Imperial teaspoon to US liquid gallon

One imperial teaspoon equals approximately 5.919 mL — slightly larger than the US teaspoon (4.929 mL) and the metric teaspoon (5 mL).

An imperial teaspoon is approximately 5.92 mL; a metric teaspoon is exactly 5 mL. The metric teaspoon is now standard in UK cooking, medicine, and pharmacology.

The imperial teaspoon is obsolete in modern UK, Australian, and Canadian cooking, which all use the 5 mL metric teaspoon. It may appear in cookbooks published before the 1970s metrication period.

A culinary pinch — the amount you can hold between thumb and forefinger — is roughly 0.3–0.5 mL, or about 1/16 of a teaspoon. Professional recipe developers have measured this and found surprising consistency across people: the human fingertip geometry constrains how much fine powder you can grip. A "dash" (liquid) is about 0.6 mL, and a "smidgen" is half a pinch (~0.15 mL). These folksy terms survive in recipes because they map to real, repeatable volumes — within the tolerance that salt and spice measurements actually require.

The WHO recommended the 5 mL metric teaspoon for medication dosing in the 1970s to eliminate ambiguity between imperial (5.92 mL), US (4.93 mL), and other teaspoon sizes. A calibrated 5 mL oral syringe is now the recommended tool for all liquid medicines.

US fuel infrastructure — pumps, tax law, pipeline contracts, and consumer expectations — is built around the gallon. Federal and state fuel taxes are levied per gallon; EPA fuel economy standards use miles per gallon; and consumers benchmark prices against a gallon reference ("$3 a gallon"). Switching to liters would require reprogramming every pump, rewriting tax code, and re-educating 330 million people who compare prices by the gallon. Canada made the switch in the 1970s during a broader metrication push, but the US never had the political will for a comprehensive changeover.

The US gallon (3.785 L) is based on the Queen Anne wine gallon of 1707 (231 cubic inches). The UK imperial gallon (4.546 L) was defined in 1824 as the volume of 10 pounds of water. The two systems diverged after US independence.

To convert: L/100km = 235.2 ÷ MPG (US). A car achieving 30 MPG uses about 7.8 L/100km. UK MPG values are always higher than US MPG for the same car because the imperial gallon is larger.

Recommended daily water intake is about 2–3 liters (roughly 0.5–0.8 US gallons). The commonly cited "8 glasses a day" ≈ 64 fl oz ≈ 0.5 gallons ≈ 1.9 liters.

Most US passenger cars have fuel tanks of 10–20 gallons (38–76 liters). Compact cars are typically 10–13 gallons; mid-size cars 14–17 gallons; SUVs and trucks 18–36 gallons.