A US teaspoon is one third of a US tablespoon.
Teaspoons to Imperial fluid ounces Converter — tsp to imp fl oz
Convert Teaspoon (tsp) to Imperial fluid ounce (imp fl oz) using the exact conversion factor (1 teaspoon = 0.1734737885 imperial fluid ounce). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Teaspoons to Imperial fluid ounces converter
Converter
Volume Converter
Convert metric, US customary, imperial, cooking, dry, and industrial volume units.
Context values
Some unit families need one extra value for a physically accurate result.
An imperial fluid ounce is 1/160 of an imperial gallon.
Result = input x 4.92892159e-6 / 2.84130625e-5.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Teaspoons to Imperial fluid ounces
Teaspoon and Imperial fluid ounce appear side by side at fuel pumps and on beverage labels, since the US measures liquids in gallons while most of the world uses liters. Teaspoon is typically associated with united States (cooking and recipe measurement), while Imperial fluid ounce is typically associated with united Kingdom (historically; less common in current UK retail than metric units).
Formula
imperial fluid ounces = teaspoons × 0.173473788464
This factor comes from each unit's defined relationship to the category's base unit: 1 teaspoon equals 0.00000492892159375 base units, and 1 imperial fluid ounce equals 0.0000284130625 base units, so dividing one by the other gives the direct teaspoon-to-imperial fluid ounce factor of 0.173473788464.
Simple example
1 tsp × 0.1734737885 = 0.1734737885 imp fl oz
1 teaspoon = 0.1734737885 imperial fluid ounces.
Real-world example
10 tsp × 0.1734737885 = 1.734737885 imp fl oz
10 teaspoons = 1.734737885 imperial fluid ounces.
Conversion table
| Teaspoon (tsp) | Imperial fluid ounce (imp fl oz) |
|---|---|
| 1 tsp | 0.1734737885 imp fl oz |
| 5 tsp | 0.8673689423 imp fl oz |
| 10 tsp | 1.734737885 imp fl oz |
| 25 tsp | 4.336844712 imp fl oz |
| 50 tsp | 8.673689423 imp fl oz |
| 100 tsp | 17.34737885 imp fl oz |
Reverse conversion: Imperial fluid ounce to Teaspoon
0.1734737885 imp fl oz × 5.764559642 = 1 tsp
0.1734737885 imperial fluid ounces = 1 teaspoons.
teaspoons = imperial fluid ounces × 5.76455964242
For a page dedicated to this direction, see Imperial fluid ounce to Teaspoon.
Teaspoon vs. Imperial fluid ounce
| Aspect | Teaspoon | Imperial fluid ounce |
|---|---|---|
| Family | US customary unit | UK/imperial customary unit |
| Typical use | US recipe and cooking measurement for small quantities | UK/Commonwealth beverage measurement in historical or specialized contexts |
| Where it's used | United States (cooking and recipe measurement) | United Kingdom (historically; less common in current UK retail than metric units) |
Understanding the Teaspoon
Teaspoon (tsp) measures volume. The US teaspoon is exactly 4.92892159375 milliliters — 1/3 of a US tablespoon and 1/48 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 Teaspoon today
- US recipe and cooking measurement for small quantities
- Medication dosing instructions in the US
- Baking measurement alongside the tablespoon and cup
Understanding the Imperial fluid ounce
Imperial fluid ounce (imp fl oz) measures volume. The imperial fluid ounce is 1/160 of an imperial gallon: exactly 28.4130625 milliliters — slightly smaller than the US fluid ounce despite the larger imperial gallon, because it divides that gallon into more parts. It is classified as a UK/imperial customary unit.
Where it's used: United Kingdom (historically; less common in current UK retail than metric units)
Imperial fluid ounce vs. US fluid ounce. Confusingly, the imperial fluid ounce (28.41 mL) is slightly smaller than the US fluid ounce (29.57 mL), even though the imperial gallon is larger overall — because the imperial gallon is divided into 160 fluid ounces rather than the US gallon's 128.
Uses of the Imperial fluid ounce today
- UK/Commonwealth beverage measurement in historical or specialized contexts
History of the Imperial fluid ounce
The imperial fluid ounce follows from Britain's 1824 imperial gallon, divided into 160 parts rather than the 128 used in the US system, producing its counterintuitively smaller size relative to the US fluid ounce.
Historical origin. Imperial fluid ounce was not the invention of a single named person; it developed through the process described above.
Teaspoon — sources
- NIST Handbook 44, Appendix C — General tables of units including the US teaspoon definition.
Imperial fluid ounce — sources
- UK Weights and Measures Act 1824 — Basis for the imperial fluid ounce via the imperial gallon.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many imperial fluid ounces are in 1 teaspoon?
1 teaspoon equals 0.1734737885 imperial fluid ounces, using the exact defined conversion factor rather than an estimate.
How do I convert teaspoon to imperial fluid ounce?
Multiply the teaspoon value by 0.1734737885. The converter above does this instantly to whatever precision you set.
How do I convert imperial fluid ounce back to teaspoon?
Use the reverse factor: 1 imperial fluid ounce equals 5.764559642 teaspoons. You can also use the swap control in the converter above to flip the direction instantly.
What is a teaspoon?
Teaspoon (tsp) measures volume. The US teaspoon is exactly 4.92892159375 milliliters — 1/3 of a US tablespoon and 1/48 of a US cup. It is classified as a US customary unit.
What is a imperial fluid ounce?
Imperial fluid ounce (imp fl oz) measures volume. The imperial fluid ounce is 1/160 of an imperial gallon: exactly 28.4130625 milliliters — slightly smaller than the US fluid ounce despite the larger imperial gallon, because it divides that gallon into more parts. It is classified as a UK/imperial customary unit.
Is the teaspoon to imperial fluid ounce conversion exact?
Yes. The imperial fluid ounce is 1/160 of an imperial gallon: exactly 28.4130625 milliliters — slightly smaller than the US fluid ounce despite the larger imperial gallon, because it divides that gallon into more parts. 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 imperial fluid ounce vs. us fluid ounce?
Confusingly, the imperial fluid ounce (28.41 mL) is slightly smaller than the US fluid ounce (29.57 mL), even though the imperial gallon is larger overall — because the imperial gallon is divided into 160 fluid ounces rather than the US gallon's 128.
Where is the teaspoon still used today?
United States (cooking and recipe measurement)