Does a spell with kicker count as a higher mana value on the stack?

A spell's mana value (formerly called converted mana cost) is always determined by its printed mana cost, regardless of any additional costs paid to cast it. This is established in CR 202.3, which states that the mana value of an object on the stack is calculated from its mana cost — and kicker is an additional cost, not part of the mana cost.

Kicker is defined under CR 702.33 as an optional additional cost. Even if you pay the kicker, that extra mana does not factor into the spell's mana value. The mana value stays the same whether you kick the spell or not.

This matters for effects that care about mana value — for example, if you cast a kicked Burst Lightning (which has a mana cost of {R}), its mana value is still 1 on the stack, even though you paid {5} total. An opponent's Spell Snare (which counters a spell with mana value 2) could not counter it.

The only exception involves spells with X in their mana cost. For those, X is the value chosen as you cast the spell, and it IS included in the mana value while the spell is on the stack (CR 202.3b). But kicker has no such rule and is never folded into the mana value calculation.