Transparency time!

So, the tooltips right now will be a little misleading. Base Level is item level, sort of. There's a number of things that factor into the overall power of a item. Unfortunately, Required Level currently takes the place of Base Level on the tooltip. Which means that you can't really tell the actual item level of an item with a required level without doing some reverse engineering on the stat allocation; and even then there is more to it, such as ...

Item Offset - player-facing con color; adds addition levels to an item's power. For example, a Blue item is 2 levels higher than a Green item; Purple is 2 levels higher than a Blue and so on.

Multi-Stat Multiplier - In short, the more stat sockets an item has, the more its base power is multiplied. A 4 stat item has slightly more budget than a 3 stat item; because the budget is divided more equally across 4 stats than 3 stats. But, in general, you'll always want an item with more stat sockets.

We also have a system called Elder Tiers, which comes into play at level 50. None of our items are actually over base level 50, but we still need to give them more power as content tiers progress. This is an Elder Tier. Each Elder Tier also adds another 2 levels to the item. Currently, this is not directly communicated to the player. We are in the process of updating all the level 50 items to the correct Elder Tier. The level 50 items you are playing with now are actually fairly underpowered (by beween 2 and 6 item levels).

And then Runes can also affect the overall items total power. Most dropped items can have a random number of rune slots (although we're tightening this up a bit) and rune slots can be random colors.