Ring Measurements Guide

This guide explains the measurements displayed in the wedding band builder and how to use them to configure a ring that matches real world specifications.

Understanding Ring Size

Ring size tells you whether a ring will fit a specific finger. Different countries use different sizing standards, but they all describe the same physical measurement: the inner circumference (or equivalently, the inner diameter) of the ring.

Sizing Systems

System	How it works	Example
US	Numbered 3 through 13, including half sizes	US 7 = 0.68 inches inner diameter
EU	Inner circumference in millimeters	EU 54 = 17.3mm inner diameter
UK	Letter-based, from F through Z	UK N1/2 = 17.3mm inner diameter

The builder lets you switch between these systems using the US / EU / UK toggle buttons below the ring size slider.

How to Measure Ring Size

If you already know your ring size in one system, use the conversion table below. If not, the most accurate method is to visit a jeweler who can measure your finger with a ring mandrel.

For at-home estimation:

1. Wrap a thin strip of paper snugly around the finger
2. Mark where the paper overlaps
3. Measure the length in millimeters -- this is the circumference
4. Divide by 3.14159 to get the inner diameter
5. Find the closest match in the table below

Quick Conversion Table

US	EU	UK	Inner Diameter
4	47	H	14.9mm / 0.59in
5	49	J1/2	15.7mm / 0.62in
6	52	L1/2	16.5mm / 0.65in
7	54	N1/2	17.3mm / 0.68in
8	57	P1/2	18.2mm / 0.72in
9	59	R1/2	18.9mm / 0.74in
10	62	T1/2	19.8mm / 0.78in
11	65	V1/2	20.7mm / 0.81in
12	67	X1/2	21.5mm / 0.85in

For the complete table with all half sizes, see the Measurement System reference.

Ring Width

Ring width is the measurement across the top of the band, from one edge to the other. This is the most visible dimension and has the biggest impact on how the ring looks on the hand.

Width	Description
2--3mm	Narrow, delicate look
4--5mm	Classic medium width
6--8mm	Wide, bold appearance

The width slider shows the actual millimeter value on the tape ruler. The range depends on the selected profile shape -- different profiles have different base widths.

Ring Thickness

Ring thickness (also called height or gauge) is the measurement from the inside surface to the outside surface. Thicker rings feel more substantial but also use more metal.

Thickness	Description
1--1.5mm	Slim, lightweight
1.5--2mm	Standard comfort
2--3mm	Heavy, solid feel

The thickness slider works the same way as the width slider, showing actual mm values.

Diamond Stone Size

When diamonds are added to the band, the stone size control determines how large each individual diamond is.

Display Units

The stone size can be viewed in two units using the ct / mm toggle:

Millimeters -- the physical diameter of each stone across its widest point (the girdle).

Carats -- the weight unit used in the jewelry industry. Carat weight is approximated from the diameter using standard round brilliant proportions. The relationship is cubic: doubling the diameter roughly multiplies the carat weight by 8.

Diameter	Approx. Carats	Visual reference
0.5mm	0.001 ct	Grain-sized accent stones
1.0mm	0.004 ct	Small melee stones
1.5mm	0.012 ct	Standard melee
2.0mm	0.029 ct	Large melee

Stone Count

The number of diamonds placed on the ring depends on three factors:

• Diamond span -- what portion of the ring is covered (Full, 1/2, 1/3, 1/4, or Custom count)
• Diamond spacing -- the gap between stones (Touching, 1/2 Stone, Full Stone, Double)
• Stone size -- larger stones mean fewer fit in the same span

The actual stone count is computed automatically and displayed in the diamond panel.

Price Breakdown

The total price shown at the bottom of the builder is the sum of metal cost and diamond cost, multiplied by an optional markup.

Metal Price

Metal cost is based on the physical volume of the ring:

1. The ring's cross section area and radius determine the total metal volume
2. Volume is converted to weight using the metal's density (default: 18K gold at 15.5 g/cm3)
3. Weight is multiplied by the price per gram (default: $97/gram)

Changing the ring size, width, or thickness all affect the metal volume and therefore the price.

Diamond Price

Diamond cost is based on total carat weight:

1. Each stone's carat weight is computed from its diameter
2. Total carats = carat per stone x number of stones
3. Total diamond cost = total carats x price per carat (default: $1,200/ct for melee diamonds)

Changing stone size, count, span, or spacing all affect the diamond cost.

Reading the Price Bar

The price bar at the bottom shows a breakdown for each ring:

Her    3.2g 18K Gold ($310) + 12 dia 0.14ct ($168)    $478.00
His    4.1g 18K Gold ($398)                            $398.00
                                                Total  $876.00

Configuring Pricing Defaults

All pricing parameters can be customized through the API:

// Set pricing for a specific band
controller.setPricingParams({
  metalDensityGcm3: 21.4,       // Platinum density
  metalPricePerGram: 32,         // Platinum price per gram
  diamondPricePerCarat: 1500,    // Higher quality diamonds
  markupMultiplier: 1.3,         // 30% retail markup
}, 'her')

See the API Reference for full pricing parameter details, and the Measurement System page for technical implementation details.