How Long Would Food, Fuel and Ammo Last in the Zombie Apocalypse?

October 29, 2012 in Editorial

At the end is a table. The rest of the article is our logic and workings out. If there are zombies outside now, head straight to the table. Or a rifle. Actually, rifle.

“Gather supplies. Kill Zombies. Repeat.” This is our Zombie Defence Plan at Centives. But we got to wondering just long we could go on gathering food, fuel and ammo before supplies ran out.

First, we looked at fuel. After the apocalypse, chances are petrol will no longer be delivered to gas stations. The idea is generally to drive around emptying what is left of their reserves, before moving on to the next station. How long do supplies last after deliveries stop?

Well, in March 2012 UK petrol delivery drivers went on strike. It turned out that in a fit of panic buying, supplies of fuel ran out in just 2 days; although if they had not panicked, supplies should have lasted about double that time.

No deliveries, panic buying:

About 2 days of fuel. 

No deliveries, not panic buying:

About 4 days of fuel.

But this was without mass-apocalypse casualties reducing demand. The fewer people survive, the more fuel per person there is. If 10% of people are still around after the global catastrophe, there is enough fuel for 40 days of normal usage. 1% survival rate; 400 days usage, and so on. If you think a 1% survivor rate is rather low, then keep in mind that this would put the world population at 70 million, which is greater than what the Roman Empire had. We suspect most of us have a far smaller survival rate in mind when we think ‘apocalypse’.

Petrol usage may decrease if car is surrounded by zombies.

Note however, that we’re assuming that people use their cars in much the same way as they would do pre-apocalypse. People may use vehicles less, but equally they may start using generators, so we believe that consumption rates stay reasonably constant. This is, however, up for debate.

Well we have an estimate of fuel supplies, but presumably food would run out first?

This surprised us, but no.

We have only looked at the warehouses that supply supermarkets, not shop shelves, as warehouses are where most of the food really is. And we believe that there are warehouse supplies of 8.25 days’ worth of foods that are non-perishable. At a 1% survival rate, that is 825 days or a bit over 2 years of food available.

  There are warehouse reservesof 13.5 days of ‘slow moving groceries’, 9.5 days of ‘fast moving groceries’ and 9.5 days of ‘frozen groceries’

Around 75% of total grocery stocks is ‘slow’

About 2/3 of all groceries are non-perishable

Which is considerably longer than the amount of time our fuel supplies would last.

Although alternative means of travel could be explored.

Now as any zombie-hunter knows, food and fuel only get you so far. You may be able to run faster than a braindead shuffler, but eventually you’ll need to take them out and by far the best way to do so is a shot to the head.

Actual ease of access to weapons varies hugely, so we’re only looking at world averages. The World Bank suggests a figure of around 500 million small arms available worldwide. Bearing in mind a global population of 7 billion, this means that your chance of having a weapon is 1 in 14; odds that we don’t really like the sound of. Happily, this figure changes dramatically at a 1% survival rate, where there are around 7 firearms per survivor.

A bigger concern is likely to be ammunition:

Annual ammunition production:

12 billion rounds.

Active military shelf life:

6 months

Global stock:

24 billion rounds

Bullets per person:


But bear in mind that unlike food and fuel, ammunition levels don’t exactly improve with lower population survival. At a 0.1% survival rate, you may have 3,410 rounds per survivor but there are still only 3.41 bullets per zombie. This works out to survivors needing to hit zombies in the head 29.3% of the time or you’ll run out of bullets before you run out of undead.

To summarise, at current consumption levels, fuel runs out about twice as quickly as food, and although weapons are reasonably available on a worldwide average, this depends on your location. A survivor’s biggest problem, unless you’re an excellent shot, is likely to be ammunition.

Percentage of Survivors
Post Apocalypse World Population
Fuel per Survivor
Food per Survivor
Firearms per Survivor
Rounds of Ammunition per Survivor
Rounds of Ammunition per Zombie*
100% 7,047,000,000 4 days 8.25 days 0.071 3.41 N/A
25% 1,761,750,000 16 days 33 days 0.284 13.6 4.54
10% 704,700,000 40 days 82.5 days 0.71 34.1 3.78
1% 70,470,000 400 days 825 days 7.1 340.6 3.44
0.1% 7,047,000 11 years 23 years 71 3,410 3.41
0.01% 704,700 110 years 226 years 710 34,100 3.41
0.001% 70,470 1,096 years 2,259 years 7,100 341,000 3.41
0.0001% 7,047 11,000 years 22,600 years 71,000 3.41 million 3.41
0.00001% 705 110,000 years 226,000 years 710,000 34.1 million 3.41
0.000001% 70 1.1 million years 2.6 million years 7 million 341 million 3.41

*Bear in mind, ‘Rounds of Ammunition per Zombie’; that’s per zombie. Not per survivor. You don’t have 3.41 shots per zombie, worldwide there are 3.41 bullets for every zombie.


Enjoyed this article? You might also enjoy our thoughts on pitched battles against zombies, or the data output generated by the Matrix. You can find those and other interesting things in our Editorials although if you want a selection of our most popular check out the “Greatest Hits“. You might also want to follow us on Twitter or Facebook to get the latest and greatest from Centives.