Is 5 mL the same as 1 teaspoon?

Quick Answer

No, 5 mL is not exactly the same as 1 teaspoon. However, they are close approximations. 1 teaspoon is approximately 5 mL, but not exactly. There is a slight difference between the two measurements.

Measuring Volume vs Weight

Part of the confusion around whether 5 mL equals 1 teaspoon comes from the fact that teaspoons are a unit of volume, while mL are a unit of volume.

Volume measures the amount of space something takes up. For example, 5 mL takes up a certain amount of space.

Weight measures how heavy something is. For example, 5 g indicates a certain weight, not volume.

So when comparing teaspoons and mL, we are comparing two units of volume, not weight.

Metric System vs Imperial System

Another source of the confusion is that mL and teaspoons come from different measurement systems.

mL stands for milliliters and is part of the metric system. The metric system is based on the number 10. All volumes in the metric system are measured in units based on multiplying or dividing 10.

Teaspoons are part of the imperial system commonly used in the United States. The imperial system is based on non-decimal numbers like 12 inches in a foot. Teaspoon sizes can vary slightly based on how the utensil was made.

Since the two measurement systems are different, there is no perfectly neat conversion between teaspoons and mL. However, approximate conversions are widely used.

Approximate Conversions

Since teaspoons and mL are different units from different measurement systems, conversions between them are based on approximations:

– 1 teaspoon is approximately 5 mL
– 1 tablespoon is approximately 15 mL
– 1 fluid ounce is approximately 30 mL
– 1 cup is approximately 240 mL

However, it’s important to remember these are approximations. Converting between systems will introduce a small margin of error.

The approximation commonly used is:

– 1 teaspoon = 5 mL

So while they are not exactly equal, they are sometimes used interchangeably in recipes and instructions for convenience. However, for scientific applications requiring high precision, the slight difference between 1 teaspoon and 5 mL must be taken into account.

Why Are They Approximately Equal?

The reason why 1 teaspoon and 5 mL are approximately equal comes down to the definition of these units.

A teaspoon was originally defined as the amount of liquid that fit into an actual spoon of that size.

A milliliter was defined based on the metric system as 1/1000 of a liter.

It turned out that the amount of liquid that fit into a common teaspoon was very close to 5/1000 of a liter, or 5 mL.

But since these units were defined independently, they ended up with slightly different volumes.

This small difference doesn’t matter for cooking and everyday measurements. But for scientific applications, the difference becomes significant.

The Actual Difference

So exactly how much of a difference is there between 1 teaspoon and 5 mL?

There are a few factors that make teaspoons variable:

– Teaspoons can be produced in different sizes by various utensil makers.
– How full the teaspoon is can vary based on how someone fills it. A “rounded” teaspoon that is heaped a bit will hold more than a flat, leveled teaspoon.
– Factors like temperature, altitude, and the density of the liquid also impact volume measurements slightly.

But most sources agree that the difference between 1 teaspoon and 5 mL is around 0.9-1.2 mL.

So a single teaspoon holds about 5.9-6.2 mL rather than a precise 5 mL. Over multiple teaspoons or tablespoons, this discrepancy compounds.

When Precision Matters

For most household uses, the approximation of 1 teaspoon = 5 mL is good enough. When making dinner or following a recipe, that level of accuracy is perfectly acceptable.

However, for scientific, medical, and technical applications, the slight difference between teaspoons and mL matters.

Here are some examples where precision is important:

– Medical dosing: Medicines are measured carefully for safety. Even small dosage differences impact the potency.

– Chemical experiments: Using the precisely correct amount of each chemical is key to successful experiments.

– Cooking delicacies: For advanced culinary techniques, the exact volume of ingredients is often critical.

– DIY projects: Measuring out the ideal amounts of paints, finishes, epoxies, etc. for DIY projects leads to better results.

So while teaspoons can substitute for mL in everyday situations, for precision applications it’s better to actually measure in mL to avoid even small margins of error.

Converting Between Teaspoons and mL

Since teaspoons and mL are not exactly interchangeable, you need to convert between them carefully when precision matters.

Here are the best ways to convert:

– Use conversion charts that show exact teaspoon and mL amounts. Don’t rely only on the 1 tsp = 5 mL approximation.
– For critical applications, actually measure in mL with an instrument designed for metric measurement for accuracy.
– Or measure first in teaspoons, then use a conversion calculator to find the precise mL amount. An online converter can handle the math for you.
– For recipes, stick consistently with one unit or the other. Don’t mix teaspoons and mL in the same recipe.

Converting diligently between units prevents over-reliance on the spoonful/mL approximation.


In summary, 5 mL is not exactly equal to 1 teaspoon. The approximation commonly used is 1 tsp = 5 mL, but due to differences between measurement systems, there is a slight variance:

– Teaspoons (imperial system) and mL (metric system) are different units
– 1 teaspoon is approximately 5 mL, but not precisely equal
– The actual difference is around 0.9-1.2 mL per teaspoon
– For everyday uses, this small difference doesn’t matter
– For scientific applications requiring precision, the difference becomes significant
– To convert precisely, use conversion charts or actually measure in mL, don’t rely only on the approximation

So while they are often substituted for each other as convenient abbreviations, to ensure accuracy it is important to understand 5 mL and 1 teaspoon are not exactly the same. The context of the situation dictates whether the approximation is sufficient or an exact conversion is required.

Frequently Asked Questions

Why do recipes use both mL and teaspoons if they are not exactly equal?

Recipes often use teaspoons and mL interchangeably because for cooking the approximation is close enough. The small margin of error won’t significantly impact the dish. Using both units also allows cooks familiar with one system or the other to follow along. However, for baking that requires more precision, recipes should stick with one unit to avoid compounding errors.

Can I measure 5 mL and 1 teaspoon and see if the volumes look the same?

If you measure out 5 mL of water and 1 teaspoon of water side by side, they will look very similar, but not necessarily identical. The small 0.9-1.2 mL difference is difficult to see with the naked eye. You would need very precise laboratory glassware to actually observe the volume difference visually. For a tangible demonstration, measure out larger volumes – the difference between 50 mL and 10 teaspoons (about 60 mL) is more readily apparent.

Does the type of liquid make a difference in the teaspoon/mL approximation?

Yes, the density and viscosity of the liquid does impact the volume relationship slightly. For example, 1 teaspoon of water will not be exactly the same volume as 1 teaspoon of oil. However, for most household uses the density differences between liquids are not significant enough to worry about. But at precise laboratory levels, the type of liquid being measured would need to be considered.

Can I just increase a recipe’s amounts by 20% if it uses teaspoons instead of mL to make it more precise?

No, simply increasing all the teaspoon measurements evenly by 20% won’t make the recipe more precise. The ratio of ingredients to each other is what matters, not just the total amounts. Also, a 20% change is far more than the actual 1 teaspoon to 5 mL difference. You would have to convert each original teaspoon amount to mL individually using a reliable conversion formula for true precision.

The Bottom Line

While teaspoon and mL conversions are based on approximations for convenience in everyday situations, they should not be considered exactly equal when precision matters. To ensure accuracy in applications like cooking, science, and medicine, conversions between units should be handled carefully and precisely.

Unit Volume
1 teaspoon 5-6 mL
1 tablespoon 15 mL
1 fluid ounce 30 mL
1 cup 240 mL

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