These units of measure are listed from smallest to largest. Bartending books often list units of measure larger than the largest unit given here and omit the smaller units. While it is fun to think of Jeroboams of Champagne, I feel that mixology can make more use of the scruple than the Jeroboam. For that reason, my list includes the small units and stops with the gallon.
Note: I understand that many modern sources define the jigger as being the amount of 1-½ fl-oz. But, I prefer the original amount as defined by all sources before prohibition as being 2 fl-oz. For historic references on this, see this post.
| Traditional Unit (U.S.A.) | Type of Measure & Metric Equivalent | Other Equivalents & Notes | |
| Smidgeon (smdg.) | volume | 0.15625 ml. | ½ pinch, ¼ dsh. or ⅛ scsp. |
| Pinch | volume | 0.3125 ml. | 2 smdg., ½ dsh. or ⅛ bsp. |
| Dash (dsh.) | volume | 0.625 ml. | 2 pinches, ½ scsp., ¼ bsp. or ⅛ tsp. |
| Scruple (scr.) | weight | 1.16667 grams | 1/24 oz. |
| Scruple-spoon (scsp.) | volume | 1.25 ml. | 2 dsh., ½ bsp., ¼ tsp. 1/12 tbsp. or 1/24 fl-oz. |
| Bar-spoon (bsp.) | volume | 2.5 ml. | 2 scsp. or ½ tsp. |
| Dram | weight | 3.5 grams | 3 scr. or ⅛ oz. |
| Fluid-dram | volume | 3.75 ml. | 3 scsp., ¾ tsp., ¼ tbsp. or ⅛ fl-oz. |
| Tea-spoon (tsp.) | volume | 5 ml. | 2 bsp., ½ dsp., ⅓ tbsp. or ⅙ fl-oz. |
| Dessert-spoon (dsp.) | volume | 10 ml. | 2 tsp. or ⅓ fl-oz. |
| Table-spoon (tbsp.) | volume | 15 ml. | 3 tsp., ½ fl-oz. or ½ pony |
| Ounce (oz.)* | weight | 28 grams | 1/16 pound |
| Pony/fluid-ounce (fl-oz.) | volume | 30 ml. | 2 tbsp., ½ jigger or ¼ gill |
| Shot | volume | 45 ml. | 1-½ fl-oz. or ¾ jigger |
| Jigger/Wine-glass | volume | 60 ml. | 2 fl-oz. or ½ gill |
| Hooker | volume | 75 ml. | 2-½ fl-oz. or 1-¼ jiggers |
| Snit | volume | 90 ml. | 3 fl-oz., 1-½ jiggers or ¾ gill |
| Gill | volume | 120 ml. | 4 fl-oz., 2 jiggers or ½ cup |
| Split/Tea-cup | volume | 180 ml. | 6 fl-oz. or 3 jiggers |
| Cup | volume | 240 ml. | 8 fl-oz., 4 jiggers or 2 gills |
| Pint | volume | 480 ml. | 16 fl-oz., 4 gills or 2 cups |
| Fifth | volume | 750 ml. | 25 fl-oz. |
| Traditional Fifth | volume | 768 ml. | 25-⅗ fl-oz. or 1/5 gal. |
| Quart (qt.) | volume | 960 ml. | 32 fl-oz., 4 cups or 2 pints |
| Pottle | volume | 1920 ml. | 64 fl-oz., 2 qt. or ½ gal. |
| Gallon (gal.) | volume | 3840 ml. | 128 fl-oz., 4 qt. or 2 pottles |
*When bartenders say, “ounce,” they mean, “fluid-ounce.”
For how the cup, the gill and the jigger are used as basic portions in traditional, American mixology, see this post.
elementalmixology.blog 
Thanks for this!