Don’t Blow Your Eridium: Best Uses and Fast Ways to Farm It in Borderlands 4
Eridium in Borderlands 4 is a rare resource used for a few specific services — and because it’s limited, you’ll want to spend it carefully. Below is a clear, factual guide to what you can buy with Eridium and the reliable ways to earn more while you play.
How to use Eridium in Borderlands 4
There are three concrete uses for Eridium right now. Each one is tied to a machine or menu, and each costs a fixed amount when you use it.
Weekly Moxxi’s Big Encore
If a boss has a Big Encore machine outside its arena, you can redo that fight. Normally this costs cash, but for the weekly buffed version of the boss you must pay 100 Eridium instead of cash. This weekly option appears as part of the weekly challenges and is a good way to farm stronger loot, especially legendaries. Also, you can identify the weekly boss by the red boss icon on the map or by checking the map menu in the lower-left.
Respeccing Specialization points
Specialization unlocks only after you finish the campaign once. It gives extra skill trees and passives for endgame builds. To refund your Specialization points you must use the respec machine and pay 5,000 Eridium per respec. Therefore, respeccing is available but very expensive, so plan builds carefully before committing.
Firmware transfer
Firmwares are bonus effects that can spawn on repkits, ordnance, class mods, shields, and enhancements. You can move a firmware from one item to another at a transfer machine. The cash cost varies with the items, but the machine consistently charges 80 Eridium for the firmware transfer action itself.
How to get Eridium in Borderlands 4
Eridium isn’t abundant, and there’s no known infinite farm. Still, several repeatable activities reliably award small amounts, so you can build up a reserve over time.
Missions, contracts and challenges
Playing the game is the simplest route. You can earn Eridium from campaign quests, side missions, challenges, and especially from contracts (bounties and patrols). Contracts are usually the fastest repeatable option because bounty targets are easy to find and repeat.
Safehouses, Silos and command consoles
Exploring helps too. Unlocking Safehouses and Silos and claiming their command consoles rewards 25 Eridium per location, but note that the console reward is granted once per location. Use an interactive map to prioritize fresh locations you haven’t claimed yet.
World bosses and random drops
World bosses can drop Eridium as well. For example, at level 38 testing, defeating bosses like Saddleback and the Immortal Boneface awarded 25 Eridium. Regular enemies and random loot can also drop Eridium, but those sources are less reliable than quests and locations.
In short: spend Eridium on the three specific services when it matters, and earn more by doing contracts, clearing unclaimed Safehouses/Silos, and tackling world bosses. Above all, be selective — respeccing and some transfers are expensive, so save Eridium for the moments that will give the best return.
