Although it may seem like it's an arbitrary measure depending on how well you dip your fingers into the salt bowl a "pinch" is actually supposed to be a specific measure of 1/16th of a teaspoon. But because it is rather small, a tiny bit more or less usually won't be too much of an issue in the larger recipe. Usually.
a pinch is less than a tsp. it's just a very small amount
A pinch
That is about 14 teaspoons
3 teaspoons equal 15 gm.
There is approximately 0.3 teaspoons in 1.5 milliliters.
That is 768 teaspoons.
756.8 teaspoons in a gallon.
That is 10 teaspoons.
That is approximately 72 teaspoons.
That is approximately 3.5 teaspoons.
That is 44 teaspoons.
At 6 tsp per ounce you get 10.14 tsp for 1.69 ounces. This is a smidge* over 10 & 1/8 tsp (10.125). *note: 1/8 tsp is considered the smallest amount you can measure, equal to a pinch. Smidge could be considered a dash.