>The simple relationship E=mc2 tells us that 2.3 kg mass was converted to energy in the bomb, but a hydrogen fusion reaction only converts about 0.7% of the starting mass to energy. So they would have had to burn through at least 330 kg of hydrogen, and they probably started with much more since the efficiency of fusion won't be 100%.

>According to wikipedia, high yield nuclear weapons produce something like 5 megatons per metric ton of material, which would mean the Tsar Bomba had about 10,000 kg of hydrogen.

Just to interpret the comment:

2.3 kg is the mass of hydrogen which is converted to pure energy in a 50 MT bomb (which is roughly the yield of the Tsar Bomba, the largest bomb ever detonated). Eg. the total mass of bomb material after detonation is 2.3 kg less than the starting mass.

330 kg is the absolute minimum amount of hydrogen which would have been present in the above bomb based on 0.7% of it being converted to energy. But a real bomb would likely contain significantly more due to other inefficiencies.

10,000 kg is the estimate of the actual quantity of hydrogen in the Tsar Bomba.

Also keep in mind just asking how much material is used in a bomb is like asking how long a piece of string is. The above discussion was about a 50 MT bomb, but the largest weapon currently in the US arsenal, the B83, has a maximum yield of 1.2 MT and a total mass of 1100kg (not just hydrogen). Most are smaller than that. The W76, used on submarine missiles, is only 95 kg total with a 0.1 MT max yield.

>how much hydrogen is actually used in a hydrogen bomb

That's not going to be public knowledge, and a lot of those back-of-the-envelope sort of calculations end up making unfounded assumptions, so i's not a surprise that answers differ so wildly.