Rust Furnace Calculator
Estimate ore, wood, charcoal, and smelting time for Small, Large, or Electric Furnaces.
How to use this furnace calculator in Rust
If you have ever overfilled a furnace with wood, or started smelting only to realize you are short on ore, this tool helps you plan ahead. Enter your target output (metal fragments, sulfur, or HQM), pick the furnace type, and the calculator will estimate your required inputs and total smelt time.
This is especially useful before a raid night, during upkeep prep, or when your team is trying to maximize charcoal production without wasting fuel.
What the calculator estimates
- Ore needed for the selected output.
- Wood required for fuel-based furnaces.
- Charcoal output from burned wood.
- Total smelting time based on your smelting rate and furnace count.
- Stack planning so you can load furnaces faster.
Core Rust smelting ratios used
Output conversion
- Metal Ore → Metal Fragments (1:1)
- Sulfur Ore → Sulfur (1:1)
- HQM Ore → HQM (2:1)
Fuel and speed assumptions
Different servers, updates, or player setups can slightly change practical timing, so this calculator lets you edit both:
- Ore per wood (fuel efficiency)
- Ore per second (smelting speed)
The preset values are reasonable starting points. If your observed in-game numbers differ, just replace them with your own.
Small vs Large vs Electric Furnace
Small Furnace
Great for early-game progression and compact bases. Easy to protect and easy to run, but slower when you are processing huge ore batches.
Large Furnace
Better for clans and late-game material throughput. Run multiple large furnaces to prep sulfur and frags quickly before raid windows.
Electric Furnace
No wood fuel required, so no charcoal output. Excellent for clean, predictable processing if your power grid is stable.
Practical planning tips
- Batch ore by objective: upkeep, raid kits, ammo, or boom crafting.
- Use charcoal forecasts to line up gunpowder crafting efficiently.
- Scale furnace count during off-hours so you are stocked before prime time.
- Record your server's real smelt speed and set it once in this tool.
FAQ
Does this tool replace exact in-game testing?
Not completely. It gives fast planning estimates. For perfect precision on modded servers, run one short test and update the custom fields.
Why is HQM ore different?
HQM uses a 2:1 ore-to-output conversion, so you need double the ore compared to your final HQM amount.
Can I use this for charcoal farming?
Yes. For wood furnaces, the charcoal estimate matches wood consumed, helping you forecast gunpowder pipelines.
Disclaimer: Rust balancing can change over time. Treat this as a planning calculator and adjust settings to match your server and patch.