A US tablespoon is half a US fluid ounce.
Tablespoons to Gallons Converter — tbsp to gal
Convert Tablespoon (tbsp) to Gallon (gal) using the exact conversion factor (1 tablespoon = 0.00390625 gallon). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Tablespoons to Gallons converter
Converter
Cooking Converter
Convert cooking volume and mass units used in recipes and nutrition workflows.
Context values
Some unit families need one extra value for a physically accurate result.
A US liquid gallon is exactly 3.785411784 liters.
Result = input x 1.47867648e-5 / 0.003785411784.
Volume units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Tablespoons to Gallons
Tablespoon and Gallon both show up in recipes, and converting between them matters whenever a recipe from one country's cookbook needs to be followed with another country's measuring tools. Tablespoon is typically associated with united States (cooking and recipe measurement), while Gallon is typically associated with united States (fuel, beverage, and liquid measurement).
Formula
gallons = tablespoons × 0.00390625
This factor comes from each unit's defined relationship to the category's base unit: 1 tablespoon equals 0.0000147867647813 base units, and 1 gallon equals 0.003785411784 base units, so dividing one by the other gives the direct tablespoon-to-gallon factor of 0.00390625.
Simple example
1 tbsp × 0.00390625 = 0.00390625 gal
1 tablespoon = 0.00390625 gallons.
Real-world example
2 tbsp × 0.00390625 = 0.0078125 gal
2 tablespoons = 0.0078125 gallons.
Conversion table
| Tablespoon (tbsp) | Gallon (gal) |
|---|---|
| 0.25 tbsp | 0.0009765625 gal |
| 0.5 tbsp | 0.001953125 gal |
| 1 tbsp | 0.00390625 gal |
| 2 tbsp | 0.0078125 gal |
| 4 tbsp | 0.015625 gal |
| 8 tbsp | 0.03125 gal |
Reverse conversion: Gallon to Tablespoon
0.00390625 gal × 256 = 1 tbsp
0.00390625 gallons = 1 tablespoon.
tablespoons = gallons × 256
For a page dedicated to this direction, see Gallon to Tablespoon.
Tablespoon vs. Gallon
| Aspect | Tablespoon | Gallon |
|---|---|---|
| Family | US customary unit | US customary unit |
| Typical use | US recipe and cooking measurement | Fuel pump and vehicle fuel-economy measurement in the US |
| Where it's used | United States (cooking and recipe measurement) | United States (fuel, beverage, and liquid measurement) |
Understanding the Tablespoon
Tablespoon (tbsp) measures volume. The US tablespoon is exactly 14.78676478125 milliliters — 3 US teaspoons, or 1/16 of a US cup. It is classified as a US customary unit.
Where it's used: United States (cooking and recipe measurement)
Uses of the Tablespoon today
- US recipe and cooking measurement
- Nutrition labeling serving sizes in the US
- Medication dosing instructions in the US
Understanding the Gallon
Gallon (gal) measures volume. The US liquid gallon is defined as exactly 231 cubic inches, equal to 3.785411784 liters. It is classified as a US customary unit.
Where it's used: United States (fuel, beverage, and liquid measurement)
US gallon vs. imperial gallon. The US liquid gallon (3.785411784 L) and the British imperial gallon (4.54609 L) are different units with the same name; always confirm which one a source is using.
Uses of the Gallon today
- Fuel pump and vehicle fuel-economy measurement in the US
- Beverage and liquid product packaging in the US
- Cooking and recipe measurement in US customary units
History of the Gallon
The US gallon descends from the English wine gallon of 231 cubic inches, a standard used for measuring wine in medieval and early modern England, which the American colonies inherited and retained even after England moved to a different imperial gallon in 1824.
England's 1824 Weights and Measures Act replaced the old wine gallon with a new imperial gallon (based on 10 pounds of water), but the US kept the older 231-cubic-inch definition — which is why the US gallon (3.785 L) and the imperial gallon (4.546 L) differ by about 20% today.
Historical origin. Gallon was not the invention of a single named person; it developed through the process described above.
Tablespoon — sources
- NIST Handbook 44, Appendix C — General tables of units including the US tablespoon definition.
Gallon — sources
- NIST Handbook 44, Appendix C — General tables of units of measurement, including the US gallon definition.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many gallons are in 1 tablespoon?
1 tablespoon equals 0.00390625 gallons, using the exact defined conversion factor rather than an estimate.
How do I convert tablespoon to gallon?
Multiply the tablespoon value by 0.00390625. The converter above does this instantly to whatever precision you set.
How do I convert gallon back to tablespoon?
Use the reverse factor: 1 gallon equals 256 tablespoons. You can also use the swap control in the converter above to flip the direction instantly.
What is a tablespoon?
Tablespoon (tbsp) measures volume. The US tablespoon is exactly 14.78676478125 milliliters — 3 US teaspoons, or 1/16 of a US cup. It is classified as a US customary unit.
What is a gallon?
Gallon (gal) measures volume. The US liquid gallon is defined as exactly 231 cubic inches, equal to 3.785411784 liters. It is classified as a US customary unit.
Is the tablespoon to gallon conversion exact?
Yes. The US liquid gallon is defined as exactly 231 cubic inches, equal to 3.785411784 liters. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between us gallon vs. imperial gallon?
The US liquid gallon (3.785411784 L) and the British imperial gallon (4.54609 L) are different units with the same name; always confirm which one a source is using.
Where is the tablespoon still used today?
United States (cooking and recipe measurement)