Last Updated on September 12, 2025
Increase Inventory Space BL4: I’ve been grinding the game for almost 5-6 hours. The game runs pretty smoothly at 1440p, but one thing that’s been bothering almost everyone is the inventory space. You start with just 16 slots, which is absolutely terrible when you’re trying to loot everything in sight.
The loot system in Borderlands has always been about collecting tons of weapons and gear, that’s the whole point. But with such limited space at the start, you’re constantly running into “inventory full” messages. Due to which they are not able to enjoy the looting experience properly. I’ve seen people complaining about this on Reddit already, and honestly, it’s a valid complaint.
Read: How To Fix Lag & Stuttering in Borderlands 4
The SDU System – Your Permanent Solution
Storage Deck Upgrades, or SDU for short, is what you need for permanent backpack expansion. These work similar to the previous Borderlands games but the costs have changed quite a bit. The first backpack upgrade costs only 5 SDU which is pretty reasonable, but it gets expensive real quick.
Here’s the complete breakdown for backpack upgrades:
| Level | SDU Cost | Slots Added | Total Slots |
|---|---|---|---|
| 0 | – | – | 20 |
| 1 | 5 | +4 | 24 |
| 2 | 10 | +4 | 28 |
| 3 | 20 | +6 | 34 |
| 4 | 30 | +6 | 40 |
| 5 | 50 | +6 | 46 |
| 6 | 80 | +8 | 54 |
| 7 | 120 | +8 | 62 |
| 8 | 235 | +12 | 74 |
The exponential cost increase is pretty brutal. Getting to level 8 requires 550 SDU total, which takes quite a bit of farming. But honestly, even getting to level 3 or 4 makes a huge difference in gameplay experience.
You can earn SDU from various activities throughout the game. Safehouses give you around 40 SDU each, which is really good. Order Silos also provide similar rewards. The collectibles like Survivalist Caches and Evocariums give you 5 SDU each, so they add up if you’re exploring properly.
Bank Storage – Quick Fix That Actually Works
While you’re farming SDU for permanent upgrades, there’s a temporary solution that many players don’t know about. Press Tab to open your inventory, you’ll see a Bank icon on the top right corner of the screen. This is separate storage space that you can use to dump items you don’t need immediately.
Right-click any item to mark it for transfer, then hold V to move everything to your bank. This frees up your backpack space instantly. The bank also has limited space initially, but you can upgrade it with SDU just like your backpack. I usually dump all the lower-tier weapons there and sell them in bulk later.
Someone in the Steam forums mentioned that they use the bank to store weapons for their other characters too, which is pretty smart. You can also store gear with Firmware mods there since those are usually worth keeping.
Which Upgrades Should You Prioritize
Storage-wise, backpack should definitely be your top priority. After that, I’d recommend bank upgrades, then Lost Loot machine capacity.
The Lost Loot machine stores items you missed or couldn’t pick up during fights. This is actually really useful since legendary drops can get lost in the chaos of combat. I am not sure why they made the default capacity so low, that too when there’s so much loot dropping constantly.
Weapon ammo upgrades are less important early on. There are plenty of ammo boxes and vending machines around the map, so you won’t run out of ammo often. Focus on storage first, then worry about ammo capacity later.
The game costs $69.99 currently, which is pretty standard for AAA releases. But the inventory management issues make it feel like the game needed a bit more polishing before release. Hopefully they’ll increase the starting capacity in future updates, probably furnished with other quality of life improvements.
You can find more gaming guides and tips on our website. Comment below if this helped you sort out your inventory problems.