Only person not experiencing lag?

Hello! I run a server, TobyCraft, and it seems a lot of my users have been complaining recently about there being lag. I am not experiencing this and therefore cannot recreate the issue. It is NOT because I am on the same network/computer because my server is located in California, all the way across the country from where I am. I have listed the server specs and the plugins below:

RAM: 4GB HDD
Worlds: 13
Plugins: Orebfuscator, PlugMan, JustWarp, NoCheatPlus, InvisibleBlock, WorldEdit, KittySmite, CommandBook, WirelessRedstone, Vault, BanHammer, PermissionsEx, Multiverse-Core, LogBlock, MyCommand, NoSnow, WorldGuard, Jail, InfinitePlots, MineBackup, AutoMessage, SimplyVanish, RAM, iConomy, SurvivalGames, ReportRTS, CommandHelper, Tropic, PacketManager, ChestShop, Modifyworld, InfiniteClaims, MobArena, iChat, MobDisguise, CleanroomGenerator, Factions, Citizens, Multiverse-Portals, SetRankPEX

I believe it is a plugin, but... I have no clue.

Thank you!

-TobyG123

 

If you are hosting the server on youre computer, Ofc you wont have any lagg. You need to take into point youre internet. upload speed and download speed.