Based on the sales of the latest entries, I would say Tomb Raider is bigger.

Agree

Edit: But I don't think Bloodborne or Tomb Raider can sell more than Zelda given their sales story

Edit 2: Dark Souls sold 2.4m across 3 platforms (according to Vgchartz) while the latests console Zelda sold 3.8m in a dying console

Edit 3: According to VgChartz TR sold 4.5m (not including the definitive version) and while that's more than the latest console Zelda, it was across 3 platforms and not just 1 like Zelda, so if we consider that Rise of the Tomb Raider is Xbox One exclusive then, I can see it not selling even the half of what the first game did.

I have a feeling that Zelda U will score the highest, rise of the tomb raider will sell the most, and Bloodborne will cause the strongest sales for hardware. Maybe Blood will sell more too. I dunno. I don`t have a crystal ball or anything to tell you ; )

Install base doesn't do much good if you fund the marketing campaign for your game with the change you find under your couch cushions.  You can't just look at one or two sets of numbers, you have to look at *all* the variables.

You mean the game that sold 4.5m across 3 platforms? We don't even have actual numbers for Skyward Sword; it's likely that it sold around 5m by now (considering the number we have, 3.88m, is from the year it launched) on one platform. 

I mean, you can't be talking about any other Tomb Raider game, because all of the other 'recent' entries sold around 2m or less. Yeah, definitely bigger than Zelda.

No, the game that sold 7.5M.

So you're counting the Definitive Edition. That's fair. 

Even then, the sales of the two games are comparable and we're talking about the entire franchise, not two games. Zelda as a whole has been wildly more successful than Tomb Raider could ever dream to be. TR's peak is nowhere near Zelda's peak, TR's LT sales aren't even close to Zelda's LT sales, and at this point, Tomb Raider has to be multiplatform to be successful in Square Enix's eyes. One game does not change a franchise's history.

Yeah but even if we remove the Definitive Edition, I'm pretty sure it outsold Skyward Sword.

By how much though? Let's say the Definitive Editions sold 2m combined (which isn't an unfair assumption). That would put the regular version at 5.5m. Like I said earlier, I think SS is easily above 5m at this point. But let's just say it stopped right at 5m (which would be insane to think that it only sold 1.2m for the remainder of its life). That means TR only outsold it by 500k, even with being on 2 more platforms than SS, and taking into consideration that SS needed a Wiimote Plus to even play it. Is an additional 500k worth of sales really subsantial enough to wipe away years and years of history, where Zelda sold consistently high while Tomb Raider was on its death bed? I think not.

Saying a gamer is bigger than another game is entirely different than saying one franchise is bigger than another franchise. 

I have to say Zelda, why? ok I'm a fangirl, but I love the "souls" games too. But my real opinion, Bloodborne looks amazing and the game looks like a perfect progression for the genre, but I think that zelda wii u is going to be one of those "game changers" games. Plus the franchise is a lot bigger, but that's another theme. Tomb Raider, I don't know what to expect.