Ceramic or Porcelain? A common dilemma when it comes to choosing tiles is whether to pick ceramic or porcelain. What is the difference? Which do I need? Is one better than the other? Let's just take any doubt away and compare these two materials.

Porcelain and ceramic tile are essentially the same, with one slight difference.

Ceramic tiles are made from natural clay with a durable glaze; the biscuit of the tile is baked to reduce water content. Next the design is added to the same biscuit before it’s baked again in a kiln at a high temperature.

Porcelain tiles are also made from natural clay but of a denser nature, finely ground sand is also added into the manufacturing mix. This mixture is then pressed and fired at a much higher temperature than ceramic tiles, and also for longer to remove almost all of the water content.
Porcelain tile has a water absorption rate of 0.5% as defined by American Society for Testing and Materials (ASTM) C373. Fired tile is weighed. Then it is boiled for 5 hours and then let to sit in water for 24 hours afterward. Then it is weighed again. If the tile weighs less than half of one-percent more as a result of water absorbing into its surface, it is considered porcelain.
Porcelain tile is often extruded; has less impurities than ceramic; is often rectified; and often contains more kaolin than ceramic. It's formed of quartz, clay, and feldspar that is fired at temperatures ranging from 1200-1400 degrees C.
But since that also defines many ceramics, again the difference is that porcelain has that 0.5% or less water absorption rate.
The Porcelain Enamel Institute rating (PEI rating) is a great tool to help you determine the recommended application for a tile. All tiles are classified with a PEI rating and the scale is as follows:

PEI 0 – No foot traffic (wall tile only)
PEI 1 – Very light traffic (e.g. bathroom)
PEI 2 – Light traffic (e.g. bathroom and bedroom)
PEI 3 – Light to moderate traffic (e.g. most domestic floors)
PEI 4 – Moderate to heavy traffic (e.g. entrance, hallway, kitchen, balcony and some commercial applications)
PEI 5 – Heavy traffic (all domestic/commercial uses with heavy abrasion/footfall)
Most ceramic floor tiles will carry a PEI rating from 3 to 4 with porcelain tiles ranging from PEI 3 to 5. Still unsure which tile you should be using where? Make full use of our expertise and get in touch with a member of our customer service team who’ll be able to help you.

Laying porcelain or ceramic tile outside is typically not recommended. Ceramic is usually not durable enough for exterior use because it absorbs too much water. If you live in areas which freeze, your tile would likely crack on the first freezing night. Stone is a better option.