oxygen not included calculator

How this Oxygen Not Included calculator helps

In Oxygen Not Included, most colony failures are not caused by one dramatic event—they happen because of small deficits that compound over time. Oxygen production is a classic example. If your colony produces just a little less oxygen than it consumes, breathable gas slowly thins out, duplicants lose productivity, and the whole base starts to spiral.

This calculator gives you a fast planning check: how much oxygen your colony needs, how much your current setup can deliver, and whether you have enough production headroom to survive interruptions and expansion.

Base assumptions used in the calculator

The formula uses common base-game values:

• Duplicant oxygen need: 100 g/s each
• Oxygen Diffuser output: 500 g/s oxygen
• Electrolyzer oxygen output: 888 g/s oxygen
• Electrolyzer hydrogen byproduct: 112 g/s hydrogen
• Diffuser algae use: 550 g/s algae
• Electrolyzer water use: 1000 g/s water
• Power draw (both buildings): 120 W each at full uptime

Uptime inputs are important. In real colonies, machines are often blocked by pressure, disabled by automation, or temporarily starved for resources. Uptime lets you model realistic average output instead of ideal output.

How to use this tool effectively

1) Enter your current colony size

Set duplicants first, then include any extra oxygen demand (for example, known losses from venting mistakes or intentional off-base use assumptions).

2) Add a safety margin

A margin of 10% is a practical baseline. Higher margins are useful when your colony is expanding quickly, your power grid is unstable, or your oxygen rooms are not fully automated yet.

3) Model production with uptime, not theory

If your electrolyzer room cycles on and off due to pressure or intermittent water, enter a lower uptime (for example 70–85%). This gives you a realistic oxygen budget.

4) Read the net oxygen status

If the result is a deficit, the calculator also estimates how many additional diffusers or electrolyzers would close the gap.

Quick planning example

Suppose you have 12 duplicants, one electrolyzer running at 85% uptime, and no diffusers.

• Demand: 12 × 100 = 1200 g/s
• Supply: 1 × 888 × 0.85 = 754.8 g/s
• Result: deficit of 445.2 g/s before margin

That colony will eventually suffocate without additional production or better uptime. Adding one diffuser at full uptime (+500 g/s) would barely cover the raw deficit, but margin and downtime risk still suggest improving electrolyzer stability.

Diffusers vs electrolyzers: when to use each

Oxygen Diffusers

• Great in early game
• Simple setup and low complexity
• Consumes algae, which is finite in many maps

Electrolyzers

• Best long-term scalable oxygen source
• Consumes renewable water (with proper infrastructure)
• Produces hydrogen, which can be captured for power

A common progression is to start with algae-based oxygen, then transition to electrolyzer systems once your plumbing and power become stable.

Common oxygen math mistakes

• Ignoring uptime: A machine that is "installed" is not always producing.
• No safety margin: Exact balance can fail due to temporary outages.
• Forgetting expansion: New duplicants instantly increase baseline oxygen demand.
• Ignoring resource chains: Oxygen production is only as reliable as algae/water logistics.

Practical checklist for stable oxygen

• Target positive oxygen flow with at least 10% surplus.
• Track algae and water availability by cycle, not by current storage snapshot.
• Use gas pumps, vents, and automation to reduce overpressure downtime.
• Keep power stable so oxygen systems are on critical circuits.
• Re-run calculations whenever population changes.

Final thoughts

A good oxygen plan is less about one perfect build and more about maintaining margin under imperfect conditions. Use the calculator as a recurring checkpoint: before printing new duplicants, before switching food strategies, and before major construction phases. If your oxygen budget is healthy, almost every other colony system becomes easier to manage.