Strategic Bombardment Calculator
(Created 7 April 2017)
(Updated 8 April 2017)

Green = User input boxes.
Red = System output boxes.

NOTES:

Circular Error Probable (CEP): This is the radius in which 50% of all weapons launched/fired/dropped would land. The 95% Radius (R95) is the radius in which pretty much all weapons would land. Converting to/from R95 to CEP is very simple: Multiply R95 by 0.48 to get CEP. Divide CEP by 2.1 to get R95.

Probability of Kill (PKill): Calculation defaults assume an 85% PKill desired against the target. This is a good balance between "target destruction assurance" and "bouncing the rubble".

Lethal Radius: For conventional weapons, the lethal radius has been set to a default assumption of 15 meters, which is a good rule of thumb for 500 pound GP bombs against a variety of targets. If you were to change it to a different type of bomb (2000 lb AP) or a different type of target (bunker), the Lethal Radius would change significantly.

For Nuclear Weapons, the Lethal Radius (LR) of various yields is dependent on the target hardness levels. A good rule of thumb for Nuclear LR's is below:

Nuclear Target Type

Hardness
(PSI)

20 KT Lethal Radius (m)

100 kt Lethal Radius (m)

200 kt Lethal Radius (m)

1 MT Lethal Radius (m)

2 MT Lethal Radius (m)

5 MT Lethal Radius (m)

10 MT Lethal Radius (m)

20 MT Lethal Radius (m)

Class 1 Target
(Very Hard Target)

5,000

77

132

166

284

358

485

611

770

Class 2 Target
(Hard Target)

2,000

105

179

225

385

485

659

830

1045

Class 3 Target
(Medium Hard Target)

500

166

284

358

611

770

1045

1317

1659

Class 4 Target
(Soft Target)

25

450

770

970

1659

2091

2838

3575

4504

Class 4 and it's attendant 25 PSI are not cited in the CBO study -- they are a reasonable extrapolation of target category classifications. Additionally, 20 PSI is enough to ensure near total 100% fatalities and destruction of almost all concrete structures; so it's good enough to stand in for an urban area in calculations.

If you need to compute a Lethal Radius for a specific nuclear weapons system, use the following inputs below:

Yield of weapon: kilotons and Target Hardness of: PSI. results in a Lethal Radius of meters.

System Reliability: This is the percentage of a chance that the weapon system will successfully function and reach the target area. NOTE: It is worth noting that in general public sources, the 17 October 1963 launch of a MINUTEMAN I was classified as a "success". This launch, classified CEDAR LAKE, was part of the Operational Test (OT) preceding induction of the Minuteman into SAC SIOP service and it actually missed the target by 24.26 nautical miles to the right and 781.37 nautical miles over.

Weapon Reliability: This is the percentage of a chance that the bomb/missile will successfully explode after it's been released at/near the target.

Bibliography:
Trident II missiles: capability, costs, and alternatives, Congressional Budget Office
Missile Procurement, Air Force, May 16, 1961 Hearings, AlternateWars.com.
Calculations relevant to Nuclear Exchanges, Big Book of Warfare
Wikipedia, CEP

Circular Error Probable (CEP): (m)
Lethal Radius (LR): (m)
System Reliability: (%)
Bomb/Weapon Reliability: (%)
Bombs/Weapons Per System:       

Desired Target PKill: (%)

Single Shot Prob. of Kill (SSPK): (%)
Terminal Prob. of Kill (TKP): (%)

Planes/Weapons Systems Needed:       
Bombs/Weapons Needed:       
Bombs/Weapons On Systems:       
Spare Bombs/Weapons:       

Kill Probability (KPN):       

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