An imperial fluid ounce is 1/160 of an imperial gallon.
Imperial fluid ounces to Teaspoons Converter — imp fl oz to tsp
Convert Imperial fluid ounce (imp fl oz) to Teaspoon (tsp) using the exact conversion factor (1 imperial fluid ounce = 5.764559642 teaspoon). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Imperial fluid ounces to Teaspoons 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.
A US teaspoon is one third of a US tablespoon.
Result = input x 2.84130625e-5 / 4.92892159e-6.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Imperial fluid ounces to Teaspoons
Imperial fluid ounce and Teaspoon 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. Imperial fluid ounce is typically associated with united Kingdom (historically; less common in current UK retail than metric units), while Teaspoon is typically associated with united States (cooking and recipe measurement).
Formula
teaspoons = imperial fluid ounces × 5.76455964242
This factor comes from each unit's defined relationship to the category's base unit: 1 imperial fluid ounce equals 0.0000284130625 base units, and 1 teaspoon equals 0.00000492892159375 base units, so dividing one by the other gives the direct imperial fluid ounce-to-teaspoon factor of 5.76455964242.
Simple example
1 imp fl oz × 5.764559642 = 5.764559642 tsp
1 imperial fluid ounce = 5.764559642 teaspoons.
Real-world example
10 imp fl oz × 5.764559642 = 57.64559642 tsp
10 imperial fluid ounces = 57.64559642 teaspoons.
Conversion table
| Imperial fluid ounce (imp fl oz) | Teaspoon (tsp) |
|---|---|
| 1 imp fl oz | 5.764559642 tsp |
| 5 imp fl oz | 28.82279821 tsp |
| 10 imp fl oz | 57.64559642 tsp |
| 25 imp fl oz | 144.1139911 tsp |
| 50 imp fl oz | 288.2279821 tsp |
| 100 imp fl oz | 576.4559642 tsp |
Reverse conversion: Teaspoon to Imperial fluid ounce
5.764559642 tsp × 0.1734737885 = 0.9999999999 imp fl oz
5.764559642 teaspoons = 0.9999999999 imperial fluid ounces.
imperial fluid ounces = teaspoons × 0.173473788464
For a page dedicated to this direction, see Teaspoon to Imperial fluid ounce.
Imperial fluid ounce vs. Teaspoon
| Aspect | Imperial fluid ounce | Teaspoon |
|---|---|---|
| Family | UK/imperial customary unit | US customary unit |
| Typical use | UK/Commonwealth beverage measurement in historical or specialized contexts | US recipe and cooking measurement for small quantities |
| Where it's used | United Kingdom (historically; less common in current UK retail than metric units) | United States (cooking and recipe measurement) |
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.
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
Imperial fluid ounce — sources
- UK Weights and Measures Act 1824 — Basis for the imperial fluid ounce via the imperial gallon.
Teaspoon — sources
- NIST Handbook 44, Appendix C — General tables of units including the US teaspoon definition.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many teaspoons are in 1 imperial fluid ounce?
1 imperial fluid ounce equals 5.764559642 teaspoons, using the exact defined conversion factor rather than an estimate.
How do I convert imperial fluid ounce to teaspoon?
Multiply the imperial fluid ounce value by 5.764559642. The converter above does this instantly to whatever precision you set.
How do I convert teaspoon back to imperial fluid ounce?
Use the reverse factor: 1 teaspoon equals 0.1734737885 imperial fluid ounces. You can also use the swap control in the converter above to flip the direction instantly.
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.
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.
Is the imperial fluid ounce to teaspoon conversion exact?
Yes. The US teaspoon is exactly 4.92892159375 milliliters — 1/3 of a US tablespoon and 1/48 of a US cup. 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 imperial fluid ounce still used today?
United Kingdom (historically; less common in current UK retail than metric units)