How Many mL in a Teaspoon? US, Metric & UK Volumes Explained

If you’ve ever stared at a recipe that calls for a teaspoon of an ingredient and wondered exactly how much that is in milliliters, you’re not alone. The answer gets a little complicated depending on where you live and what you’re measuring. Whether you’re cooking, baking, or giving medicine, knowing the precise milliliter equivalent can make a real difference.

Standard US teaspoon: 4.928922 mL · Metric teaspoon: 5 mL · UK teaspoon: 5.91939 mL · Medicine dosing teaspoon: 5 mL

Here is a quick comparison of the three major teaspoon standards and their equivalents.

For an expanded breakdown, here are all key teaspoon-to-milliliter conversions at a glance.

Is 5 mL the same as 1 teaspoon?

Standard US vs metric teaspoon volume

• The US customary teaspoon equals exactly 4.92892159375 mL, according to the NIST (U.S. measurement authority).
• Many metric countries define 1 teaspoon as 5 mL, as confirmed by SafeMedication.com (medication safety resource).

Why medication dosing uses 5 mL

For practical medicine dosing, 1 teaspoon is universally rounded to 5 mL. SafeMedication.com (medication safety resource) states that liquid medication guidance treats 1/2 teaspoon as 2.5 mL and 1 teaspoon as 5 mL. The implication: the tiny 0.07 mL difference between 4.93 and 5 mL is considered acceptable for most recipes, but for medications, the standardized 5 mL rule is what you should follow.

The pattern: the closer you get to precision-critical applications, the more the US versus metric gap matters.

Is a teaspoon 15 or 20 mL?

Common teaspoon misconceptions

No. A teaspoon is never 15 or 20 mL. That confusion usually comes from mixing up “tsp” (teaspoon) and “tbsp” (tablespoon). A tablespoon is roughly three times larger.

Difference between teaspoon and tablespoon

• 1 US tablespoon = 14.7868 mL (NIST (U.S. measurement authority)).
• 1 metric tablespoon = 15 mL.
• 1 teaspoon = 1/3 of a tablespoon (roughly 4.93–5 mL).

The trade-off: getting the wrong spoon can throw off a recipe or, far more critically, a medication dose. Double-check the label.

Is 2 teaspoons the same as 10 mL?

Exact conversion for US teaspoons

2 US teaspoons = 2 × 4.928922 mL = 9.857844 mL. That’s slightly less than 10 mL.

Metric conversion for 2 teaspoons

2 metric teaspoons = 2 × 5 mL = 10 mL exactly. Omni Calculator (conversion tool) confirms that in metric contexts the rounding is standard. For most cooking, rounding 9.86 mL to 10 mL is perfectly fine. For precise baking or pharmaceutical compounding, the 0.14 mL difference might matter. The pattern: the closer you get to exact science, the more the US vs metric gap shows.

How many ml in a teaspoon in different countries?

US teaspoon volume

4.928922 mL (exact).

UK teaspoon volume

5.91939 mL historically, but modern UK recipe guidance often treats it as 5 mL, per The Chef Royale (cooking reference).

Metric teaspoon (Australia, NZ, Canada)

5 mL. Mediterranean Taste (food blog) states “there are 5 ml in a teaspoon” as a general rule, noting real-world variation.

Japanese teaspoon

Japan uses the metric system, so 1 teaspoon = 5 mL.

Comparing teaspoon volumes across countries reveals the variations.

NIST (U.S. measurement authority) notes that the difference between 4.93 mL and 5 mL is small but nonzero. The implication: if you’re following a recipe from another country, check whether it uses US customary or metric teaspoons.

How many mL is a teaspoon of medicine?

Safety of using kitchen teaspoons for medicine

Never use a kitchen spoon to measure liquid medicine. SafeMedication.com (medication safety resource) warns that household cutlery teaspoons are not standardized and should not be assumed to equal a medicine dosing teaspoon. A U.S. Pharmacist (pharmacy journal) article reports that labeling doses in milliliters can decrease dosage errors by 50%.

Proper dosing tools

Always use the dosing device that comes with the medicine (syringe, dropper, cup). If it’s missing, ask a pharmacist. Advocare North Jersey Pediatrics (pediatric practice) publishes a chart showing 1 teaspoon = 5 mL = 5 cc = 1/3 tablespoon.

The trade-off: convenience vs. safety. A kitchen spoon is quick, but the cost of a dosing error outweighs the few seconds it takes to find the proper tool.

The size of teaspoons ranges from about 2.5 to 7.3 mL.

— Wikipedia (encyclopedic reference)

There are 5 ml in a teaspoon. Note, although a standard measuring teaspoon generally falls around 5 milliliters, there can be differences between teaspoons.

— Mediterranean Taste (food blog)

For home cooks and parents giving liquid medicine, the choice between 4.93 mL and 5 mL may seem trivial, but in precision-critical scenarios like medication dosing, the difference can be significant. The safest route: use milliliters, not spoon sizes. For the kitchen, a decent measuring spoon set removes the guesswork. For the medicine cabinet, the only rule is to follow the device that came with the bottle. For anyone in the U.S. who regularly handles both recipes and medications, the practical takeaway is to own a set of standard measuring spoons for cooking and to demand milliliter markings on all liquid medicine labels.

Understanding the exact volume of a teaspoon can be tricky, but a comprehensive guide to US, UK, and metric teaspoon conversions clarifies the variations across measurement systems.

Frequently asked questions

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