Hobby and Craft

  • Telescope Magnification Calculator
    Calculate telescope magnification from objective and eyepiece focal lengths. Also finds exit pupil. Free, instant, and easy to use.
  • Camera Depth of Field Calculator
    Calculate camera depth of field from focal length, f-number, subject distance and circle of confusion. Get near/far focus limits and total DoF.
  • Camera Angle of View Calculator
    Calculate a camera lens horizontal, vertical and diagonal angle of view in degrees from focal length and sensor size, plus the 35mm-equivalent focal length.
  • Camera Field of View (Shooting Range) Calculator
    Calculate a camera's angle of view and the physical shooting range (captured width, height and area) from lens focal length, sensor size and subject distance.
  • Quilt Calculator
    Free quilt calculator: find how many blocks fit your quilt and the backing fabric area needed. Enter quilt size and block size to plan your project.
  • Pleated Skirt Fabric Calculator
    Calculate the fabric length and number of pleats needed for a knife or box pleated skirt from your waist, pleat width, and seam allowance.
  • Cross-stitch Fabric Calculator
    Calculate cross-stitch design size and how much Aida or linen fabric to cut from stitch count, fabric count, and margins. Inches & cm.
  • Flash Guide Number (GN) Aperture / F-Number Calculator
    Calculate the optimal lens aperture (f-number) for flash photography from guide number(s), subject distance and ISO. Supports up to 3 combined flash units.
  • Flash Photography Distance Calculator
    Calculate correct flash-to-subject distance from Guide Number (GN), f-number and ISO. Supports combining 1-3 strobes. Universal photographic physics.
  • Optimal Megapixels for Print Paper Size Calculator
    Find how many camera megapixels you need to print any paper size cleanly at 200, 300 and 400 dpi. Supports L, 2L, A and JIS B photo paper sizes.
  • 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.
  • Helium Balloon Lift Calculator
    Find how many helium balloons it takes to lift an object. Enter weight and balloon size to get lift per balloon and total balloons needed.
  • Archery Draw Length Calculator
    Find your archery draw length from your arm span using the wingspan ÷ 2.5 method. Enter your wingspan in inches for an instant draw length estimate.
  • Pizza Size Calculator
    Compare two pizza sizes by area. See how much more food a larger pizza gives and which size is the better deal — diameter to area in seconds.
  • Priming Sugar Calculator
    Calculate how much corn sugar (dextrose) to add for bottle-conditioning beer. Enter volume, target CO₂ and temperature to get grams of priming sugar.
  • Self-Rising Flour Calculator
    Make your own self-rising flour. Enter cups of all-purpose flour to get the exact baking powder and salt to add. Fast, accurate DIY substitute.
  • Pancake Recipe Calculator
    Free pancake recipe calculator that scales flour, milk, eggs and more by servings and pancakes per person. Get exact ingredient amounts instantly.
  • Cake Serving Calculator
    Estimate how many slices a round cake serves from its diameter and slice size. Free cake serving calculator for parties, weddings and events.
  • Baker's Percentage Calculator
    Convert baker's percentages into exact ingredient weights. Enter flour weight and hydration, salt and yeast percentages to scale any bread recipe.
  • SO₂ Wine Calculator
    Calculate how much potassium metabisulfite (KMS) to add to your wine to reach a target free SO₂ level, based on volume and current SO₂ in ppm.
  • Fresh to Dry Herb Conversion Calculator
    Convert fresh herbs to dried in any recipe. Uses the standard 3:1 ratio — divide fresh by 3 to get the equivalent dried amount. Free and instant.
  • Silver Melt Value Calculator
    Calculate the silver melt value of coins, bars and scrap from weight, fineness and spot price. Supports grams, troy & avoirdupois ounces and kilograms.
  • Scrap Silver Value Calculator
    Calculate the value of scrap silver from weight, fineness, spot price, and dealer payout. Get melt value and expected payout in seconds.
  • Scrap Gold Value Calculator
    Estimate the value of scrap gold by weight, karat purity, current spot price and dealer payout percentage. Get full melt value and per-gram price.

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