Hobby and Craft

  • Seed Starting Date Calculator
    Find exactly when to start seeds indoors. Enter your last frost date and the weeks-before figure from your seed packet to get the sowing date.
  • Raised Garden Bed Soil Calculator
    Calculate how much soil your raised garden bed needs in cubic feet, cubic yards, and number of bags. Free, fast, and supports multiple beds.
  • Firewood Cord Calculator
    Calculate how many cords of firewood you have from your stack's length, width and height in feet. Free, instant firewood cord calculator.
  • Epoxy Mix Ratio Calculator
    Calculate exact resin and hardener amounts for any epoxy mix ratio by volume or weight. Enter total amount and your part ratio to get precise quantities.
  • 3D Printing Time & Cost Calculator
    Estimate the true cost of a 3D print: filament material cost plus electricity from print time and printer wattage. Free, instant, currency-agnostic.
  • 3D Printer Filament Length-to-Weight Calculator
    Convert 3D printer filament length to weight in grams. Enter length, diameter (1.75mm/2.85mm) and material density to estimate spool usage instantly.
  • Pendulum Clock Period Calculator
    Calculate a simple pendulum's period from its length, or find the length needed for a target period. Adjustable gravity for any location.
  • Pottery Glaze Batch Calculator
    Scale any pottery glaze recipe to your batch size. Enter percentages and dry weight to get exact gram amounts per ingredient plus water needed.
  • Yarn Substitution Calculator
    Swapping yarn in a knitting or crochet pattern? Calculate how many skeins of your new yarn you need based on total yardage. Free and instant.
  • Gift Wrap Paper Calculator
    Calculate the exact wrapping paper sheet size needed for any gift box. Enter box length, width, height and overlap to get paper width, length and area.
  • Sock Knitting Calculator
    Calculate how many stitches to cast on for hand-knit socks from your foot circumference, gauge, and negative ease. Get a snug, well-fitting sock.
  • Furniture Paint Coverage Calculator
    Calculate how many liters of chalk or furniture paint you need based on surface area, number of coats, and paint coverage per liter.
  • Coin Roll Calculator
    Calculate how many coin rolls you can make and their total value. Supports US pennies, nickels, dimes, quarters, half dollars and dollar coins.
  • Knitting Increase/Decrease Calculator
    Evenly space knitting increases or decreases across a row. Enter current and target stitch counts to get the interval, count of changes, and leftovers.
  • Reef Tank Salt Mix Calculator
    Calculate how much reef salt mix to add to your water to hit a target salinity (ppt). Enter water volume, target salinity, and your salt's dose rate.
  • RC Car Gear Ratio Calculator
    Calculate your RC car's final drive ratio (FDR) from spur gear, pinion gear, and internal transmission ratio. Free, instant pinion/spur gearing tool.
  • Model Rocket Altitude Calculator
    Estimate your model rocket's apogee altitude from a measured baseline distance and elevation angle using simple trigonometry. Get results in meters and feet.
  • Thrust-to-Weight Ratio Calculator (Drone/RC)
    Calculate the thrust-to-weight ratio (TWR) of your FPV drone or RC aircraft from motor thrust, motor count, and all-up weight to gauge performance.
  • Aquarium Heater Wattage Calculator
    Calculate the right aquarium heater wattage from tank size, desired temperature rise, and watts per gallon. Quick, accurate sizing for fish tanks.
  • 3D Print Time Estimator
    Estimate 3D print time from model height, layer height and average time per layer. Get total layers, hours, minutes and seconds instantly.
  • LED Strip Length, LED Count & Power Draw Calculator
    Calculate LED strip power draw, total LED count and current. Enter strip length, LEDs per meter, watts per LED and voltage to size your power supply.
  • Vinyl / HTV Material Calculator
    Calculate how much vinyl or heat transfer vinyl (HTV) you need for your cuts. Enter design size, quantity, roll width and waste to get length in inches and feet.
  • Scale Model Dimension Calculator
    Convert real-life dimensions to scale model size for dioramas, miniatures and figures. Enter the real size and scale ratio (1:35, 1:87, etc.).
  • Golden Ratio Design Calculator
    Split any total length into golden-ratio proportions (φ ≈ 1.618). Get the larger and smaller segments instantly for design, layout and typography.

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