Strategic Bombardment Calculator(Created 7 April 2017)(Updated 20 November 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 civilian structures. A more detailed calculation of conventional blast effects is below, using the charge weight equivalence in TNT run through a nuclear weapons effects calculator to get the 20 PSI radius.

 Bomb Type Charge Wt (lbs) Explosive Charge Charge TNT Equivalence Charge TNTEquiv. Wt. (lbs) 20 PSI Damage Radius (meters) 50 lb GP (British WWII) 12.5 TNT 1 12.5 5 120 lb GP (British WWII) 30 TNT 1 30 7 250 lb GP (British WWII) 72.5 TNT 1 72.5 9 500 lb MC (British WWII) 140 TNT 1 140 11 1000 lb MC (British WWII) 330 Amatol 0.91 300.3 14 2000 lb HC (British WWII) 1400 Amatol 0.91 1274 23 4000 lb HC (British WWII) 3040 Amatol 0.91 2766.4 30 8000 lb HC (British WWII) 5440 Amatol 0.91 4950.4 36 12000 lb HC (British WWII) 9600 Amatol 0.91 8736 43 12,000 lb MC (British Tallboy) 5200 Torpex 1.3 6760 40 22,000 lb MC (British Grand Slam) 9136 Torpex 1.3 11876.8 48 250 lb LD-GP Mk 81 96 Tritonal 1.18 113.28 10 500 lb LD-GP Mk 82 192 Tritonal 1.18 226.56 13 1000 lb LD-GP Mk 83 445 Tritonal 1.18 525.1 17 2000 lb LD-GP Mk 84 945 Tritonal 1.18 1115.1 22

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.
• During WWII, the 8th Air Force had an inflight abort rate of about 8.85%, plus a further 2.67% of all aircraft were shot down before the target area, for a total system reliability of 0.8847 for a B-17.
• Redstone IRBM: 85.57% Flight Reliability (83 successes, 14 failures).
• Atlas A ICBM: 37.5% Flight Reliability (3 successes, 5 failures).
• Atlas B ICBM: 60% Flight Reliability (6 successes, 4 failures).
• Atlas C ICBM: 50% Flight Reliability (3 successes, 3 failures).
• Atlas D ICBM: 78.79% Flight Reliability (104 successes, 28 failures).
• Atlas E ICBM: 54.55% Flight Reliability (18 successes, 15 failures).
• Atlas F ICBM: 76.47% Flight Reliability (52 successes, 16 failures) (Program Goal of 85%)
• Titan I ICBM: 77.61% Flight Reliability (52 successes, 15 failures) (Originally rated 50% reliable, rating raised to 70% with final squadrons).
• Titan II ICBM: 95.06% Flight Reliability (129 successes, 19 failures) (Originally rated about 72.5% reliable, rating raised to 90% with final squadrons).
• Minuteman ICBM: 97.1% Flight Reliability (836 successes, 25 failures).
• Peacekeeper ICBM: 98.04% Flight Reliability (50 successes, 1 failure).
• Polaris IRBM: 99.37% Flight Reliability (628 successes, 4 failures). (Originally rated at <50% reliable for A-1, raised to 63-65% for A-2 and finally 79-82% with A-3.)
• Poseidon IRBM: 97.01% Flight Reliability (260 successes, 8 failures).
• Trident I ICBM: Incomplete data so not given.
• Trident II ICBM: 97.27% Flight Reliability (178 successes, 5 failures).
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.
• During World War II, it was estimated that US aerial bombs had a dud rate of between 10 to 20%. By Vietnam, it was around 5%.
• In 1965, the W47 Y2 Mod 2 which made up about 75% of the W47 stockpile, had a dud rate of about 75%. This meant that crudely, the overall W47 stockpile would only work 50% of the time. To correct this problem, the AEC began rebuilding the whole stockpile of W47s (some 300 warheads), beginning in March 1965 to the W47 Y2 Mod 3 configuration. This fix was not achieved until late 1967.

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
Effectiveness of Bombs, ww2aircraft.net
Explosive Equivalencies, Wikipedia

Circular Error Probable (CEP): (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):