• 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.).
  • 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.