riser and tread limits.
conduit fill calculator · KD 6
Conduit Fill Calculator
Conduit fill calculator for EMT, IMC, RMC, PVC, FMC, and LFMC. NEC Chapter 9 fill percents, with the minimum trade size.
voltage drop calculator · KD 11
Voltage Drop Calculator
Voltage drop calculator for copper or aluminum, single or three phase. The 3% and 5% figures are NEC informational notes.
ski length calculator · KD 3
Ski Size Calculator
Ski length calculator from height, weight, and ability. A chin-to-head heuristic from retailer fit charts, not a DIN setting.
snowboard size calculator · KD 0
Snowboard Size Calculator
Snowboard length calculator from height, weight, and riding style, with a wide-board flag at a US men’s 11 boot.
bullet energy calculator · KD 0
Bullet Energy Calculator
Bullet energy calculator. Foot-pounds, momentum, joules, and an optional Taylor KO factor, in grains or grams.
paypal fees calculator · KD 0
PayPal Fee Calculator
PayPal fee calculator for Checkout, Goods & Services, and cards. US rates from PayPal’s merchant fee page, including the gross-up.
stripe fee calculator · KD 1
Stripe Fee Calculator
Stripe fee calculator. Domestic cards at 2.9% + 30¢, international cards at an extra 1%, and the amount to charge so you net a target.
gravel calculator · KD 12
Gravel Calculator
Gravel calculator for tons and cubic yards. #57, pea gravel, crusher run, and river rock, with waste and a truckload count.
mulch calculator · KD 0
Mulch Calculator
Mulch calculator for bulk yards and 2 cubic foot bags. Depth, shape, and a waste percent.
soil calculator · KD 0
Soil Calculator
Topsoil calculator for bulk yards and bagged soil, with a settle allowance so the bed stays full.
stone calculator · KD 0
Stone Calculator
Stone and rock calculator for #57, river rock, flagstone, and crushed stone. Tons and cubic yards from a depth.
cubic yard calculator · KD 5
Cubic Yard Calculator
Cubic yard calculator for a rectangle, circle, triangle, or a known area. Feeds the gravel, concrete, asphalt, and soil tools.
concrete calculator · KD 58
Concrete Calculator
Concrete calculator for a slab, footing, column, or steps. Cubic yards, tons, and 40, 60, and 80 pound bag counts.
asphalt calculator · KD 0
Asphalt Calculator
Asphalt calculator in tons. Compacted hot mix at 145 lb/ft³, for a rectangle, circle, or triangle.
stair calculator · KD 0
Stair Calculator
Stair calculator for rise, run, riser height, and landings. Checked against IRC R311.7. The stringer cut is a separate tool.
roof pitch calculator · KD 0
Roof Pitch Calculator
Roof pitch calculator. Rise per 12, degrees, percent, and the rafter multiplier, from a rise and run or a measured angle.
ballistic calculator · KD 30
Ballistic Calculator
Ballistic calculator for drop, drift, velocity, and energy. Point-mass G1 and G7 drag. No reloading data.
gear ratio calculator · KD 0
Gear Ratio Calculator
Gear ratio calculator. Ring and pinion, and engine RPM at a road speed for a tire size and a transmission gear.
compression ratio calculator · KD 0
Compression Ratio Calculator
Compression ratio calculator. Static CR from bore, stroke, chamber, piston, gasket, and deck, plus dynamic CR at intake-valve closing.
wheel offset calculator · KD 0
Wheel Offset Calculator
Wheel offset calculator comparing an old and a new wheel. Width, offset, backspace, poke, and inner clearance.
wire size calculator · KD 0
Wire Size Calculator
Wire size calculator from NEC 2023 Table 310.16 at 75°C, plus a voltage-drop check. Verify with local code and an electrician.
abv calculator · KD 0
ABV Calculator
ABV calculator from original and final gravity, with the standard and alternate formulas and a refractometer correction.
A note on the old site
calculator.pro was a general calculator from 2013 to 2021. The links people made then — scientific, mortgage, BMI, decimal/binary/hex — now land on working versions of those tools. Ovulation and pregnancy URLs come back to this page. This site does not publish medical calculators.
Classic tools are listed quietly on purpose. The work is in the clusters above.
- 6/12 pitch · 24 ft span · 13.42 ft rafter
- 100 × 100 · 14-count · 13.14 in cloth
- 5 @ RPE 8 · of your max · 81.1%