Metric System Teaching/Learning Resources

Speaking at the MidSchool Math conference a couple of weeks ago got me thinking about how I first got involved with the metric system as an adult. It was two hobbies really: beading and working with essential oils. Both forced me to work with metric units: millimeters and milliliters, respectively.

How crazy is this? Bead sizes in mm and strand in inches.

How crazy is this? Bead sizes in mm and strand in inches. Image from Fire Mountain Gems

Beading wasn’t too bad since most bead sizes were expressed solely in millimeters but I had my daughter buy me a caliper so I could start to envision the various sizes. The oils were more difficult because some books and websites used metric units while others used customary units and that made price comparisons difficult.

Using what works beautifully

Of course, once I started mixing oils it became readily apparent that working with decimals was FAR easier for scaling up and down and I abandoned customary units for this work entirely. That left me primed for events that followed: I learned about our sorry history with the metric system and started to shoot video again at work. That intersection of events eventually led me to take on this documentary project.

I will say that while learning the metric system, you should avoid conversions as much as possible. The more you work in the metric system the easier it is. You most likely already have rulers and tape measures with metric units. Just get used to using them in place of those pesky customary units.

Metric system resources for teachers and others

There are lots of resources on the metric system out on the web. (As well as “metric system,” another search term is “International System of Units” [or “SI” as it is referred to by most of the world] or Le Système international d’unités” in French. The quotation marks tell the search engine to look for that exact term, BTW).

Here are a few handy sites to get you rolling:

National Institute for Standards and Technology. It has free resources specifically for teaching the metric system. Here are a couple of things my contact there sent me

Information on how to teach the metric system from the U.S. Metric Association

Don’t know this site (Math is Fun) very well but seems to have some good resources for teaching kids.

I came across this site while researching for this post. The “mystery canisters” further down on the page sounds like fun.

The National Council of Teachers of Mathematics position on teaching the metric system in schools.

Using the metric system in the kitchen

A question that came up during the session was how to convert U.S. customary unit recipes into metric units. Since few people currently use scales in their kitchen now (mandatory with the metric system since grams are used—not volume) it’s not surprising that issue came up.

I offered she could make the recipe the usual way making note of the millimeters and grams as she went along and it wouldn’t be any more variable than any other time she’s made it. (Grandma’s treasured layer cake, for instance.)

However, I found a site with easy-to-use conversion tables for converting your old recipes: “The Metric Kitchen.” I suggest this approach instead.

Need a new recipe? Just start out with it in metric units.

For instance, the wildly wonderful site allows you to access ingredients in metric units from the get-go:


To view metric versions of recipes on, click on “Change servings” and choose metric


The Metric Maven also has a metric cookbook that I know he’d like to see get some more use.

“Math and the Metric System: Using What’s Easy”

I’ve had requests for the overheads from Math and the Metric System (pdf). I am willing to share them here but please understand that you’re missing the narration that goes along with them and I do reserve the rights to work that went into them. That said, I hope you find them informative.

I’ll have another post next week. I have several different subjects in mind but I can’t decide which one to write about next.

Of course, if you have a question, please send it to me ( and I’ll see what I can do about collecting them and providing answers in this blog.



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