Free Online Calculators for Jewelry Makers

Jewelers like to be precise. Actually, jewelers have to be precise because the quality depends heavily on precision. Even if customers can't explain it, they feel that something is off when a piece has small inaccuracies. Even though I'm a hobbyist, I always strive for better quality. So, as a software developer by trade, I decided to put my skills to good use and build a set of free calculators for jewelers at tools.coldbrewjewelry.com.

At the time of writing this post, I have been on a long break from making jewelry for various reasons. But I haven't lost my interest, and I'm longing to go back to it when circumstances change. I'd be happy to keep airing new tutorials.

Meanwhile, I found another way to help fellow hobbyists and, hopefully, even professionals.

Every time I make a new piece, it involves calculations. Many professional jewelers judge by eye where a newbie would turn to formulas. Some things require a combination of both—you calculate and then tweak the results based on your experience.

Some calculations are easier than others. For the ring blanks, we all have our tables. But when it comes to making a collet or a round tapered bezel, traditionally, you don't even calculate. You draw.

Especially as a hobbyist, I don't use specific calculations very often. So, I need to reach out to grab a book to look it up. And I do love books on jewelry, and I have a few. And I don't always remember which one has the right calculations or a template.

Long story short, I implemented the Cold Brew Jewelry Tools—a set of calculators you can use right from your phone or computer, for free. Here's what's available so far.

Ring Blank Length Calculator

The ring blank length calculator can replace your usual ring size table. It covers different sizing systems. There are a few approaches to calculating the length of a ring blank, and you may find that different sources show different lengths for the same ring size. Some sources recommend manually accounting for different metal thicknesses. Others advise adding extra length to account for metal loss during filing. In my version, I combined a geometric approach with a reasonable 1.5 mm overhead to account for filing and soldering. There's even a little diagram as a reminder that shows an extra length has been added to the blank.

Metal Weight & Cost Calculator

The metal weight calculator lets you calculate the weight of different metals for basic stock shapes: sheet, tube, and wire. The calculation is based on the metal's actual volume and density. You can also add the price per gram to calculate the total cost of your material.

Bezel Strip Length Calculator

The bezel strip calculator gives you the strip length for different stone shapes. Keep in mind that for the oval shape, the calculation uses an approximation that works better with calibrated stones. I also added a custom overlap that defaults to 1.5 mm to account for sawing and filing. This usually works best for beginners, but may be overkill for experienced jewelers. Remember, you always want a snug fit for the bezel. If it's too tight, you can stretch it on a mandrel. But if it's too loose, you'd need to re-solder it.

Tapered Bezel (Collet) Template Generator

This is the most interesting one. When I first tried tapered bezels with a forming block, I started with a self-made tube bezel. The results weren't great, to be honest. While it can work if you pick the width correctly, it's way more consistent if you start with a proper tapered shape. But for me, it was always tricky to follow the geometric approach by manually drawing the unwrapped collet shape.

That's why I created a math-based collet template generator. It creates a shape you can print, glue to the metal, and use your piercing saw on. Make sure to saw outside of the template line to allow for filing.

IMPORTANT: When you print, make sure to select 100% scale in the printer settings. Different browsers and operating systems tend to scale the image to fit the paper size automatically. So please, double-check on that. 100% scale should work correctly with the standard Letter and A4 paper sizes.

Wire Length Calculator

As a beginner, you might be following a tutorial that provides the exact amounts of supplies. But when you switch to your personal projects, you have to calculate them yourself. And as a hobbyist, you probably don't have a huge stock rotation for one-off projects.

In the wire length calculator, I provide a few multipliers based on the project type. More sophisticated designs may use other multipliers, which are often learned from experience. This calculator is simple and geared more towards beginners. As you get more experience, you'll find a sweet spot for the projects you're working on. But when you're starting with wire wrapping techniques, it may come in handy.

Jump Ring Wire Length Calculator

When I only need one jump ring, I don't bother calculating the wire length. I always have some wire at hand for such one-offs. But when I'm planning a project, like a bracelet, for example, I'd like to know how much wire I actually need. A good example could be a heavy bracelet with a combination of different jump rings, such as 12- and 22-gauge, which can be a significant money investment. That's especially important for beginners and hobbyists. You can try the jump ring calculator here.

Ring Size Conversion Chart

When I'm reading articles or blog posts, they come from around the world. And jewelers in the UK, for example, reference ring sizes using their system. So, a quick reference chart becomes handy in this case. Over time, you probably get more familiar with a specific subset of sizes that you're usually working with. But having a handy ring size conversion table doesn't hurt. You can also print one for the size systems that you need.

What's next

The Cold Brew Jewelry Tools site is a living project. I already have a set of features and additional tools planned, including a wire gauge reference chart and an alloy mixing calculator. But my goal is to make these tools genuinely useful for the jewelry-making community. I added a little form to provide feedback or request a feature. You can find it right here. I read every submission, and if you leave your email, I'll do my best to reply.

If you find a specific calculator useful, please share the link to it with fellow jewelers—direct links to individual tools work great. And you can always find the full set at tools.coldbrewjewelry.com.