Nuclear Weapon Effects: Understanding Blast Radius and Survival
Kurzgesagt's nuclear war videos have hundreds of millions of views. With geopolitical tensions, understanding blast radius, thermal radiation, and fallout zones based on weapon yield has never been more relevant. This educational tool uses declassified physics from Glasstone & Dolan and NUKEMAP methodology to help users understand what happens when a nuclear weapon detonates — and how distance and shelter affect survival.
About This Calculator: Nuclear Weapon Effects
Why: Kurzgesagt's nuclear war content has hundreds of millions of views. With geopolitical tensions, people want to understand blast radius, thermal radiation, and fallout — not from fear-mongering but from education. This calculator provides declassified physics in an accessible format.
How: Enter weapon yield (kilotons), burst type (airburst/surface), burst altitude, your distance, shelter type, and wind conditions. The calculator computes fireball radius, blast overpressure zones, thermal burn radii, radiation dose, fallout zone dimensions, and survival probability.
📋 Quick Examples — Click to Load
📈 Blast Effects by Distance
Overpressure and thermal zones vs. distance from ground zero
📊 Effect Radii Comparison
Fireball, blast, and thermal radii for current yield
🍩 Casualty Zone Distribution
Relative area of each effect zone (proportional to radius squared)
🛡️ Shelter Protection Factor Comparison
Radiation dose reduction by shelter type
⚠️For educational and informational purposes only. Verify with a qualified professional.
Nuclear weapon effects are governed by well-understood physics, much of it declassified since the Cold War. Glasstone & Dolan's "Effects of Nuclear Weapons" and NUKEMAP methodology provide empirical formulas for fireball radius (0.066 × Y^0.4 km), blast overpressure zones (5 psi ≈ 0.28 × Y^1/3 km), and thermal radiation (3rd-degree burns ≈ 0.38 × Y^0.41 km). Kurzgesagt's nuclear war videos have hundreds of millions of views; this calculator helps users understand blast radius, thermal radiation, and fallout zones based on weapon yield — an educational tool for preparedness and awareness.
Sources: Federation of American Scientists, FEMA, Glasstone & Dolan.
Key Takeaways
- • Fireball radius scales as Y^0.4; blast overpressure zones scale as Y^1/3 — doubling yield does not double the destructive radius
- • Airburst maximizes blast and thermal damage over area; surface burst creates massive local fallout
- • Shelter protection factors range from 1 (none) to 500+ (dedicated fallout shelter) — getting inside matters
- • Fallout travels downwind; dangerous zone length ≈ wind speed × 24 hours; width ≈ 20% of length
Did You Know?
How Do Nuclear Effect Formulas Work?
Fireball and Blast
Fireball radius R = 0.066 × Y^0.4 (km), where Y is yield in kilotons. Blast overpressure (5 psi, 2 psi) scales as Y^1/3: R_5psi ≈ 0.28 × Y^1/3, R_2psi ≈ 0.49 × Y^1/3. These formulas come from scaled distance relationships in Glasstone & Dolan.
Thermal Radiation
Thermal (flash) burn radii: 3rd-degree ≈ 0.38 × Y^0.41 km, 1st-degree ≈ 0.67 × Y^0.41 km. Thermal energy scales roughly with yield; distance attenuation follows inverse-square with atmospheric absorption.
Fallout and Shelter
Surface bursts loft debris; fallout plume length ≈ wind speed (km/h) × 24 hours; width ≈ 20% of length. Shelter protection factor (PF) divides dose: PF 10 means 1/10th the exposure. FEMA recommends 24-48 hours minimum shelter time.
Expert Tips
Historical and Modern Nuclear Weapon Yields
| Weapon | Yield | Fireball (km) | 5 psi (km) |
|---|---|---|---|
| Hiroshima (Little Boy) | 15 kt | 0.18 | 0.68 |
| Tactical (W54) | 0.01-1 kt | 0.03-0.07 | 0.06-0.28 |
| W87 (Minuteman III) | 300 kt | 0.58 | 2.0 |
| B83 (Largest US) | 1.2 Mt | 0.95 | 3.2 |
| Tsar Bomba | 50 Mt | 3.8 | 12.8 |
Frequently Asked Questions
How do nuclear weapons work?
Nuclear weapons release energy through fission (splitting heavy atoms like uranium-235) or fusion (combining light atoms like hydrogen). A fission primary triggers a fusion secondary in thermonuclear weapons. The energy is released as blast wave (50%), thermal radiation (35%), ionizing radiation (10%), and residual fallout (5%). Yield is measured in kilotons (kt) or megatons (Mt) of TNT equivalent.
What is an airburst vs surface burst?
An airburst detonates above ground (typically 500-2000m for maximum blast effect). It maximizes overpressure and thermal damage over a wider area but produces minimal local fallout. A surface burst detonates at or near ground level, creating a crater and lofting massive amounts of radioactive debris into the atmosphere, producing dangerous fallout plumes downwind.
How far does fallout travel?
Fallout travels downwind at roughly the wind speed. For a surface burst, the dangerous fallout zone extends about 24 hours of wind travel in length (e.g., 360 km at 15 km/h wind) and typically 20% of that in width. Heavier particles settle first; lighter particles can travel hundreds of kilometers. Radiation intensity decreases with time (7-10 rule: for every 7-fold increase in time, dose rate drops by 10).
What protection do shelters offer?
Shelter protection factors (PF) reduce radiation exposure: none (PF 1), residential building (PF 2-3), basement (PF 10), concrete building (PF 40-100), dedicated fallout shelter (PF 200-1000). A PF of 10 means you receive 1/10th the dose. FEMA recommends staying sheltered at least 24-48 hours after detonation, then evacuating if necessary.
How big are modern nuclear weapons?
Modern arsenals range from tactical weapons (0.3-50 kt) to strategic warheads. US W88 (Trident) is ~475 kt; W87 (Minuteman III) ~300 kt; B83 bomb ~1.2 Mt. Russian RS-28 Sarmat can carry multiple 800 kt MIRVs. The largest ever tested was the Tsar Bomba at 50 Mt (1961). Most strategic warheads are 100-800 kt for optimal blast efficiency.
What should you do during a nuclear attack?
Get inside the nearest substantial building immediately. Go to the center or basement, away from windows. Stay inside for at least 24-48 hours. Listen to emergency broadcasts. If outdoors when the flash occurs, take cover behind anything solid within seconds; lie flat to reduce thermal exposure. Do not look at the flash. After the blast, avoid fallout by staying sheltered until authorities advise.
Key Statistics
Official Data Sources
⚠️ Disclaimer: This calculator provides estimates based on declassified physics formulas (Glasstone & Dolan, NUKEMAP methodology). Actual effects depend on terrain, weather, building construction, and many other factors. This is an educational tool for understanding nuclear weapon effects — not a substitute for official emergency guidance. Consult FEMA and local authorities for preparedness information.