Teaspoons to ml Calculator
Convert teaspoons to millilitres for cooking and medicine. UK teaspoon = 5 ml exactly. Includes tablespoon conversions and a UK vs US comparison.
Quick Reference: tsp & tbsp to ml
| Measure | ml (UK) | Tablespoons | ml (tbsp UK) |
|---|---|---|---|
| ½ tsp | 2.5 ml | ½ tbsp | 7.5 ml |
| 1 tsp | 5 ml | 1 tbsp | 15 ml |
| 2 tsp | 10 ml | 2 tbsp | 30 ml |
| 3 tsp | 15 ml | 3 tbsp | 45 ml |
| 4 tsp | 20 ml | 4 tbsp | 60 ml |
| 5 tsp | 25 ml | 5 tbsp | 75 ml |
| 6 tsp | 30 ml | 6 tbsp | 90 ml |
| 10 tsp | 50 ml | 10 tbsp | 150 ml |
UK Teaspoon: The 5 ml Standard Explained
In the United Kingdom, the teaspoon is defined as exactly 5 millilitres. This seems simple, but the standardisation of this measurement has important historical roots, safety implications, and practical consequences that reach from your kitchen into your medicine cabinet and beyond.
History: How the UK Standardised the Teaspoon
The teaspoon as a unit of measure has a surprisingly complex history. In Victorian Britain, "a teaspoonful" was a vague measure — roughly the volume of one of the small silver teaspoons used in polite society for stirring tea. These spoons varied considerably by manufacturer, region, and era.
In the early 20th century, as pharmacological science advanced and standard dosing became critical, the medical profession needed a precise measure. The British Pharmacopoeia eventually adopted 5 ml as the standard teaspoon measure for medicine. This was chosen partly because it was close to the typical silver teaspoon volume and partly because it divided conveniently into 15 ml (one tablespoon) and other useful quantities.
Today, the NHS actively discourages the use of kitchen teaspoons for medicine. Since 2012, NICE (the National Institute for Health and Care Excellence) has recommended that oral liquid medicines for children be administered using oral syringes or graduated medicine spoons rather than household spoons. This is because the volume error from a random kitchen teaspoon can be significant, particularly for narrow therapeutic index medications.
UK vs US Teaspoon: How Big is the Difference?
The US teaspoon is defined as 4.928922 ml (often rounded to 4.929 ml). The difference from the UK 5 ml teaspoon is approximately 0.071 ml per teaspoon — a tiny but measurable amount.
For everyday cooking this difference is completely negligible. A US recipe calling for 2 teaspoons of vanilla extract would give you 9.858 ml; the UK interpretation gives 10 ml. In a cake recipe, this makes absolutely no perceptible difference.
However, this difference becomes more significant when scaling up. A recipe using 20 teaspoons of a particular ingredient would deliver 98.58 ml by US measure versus 100 ml by UK measure — a 1.4 ml difference that is still unlikely to matter in cooking but illustrates how small errors compound.
The Australian Tablespoon Trap
While the UK and US teaspoons are very close, the Australian tablespoon causes genuine recipe confusion. An Australian tablespoon is 20 ml — not 15 ml like the UK — making it equivalent to 4 Australian teaspoons (each still 5 ml). This means an Australian recipe calling for "2 tablespoons" of butter would require 40 ml, while a UK cook using the same instruction would only use 30 ml. That is a 33% difference, enough to significantly alter many recipes.
If you are adapting Australian recipes (from Australian cookbooks, food blogs, or cooking shows), always check whether tablespoon measures might be the 20 ml Australian standard. Cakes, sauces, and baked goods are particularly sensitive to this discrepancy.
Cooking Accuracy: Why Weighing Beats Volume
Professional bakers and serious home cooks in the UK increasingly measure ingredients by weight rather than volume, even for small quantities. The reason is simple: density varies. One teaspoon of sifted icing sugar is much lighter than one teaspoon of compacted brown sugar. One teaspoon of table salt weighs more than one teaspoon of flaky sea salt.
Despite this, teaspoon and tablespoon measures remain essential in cooking for several reasons:
- Spices and dried herbs: The differences in density matter less at small quantities, and weighing 0.5 g of paprika is impractical on most kitchen scales.
- Liquids: For liquids like vanilla extract, lemon juice, or olive oil, 1 teaspoon = 5 ml is accurate enough for all culinary purposes.
- Baking powder and bicarbonate of soda: These leavening agents are typically used in teaspoon quantities, and the standardised 5 ml measure gives consistent results.
- Recipe accessibility: Not everyone has precision kitchen scales, and teaspoon measures are accessible to all home cooks.
Medicine Dosing: Why the NHS No Longer Uses "Teaspoons"
The NHS has progressively moved away from teaspoon-based dosing in favour of ml measurements. Current NHS guidance for children's medicines specifies doses in millilitres exclusively, even though a 5 ml dose is, by definition, one teaspoon. This change was driven by medication error research that showed:
- Parents measuring with kitchen spoons frequently gave the wrong dose by 20–50%.
- Confusion between teaspoon and tablespoon measures led to some children receiving three times the intended dose.
- Oral syringes dramatically reduce dosing errors for liquid medicines.
Common UK Recipe Conversions
Understanding teaspoon and tablespoon ml equivalents helps you adapt recipes, scale quantities, and measure consistently. Here are the most useful conversions for UK kitchens:
- ¼ tsp = 1.25 ml (used for tiny quantities of spices)
- ½ tsp = 2.5 ml (half a teaspoon)
- 1 tsp = 5 ml
- 1½ tsp = 7.5 ml
- 2 tsp = 10 ml
- 1 tbsp = 15 ml = 3 tsp
- 2 tbsp = 30 ml = 6 tsp
- 4 tbsp = 60 ml = ¼ cup (UK)
- 100 ml = 20 tsp = 6.67 tbsp
Frequently Asked Questions
In the UK, 1 teaspoon = 5 ml exactly. The US teaspoon is 4.929 ml. For all UK cooking and medicine, use 5 ml as your standard teaspoon measure.
Yes. In the UK, 5 ml is exactly one teaspoon. This is standardised for cooking, baking, and medicine. Pharmacy measuring spoons and NHS oral syringes are calibrated to this standard.
A UK tablespoon is 15 ml (3 teaspoons). A US tablespoon is 14.787 ml. An Australian tablespoon is 20 ml — watch out when using Australian recipes.
No, but the difference is tiny. UK = 5 ml, US = 4.929 ml. The 0.07 ml gap is irrelevant for cooking. For medicine, always use the UK 5 ml standard when following NHS or UK pharmacy guidance.
There are 3 teaspoons in 1 tablespoon in the UK and US (UK: 3 × 5 ml = 15 ml). In Australia, 1 tablespoon = 4 teaspoons (4 × 5 ml = 20 ml).
The correct UK medicine teaspoon is 5 ml, standardised by the British Pharmacopoeia and NHS. Never use a kitchen teaspoon for medicine — they vary from 3–7 ml. Use a proper oral syringe or medicine spoon.