Zolom recommended level to kill.

[Darkdan777]

As the title says.

[Koolkit]

You can kill him right after you get out of Kalm, though it will take quite a while. Just put all your party members in the back row with tranquilizer and cast bio on him until he gets poisoned. Then just wait it out.

[NinjutStu]

It depends, but you aren't supposed to be able to kill him prior to around the time you get the buggy. That being said, there are strategies that let you kill him as early as Kalm.

Specifically, what you need to kill him is the flame ring (or fire ring, can't remember offhand what's it called) that makes you immune to fire. Zolom's beta enemy skill will do 1200 or so damage, but no damage to whoever has the accessory on. You just need to keep the HP high of whoever has the ring on and then have them spam their best limit break / Shiva and you're good.

Or you could just come back much later and decimate him. He doesn't go anywhere.

[Darkdan777]

I beat him at lvl 19 kept knocking cloud out tife dies and barret kicks ass

[markdb92]

you can kill the 2 people who dont have emeny skill materia equiped before you battle so you dont get knocked out.

[Commisar Jon Fuklaw]

Zolom is easy to kill right out of Kalm if you spent a bit of time grinding gil near the chocobo farm. Choco summon and bio are your friends, as are limit breaks.

[Zork Nemesis]

Like the others say, you can beat him out of Kalm, but it's very dangerous. What you'll want to watch out for is Beta (which I assume is why you fight it anyway at this point) which is capable of doing 1300+ damage to your entire party, likely leading to an instant wipe.

If you're set on beating him so early, you'll want the Elemental materia you can pick up in the Shinra HQ for guessing the mayor's password on the first try. Link it with a Fire materia and put it in your armor. This should cut Beta's damage down to half but it will still do a lot of damage at the level you'll be fighting it at and the Zolom tends to follow up on Beta with an attack (if he's not dead).

What you really should do is wait until after Corel to go fight it. At that point you'll have two of the Enemy Skill materia, the buggy, and the Flame Ring in Costa del Sol which nullifies fire damage. This way you can save a trip and you can come back for the Mithril for Great Gospel at the same time if you're going for it. There's no other reason to fight the Zolom besides for Beta; his exp and ap rewards are kinda crappy. I say it's worth putting off for a bit, especially if you picked up Matra Magic near Midgar anyway. Matra Magic will carry you through Corel.