Hobby and Craft

  • Aquarium Volume Calculator
    Calculate your fish tank volume in US gallons and liters from length, width, and height in inches. Free, instant aquarium capacity calculator.
  • Essential Oil Dilution Calculator
    Calculate how many drops of essential oil to add to your carrier oil for a safe dilution percentage. Fast, accurate drops-per-ml blending tool.
  • Recipe Scaling Calculator
    Scale any recipe up or down. Enter an ingredient amount, original servings, and desired servings to get the new quantity instantly.
  • Scrabble Word Score Calculator
    Calculate the Scrabble score of any word using standard English letter values, double/triple word multipliers, letter bonuses, and the +50 bingo bonus.
  • Deck Board Calculator
    Free deck board calculator: enter deck size, board width, length and gap to find how many decking boards and screws you need, with a waste allowance.
  • Price per Round Calculator
    Calculate the price per round instantly. Enter total price and number of rounds to get cost per round and cost per 100 rounds for easy comparison.
  • 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.
  • Paint Quantity Calculator
    Calculate how many gallons of paint you need for your walls based on area, number of coats, and coverage per gallon. Fast, free paint estimator.
  • 3D Printer Buy vs Outsource Calculator
    Compare buying a 3D printer vs outsourcing parts. Get in-house cost, outsource cost, savings, and the exact break-even part quantity instantly.
  • Wallpaper Rolls Calculator
    Calculate how many wallpaper rolls you need for a room from perimeter, wall height, roll size and pattern repeat. Free, accurate, with rounding for waste.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.).

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