Metal Weight Calculator
Calculate the weight of jewelry metal from dimensions and alloy type. Supports sheet, round wire, and tube shapes in silver, gold, copper, and brass.
About this calculator
Weight is volume times density, so this calculator's job is really just computing volume correctly for three different stock shapes before applying the alloy's density (sterling silver 10.49 g/cm³, 14k gold 13.07, 18k gold 15.58, copper 8.96, brass 8.5). Sheet stock is straightforward length × width × thickness. Round wire treats the "Width/Diameter" input as the wire's diameter and computes a cylinder: π × radius² × length. Tube is the trickiest — it subtracts an inner cylinder from an outer one, using the given outer diameter and wall thickness to derive the inner radius, and clamps that inner radius at zero so an oversized wall-thickness input can't produce a nonsensical negative area.
Once grams are known, the calculator also reports troy ounces (dividing by 31.1035, the troy ounce-to-gram conversion used throughout the precious metals trade) and pennyweight (troy ounces × 20, the traditional jewelry unit still used by casting houses and metal suppliers). This is the number you multiply by a live spot price to estimate material cost before you cut into sheet or draw wire, or the number a caster needs to know how much metal to melt for a piece. Keep in mind real bench stock has manufacturing tolerances — commercial sheet and wire can run a few percent off nominal dimensions — so use this figure to order material with confidence, then confirm the actual piece weight on a jewelry scale once your stock is in hand.
Inputs
Results
Weight
5.25 g
Troy Ounces
0.17 ozt
How to Use This Calculator
- Enter the dimensions of your piece (length, width, thickness in mm).
- Select the metal alloy (e.g., fine silver, 18k yellow gold, platinum) to apply its density.
- Review the calculated piece weight in grams and troy ounces.
- Use the weight to estimate material cost by multiplying by the current spot price.
- Adjust dimensions to hit a target weight or cost before ordering sheet metal.
How the result changes with Length
| Length | Weight | Troy Ounces |
|---|---|---|
| 25 | 2.62 g | 0.08 ozt |
| 38 | 3.99 g | 0.13 ozt |
| 75 | 7.87 g | 0.25 ozt |
| 125 | 13.11 g | 0.42 ozt |
What each input means
- Length
- Length of the metal piece in millimeters
- Width / Diameter
- Width for sheet, outer diameter for wire or tube
- Thickness / Wall
- Sheet thickness, or wall thickness for tube shapes
- Shape
- Cross-sectional shape of the metal stock.
- Metal Alloy
- Metal alloy determines the density used in the weight calculation.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersLength = 50, Width / Diameter = 10, Thickness / Wall = 1, Shape = 1 = 5 input(s) provided
- Calculate WeightWeight5.245 = 5.245
- Calculate Troy OuncesTroy Ounces0.169 = 0.169
- Calculate PennyweightPennyweight3.37 = 3.37
- Calculate VolumeVolume0.5 = 0.5
Engine last updated . Checked against 4 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does the Tube shape need both a width and a thickness input while Sheet and Wire only really use one dimension each?
A tube's volume is an outer cylinder minus an inner cylinder, so the calculator needs the outer diameter (from Width/Diameter) and the wall thickness (from Thickness/Wall) to derive the inner radius before subtracting one cross-sectional area from the other. Sheet only needs all three dimensions multiplied together, and round Wire only needs diameter and length, which is why those shapes read the same inputs differently.
What happens if I enter a wall thickness larger than the tube radius?
The calculator clamps the derived inner radius at zero before squaring it, so an oversized Thickness/Wall value can't produce a negative cross-sectional area. In that case the tube calculation effectively becomes a solid rod of the outer diameter, since there's no room left for a hollow core.
Why does 18k gold weigh more than 14k gold for the exact same dimensions?
Weight is volume times density, and 18k gold's alloy density (15.58 g/cm³) is higher than 14k gold's (13.07 g/cm³) because it contains a larger proportion of pure gold, which is denser than the copper and silver typically alloyed in. Since the calculator holds volume constant for a given shape and size, a higher karat value directly increases the resulting weight.
What's the difference between the Troy Ounces and Pennyweight outputs?
Both are derived from the grams figure: Troy Ounces divides grams by 31.1035 (the standard troy ounce-to-gram conversion used in precious metals trading), and Pennyweight multiplies troy ounces by 20, since a pennyweight is defined as 1/20th of a troy ounce. Pennyweight is the unit most jewelry casting houses and metal suppliers actually quote and price in.
Related Calculators
The questions that sit next to this one — chosen by subject, including calculators filed under a different category.
Casting Grain Calculator
Calculate how much casting grain (metal) you need for lost-wax casting based on wax model weight, metal density, and sprue/button allowance.
Jewelry MakingRing Blank Calculator
Calculate the metal strip length and width needed to fabricate a ring from US ring size, band width, and metal thickness.
AppraisalJewelry Appraisal Calculator
Estimate jewelry value including metal value, gemstone value, and craftsmanship premium for retail, insurance, and resale purposes.
Health InsuranceHealth Plan Comparison Calculator
Compare total annual costs across Bronze, Silver, Gold, and Platinum health insurance plans based on your expected medical spending.
Jewelry MakingChain Length Calculator
Calculate how much wire you need to make a chain of a given length. Accounts for link size, wire gauge, and link pattern complexity.
More in Crafts, Hobbies & Games.