Blast Furnace Cost in OSRS: A Detailed Guide to Expenses and Profits
The Blast Furnace in Old School RuneScape (OSRS) is a popular minigame for players looking to level up their Smithing skill or make some serious in-game gold (GP). Located in Keldagrim, this members-only activity offers efficient smelting with half the coal requirement of a standard furnace, making it a go-to for both XP grinders and money-makers. However, the costs associated with using the Blast Furnace can add up quickly if you’re not prepared. In this guide, we’ll break down the Blast Furnace cost in OSRS, including fees, gear, supplies, and potential profits, so you can maximize your time and GP.
Before diving into the costs, let’s cover what the Blast Furnace is and why it’s worth your attention. This minigame allows players to smelt bars in bulk, using only half the coal typically needed for ores like steel, mithril, adamantite, and runite. On designated Blast Furnace worlds (e.g., Worlds 352, 355, 358, 386, 387), five dwarves—Dumpy, Stumpy, Pumpy, Numpty, and Thumpy—handle the mechanics, letting you focus solely on loading ores and collecting bars.
How to Access the Blast Furnace
To use the Blast Furnace, you need to start The Giant Dwarf quest to unlock Keldagrim. You can reach it via the minecart from the Grand Exchange, a minigame teleport, or by walking from Seers’ Village. Once there, head to the eastern side of the city and descend into the furnace building.
Why Use the Blast Furnace?
- Coal Efficiency: Only half the coal is needed per bar, reducing resource costs.
- Bulk Smelting: Smelt entire inventories at once, boosting XP rates.
- Profit Potential: High-tier bars like mithril, adamant, and rune can yield significant GP.
Breaking Down the Blast Furnace Costs in OSRS
The Blast Furnace isn’t free to use, and the costs vary depending on your Smithing level, the worlds you choose, and the supplies you bring. Let’s dissect the expenses you’ll encounter.
Hourly Fee on Blast Furnace Worlds
On the 15 designated Blast Furnace worlds, you’ll pay 72,000 GP per hour (or 12 GP per game tick) to keep the dwarves operating the furnace. This fee is deposited into the coffer near the bank chest and is deducted only while you’re logged in. If you hop worlds or log out, the timer pauses, preserving your remaining funds.
Smithing Level Fee (Below 60)
If your Smithing level is below 60, you’ll face an additional cost: 2,500 GP every 10 minutes to use the furnace. This equates to 15,000 GP per hour on top of the 72,000 GP fee, totaling 87,000 GP per hour. However, wearing a Ring of Charos (a) and following the right dialogue (Chat 1-3-2-3) with the Foreman cuts this to 1,250 GP per 10 minutes, or 7,500 GP per hour, reducing your total to 79,500 GP per hour.
Ore and Coal Costs
The biggest variable expense is the raw materials—ores and coal. Prices fluctuate based on the Grand Exchange (GE), but here’s a snapshot as of April 08, 2025:
| Material | GE Price (GP) | Notes |
|---|---|---|
| Iron Ore | 60-80 | No coal needed for iron bars |
| Coal | 130-150 | Half required at Blast Furnace |
| Mithril Ore | 150-170 | Needs 2 coal per bar |
| Adamantite Ore | 1,000-1,200 | Needs 3 coal per bar |
| Runite Ore | 11,000-11,500 | Needs 4 coal per bar |
| Gold Ore | 350-400 | No coal; used for XP with Goldsmith Gauntlets |
You can buy these from Ordan’s Ore Seller in Keldagrim, but GE prices are often cheaper. A coal bag (unlocked via Dungeoneering) doubles your coal capacity per trip, cutting banking time and costs.
Stamina Potions and Gear
Running between the bank, conveyor belt, and bar dispenser drains your energy fast. Stamina potions (around 6,000-7,000 GP for a 4-dose vial) are essential for efficiency, with 36 doses per hour costing roughly 54,000-63,000 GP. Weight-reducing gear like the Graceful outfit or Boots of Lightness helps, but these are one-time investments (Graceful costs ~2M GP total).
Calculating Total Costs Per Hour
Let’s estimate your hourly expenses based on different scenarios:
Iron Bars (Low-Level, Profit-Focused)
- Fee: 79,500 GP (below 60 Smithing with Ring of Charos)
- Iron Ore: 5,800 bars x 70 GP = 406,000 GP
- Stamina: 60,000 GP
- Total Cost: ~545,500 GP
Selling 5,800 iron bars at 100 GP each = 580,000 GP, netting ~34,500 GP profit.
Mithril Bars (Mid-Level, Balanced)
- Fee: 72,000 GP (60+ Smithing)
- Mithril Ore: 3,600 bars x 160 GP = 576,000 GP
- Coal: 7,200 coal x 140 GP = 1,008,000 GP
- Stamina: 60,000 GP
- Total Cost: ~1,716,000 GP
Selling 3,600 mithril bars at 700 GP each = 2,520,000 GP, netting ~804,000 GP profit.
Gold Bars (High XP, No Profit)
- Fee: 72,000 GP
- Gold Ore: 5,400 bars x 375 GP = 2,025,000 GP
- Stamina: 60,000 GP
- Total Cost: ~2,157,000 GP
Selling 5,400 gold bars at 100 GP each = 540,000 GP, losing ~1,617,000 GP but gaining 370,000 XP/hour with Goldsmith Gauntlets.
Maximizing Profits and Minimizing Costs
To get the most out of the Blast Furnace, consider these strategies:
Use a Coal Bag and Ice Gloves
A coal bag (150K GP from Motherlode Mine) and ice gloves (free from the Ice Queen) are game-changers. The coal bag doubles your coal per trip, and ice gloves let you grab bars instantly without a bucket, saving inventory space and time.
Pre-Load Coal
Start each session by loading 27 coal into the furnace. This ensures your first ore batch smelts immediately, avoiding delays—crucial for high-tier bars like adamant or rune.
Hop Worlds to Save GP
Deposit ores on a non-Blast Furnace world, pedal them into the pot, then hop to a Blast Furnace world to collect bars. This skips the 72,000 GP/hour fee, though it’s slower and less practical for profit runs.
Hybrid Smelting for XP and GP
Combine gold ore with mithril, adamant, or rune. For example, smelt 26 gold ore + 26 coal (via coal bag), then alternate with mithril trips. This balances XP (200K/hour) and profit (~500K-700K/hour), offsetting gold’s loss.
Is the Blast Furnace Worth It?
The Blast Furnace’s value depends on your goals. For XP, it’s unmatched—gold bars with Goldsmith Gauntlets hit 370K XP/hour, far surpassing traditional methods. For profit, mid-to-high-tier bars like mithril (750K+ GP/hour) or rune (1M+ GP/hour) make it lucrative, despite the upfront costs.
Pros of Blast Furnace
- High Efficiency: Half coal usage and bulk smelting save time and resources.
- Scalability: Works for all Smithing levels with adjustable costs.
- Community Hub: Blast Furnace worlds are active, offering a social experience.
Cons to Consider
- Initial Investment: Fees and supplies can deter low-GP players.
- Attention Required: It’s not AFK; you need to stay focused.
- Market Risks: Profit depends on GE prices, which can crash.
In conclusion, the Blast Furnace cost in OSRS ranges from 545K GP/hour for basic iron smelting to over 2M GP/hour for gold XP runs, with profits peaking at 1M+ GP/hour for rune bars. Whether you’re chasing 99 Smithing or a fat stack of gold, understanding these costs and optimizing your setup will make your Keldagrim trips worthwhile. Grab your coal bag, stock up on stamina, and smelt your way to success!