Nuclear War Simulator for Windows

Project summary and purpose

Nuclear War Simulator is a free simulation built by Ivan Stepanov to portray and visualize large-scale nuclear conflicts with an emphasis on humanitarian outcomes. The tool models realistic exchanges involving the world’s nuclear arsenals — there are more than 13,000 nuclear warheads globally, with over 9,000 held in active military stockpiles — and can be used to explore scenarios involving countries such as Russia, the United States, India, and Pakistan. Its primary aim is to show the human and environmental consequences of nuclear exchange rather than to gamify warfare.

How the simulation is structured

The engine combines many interdependent components to recreate how a nuclear confrontation unfolds. Key systems incorporated into the model include:

• The expected humanitarian effects on civilian populations and infrastructure
• The platforms and methods used to deliver warheads
• The geolocation and movement of forces and assets
• The command, control, and decision-making chains that govern employment

By linking these layers together, the simulator produces a dynamic picture of how strikes and counter-strikes might cascade across regions.

What physical effects are modeled

Damage and post-detonation phenomena are calculated across a dense population grid. The simulator accounts for:

• Radioactive fallout distribution and deposition patterns
• Shockwave overpressure and its destructive radius
• Intense thermal pulses from detonations
• The secondary role of widespread fires and how population concentrations alter casualty outcomes

These calculations are rendered quickly so users can see immediate summaries of impact and follow-up effects.

User controls and scenario options

You can build and run custom conflict scenarios with considerable flexibility:

• Place individuals, families, or communities on the map to estimate survival probabilities
• Configure nuclear inventories to reflect historical, current, or hypothetical arsenals
• Adjust timing, escalation dynamics, and whether an initial first strike occurs
• Specify aiming accuracy and blast parameters using measures such as circular error probability and overpressure thresholds

Simulations execute rapidly and provide numeric and visual outputs for planning and analysis.

Community additions and example mods

The project supports community-created modifications to expand scenarios or introduce new mechanics. One notable user mod stages a confrontation between China and the United States: it begins with a large-scale cyber operation against U.S. infrastructure and escalates to a U.S. nuclear response launched from three Ohio-class ballistic missile submarines operating in the Pacific. Mods like this demonstrate how the base simulator can be adapted to explore many plausible crisis narratives.

Visualization and results

During playback, the map updates to show evolving radiation levels, casualty estimates, and fallout zones. Together, these layers give a stark visualization of the aftermath of nuclear exchanges and highlight how interconnected systems produce catastrophic humanitarian consequences.

Suggested alternative

If you want another free option to compare, consider COLDLINE — a no-cost alternative that some users recommend.