What this oni rocket calculator does
Planning space runs in Oxygen Not Included can be tricky: one extra cargo module can push your rocket from a comfortable round trip into a stranded mission. This oni rocket calculator gives you a quick way to estimate fuel, oxidizer, tank count, and travel time before you launch.
The tool is designed as a practical planning aid. It uses a simplified model for burden and engine behavior so you can make fast decisions while building out your space program.
How the calculator works
1) Total travel distance
We start with your one-way distance in hexes, multiply by mission count, and optionally double it for a return trip. Then we add your safety margin. This creates a buffered distance target to avoid under-fueling.
2) Burden adjustment
Burden modules represent the extra weight and complexity from rocket modules (cargo bays, science modules, etc.). In this model:
- Fuel consumption increases by 6% per burden module.
- Rocket speed decreases by 4% per burden module (with a lower bound so speed never collapses unrealistically).
3) Fuel and oxidizer estimate
Each engine has baseline fuel use per hex and, where applicable, an oxidizer ratio. The calculator multiplies those baseline values by adjusted travel distance and burden multiplier to return the total required resources.
Engine assumptions used in this tool
These are simplified planning values intended for quick strategy decisions:
- CO2 Engine: Low speed, low complexity, no oxidizer.
- Steam Engine: Reliable mid-game option, no oxidizer.
- Petroleum Engine: Strong all-rounder with oxidizer demand.
- Hydrogen Engine: Fast late-game travel with oxidizer support.
- Radbolt Engine: Uses radbolts instead of fuel/oxidizer pair.
Example mission plan
Suppose you are launching a petroleum rocket to a 20-hex destination, with 5 burden modules, and you want a return trip plus 20% safety:
- Distance target = 20 × 2 × 1.2 = 48 effective hexes
- Burden multiplier = 1 + (5 × 0.06) = 1.30
- Fuel required = effective hexes × adjusted fuel-per-hex
- Oxidizer required = fuel required × oxidizer ratio
This gives you a conservative loading target and reduces failed sorties due to fuel shortfall.
Tips to improve your ONI rocket efficiency
Reduce burden where possible
Extra modules are useful, but every module hurts speed and efficiency. Build mission-specific rockets rather than one-size-fits-all designs.
Use a healthy safety margin
10-20% is usually a good starting range. If your colony relies heavily on one launch, use a larger margin.
Pick engine by mission profile
- Short scouting trips: CO2 or Steam can be enough.
- Frequent mining routes: Petroleum provides strong flexibility.
- Long-distance logistics: Hydrogen often wins on transit speed.
Final note
ONI systems can change with updates and DLC balancing. Treat this calculator as a fast mission planning companion and calibrate with your in-game observations. If your designs have unusual module setups, add extra safety margin and run one test mission before scaling.