I would. At that scale, it really doesn’t matter all that much. I use whatever spoon is at hand (though I have proper measuring spoons for some reason), and it works out fine. Cooking and even baking isn’t nearly as precise as some people make it out to be.
Anyone else use your hand, like I do? I can put some salt/sugar/paprika/whatever into my hand and eyeball pretty accurately a teaspoon/tablespoon/fraction of either.
Doing some of my own research here, I am finding that even in France, the home of metric, almost all the cuillères à mesurer are dual-labeled (e.g. 1 tsp 5 ml), with a few exceptions, as here:
But before anyone, by some unlikely mischance, buys the above for €11.90, let me mention that you can get it on Ebay for US$0.99 
Someone may notice that the above is also dual labeled, just with milliliters and grams, the grams being what that much water weighs.
It looks impossible to do more than guess, at the answer to the thread title question, without having an inside source spilling measuring spoon industry secrets.
Yep. And for liquids I guess while pouring how much is a teaspoon, how much a tablespoon. Literally did that a few minutes ago for a marinade. It’s not that hard to get in the ballpark.
I can’t believe nobody has stated the obvious. Our measuring spoons are not really metric.
If they were metric, you’d have baby spoons. Ten baby spoons to a Tablespoon. Instead, we get a teaspoon? Where did that come from? And, three teaspoons to a Tablespoon? Maybe they could have tried to meet metric half-way and decided five teaspoons to a Tablespoon?
No, the whole measuring ingredients by volume is flawed to begin with. They should go by weight. For liquids or solids, using a spoon is the most inaccurate way of measuring volume there is. It needs to be narrower at the top than the bottom to get accuracy. If accuracy isn’t that important, well then, it really doesn’t matter.
Thank you, Kayaker!
My wife can be making a stir-fry, and when I come out to wash the dishes there are four measuring spoons, a 1/4 C measuring cup, a 1/3 C measuring cup, and a 1 C measuring cup waiting to be washed. For all that’s good and holy, it’s just a stir-fry! And who uses a 1 C and doesn’t re-use it for approximating 1/3 C?
But it’s one of the reasons I love her.
I totally understand and agree.
No one measures spice, or salt, or baking soda, or vanilla extract by weight for home cooking quantities. Home scales aren’t nearly as accurate as spoons for those quantities. Heck, “by eye” is more accurate.
(Ask the woman who used her home cooking scale to taper off tea in preparation for fasting on Yom kippur. Towards the end, it just wasn’t accurate enough, and i eyeballed the amount of loose tea instead.)
And spoons are super convenient.
I once compared all my measuring volumes against each other. 3 teaspoons to a tablespoon, two tablespoons to an ounce, … I went from the ⅛ teaspoon spoons up to the gallon measuring cup. They were all pretty good except one tablespoon which was too small. I threw that one away. And for kicks, i measured our “eating” spoons. The teaspoon is close enough that i use it for a measuring spoon sometimes. The tablespoon is far less than 3 teaspoons. But it’s a good size to shovel cereal and soup into my mouth. So i kept those. 
Do i always measure precisely with those spoons? No. If the recipe calls for a teaspoon of vanilla, i just pour in a little more than a teaspoon. (Unless I’m making whipped cream, where i don’t like too pronounced a vanilla taste.) But i like being able to be precise when i want to reproduce something. Oh, and I’m precise with the baking soda.
If you’re using a spoon to shovel cereal and soup into your mouth, it’s not a tablespoon. Tablespoons are for serving, not for eating.
No, those are serving spoons.
That’s interesting, because some in my household growing up ate using tablespoons and others used teaspoons. We had larger spoons for serving food. I wasn’t aware that others reserved them only for serving.
We have little bitty spoons that we inherited. I think they were intended to serve salt. I sometimes use them as tools, but never bring them to the table.
Then we have teaspoons, which we mostly use for tea, actually. Or serving honey. And tablespoons that we use for soup, cereal, and sometimes stew or whatever. And some funky soup spoons with a very wide shallow bowl (also inherited) that i mostly use for defatting broth, since the angle is good for that. And a variety of serving spoons which came in sets with the serving forks and pie servers.
No, what I’m saying is that those larger-than-teaspoons that some folks eat with aren’t tablespoons. I’m not sure what the proper name for them is: My family calls them soup spoons, but that also often refers to a spoon with a circular bowl.
Dinner spoons? At any rate, I have 15mL spoons (I measured) that I use to eat cereal and soup with. Teaspoons are way too small. I have some of those intermediary spoons you’re talking about, I think, but I use the 15mL ones.
Wikipedia has pictures of various spoons:
The volume measure tablespoon is a reasonable size to eat with, fwiw.
If you visit me and eat at my table, the proper name for them is tablespoons. Although Oneida calls them “dinner spoons”.
The idea that the larger spoon in a flatware place setting is for serving and not eating is honestly so foreign to me that I’ve been Googling. Tiffany flatware sets include teaspoons and dessert spoons. Oneida flatware sets include teaspoons and dinner spoons. Cambridge Silversmiths flatware sets includes teaspoons and “dinner/soup spoons.” Christofle flatware sets includes teaspoons and tablespoons. Zwilling flatware sets includes teaspoons and soup spoons (though not the bowl type but instead the usual oval).
Again, that’s not the spoon I’m referring to.
OK, here’s a link to a photo of a flatware place setting. The description says it includes “Dinner Fork; Dinner Knife; Salad Fork; Teaspoon; Dinner Spoon.” Is the larger spoon there what you’re thinking of?
Heh, I have some silver itty bitty coke spoons, and some stainless steel teeny spoons for dabbing. Salt, huh?
My grandmother actually set her formal table with tiny little salt containers that had tiny little spoons in them. But i suppose you might find other uses for them … Honestly, i mostly use them for fishing marrow out of bones.