Sometimes it's hard to tell if the bowl-shaped feature at the top of a volcano is a crater or a caldera. you can usually determine if it's one or the other by

By finding if the volcano type is active or extinct.

Explanation:

A vent for the molten rock to move out on to the surface of the Earth is known as a crater. On the other hand, the outcome of a huge volcanic eruption that emits a large volume of magma leaving behind a large opening in the ground is known as a caldera.  

The formation of calderas takes place when the large chamber of magma gets vacant by the subsurface movement of the magma or by a volcanic eruption. The rock, which forms the roof of the magma chamber that has no support then get collapsed to produce a big crater.  

Size of the depression and the deposition of materials outside the volcano or subsidence of the materials inside the volcano.

Explanation:

A crater is usually defined as a bowl-shaped depression that is often created due to any meteoric impact, volcanic eruptions or due to any large explosion. The craters that are originated from volcanic eruptions are normally deep and have steep sides but also sometimes they are wide and very shallow in nature.

Craters and calderas looks the same but they are actually different. Craters are created when the rocks and other pyroclastic type of materials are ejected from a volcano, whereas Calderas are created by the inward subsidence of a volcano’s magma chambers. The size of the Craters are usually very much smaller in comparison to the calderas.

So, it can be concluded that if the size of these depressions are small then those are craters and if they are extensively large then they are calderas. Moreover, if the materials from the volcanoes are deposited outside then it indicates a crater and if these materials are found to be accumulated inside the volcano then it indicates a caldera.