How Many Bed Bugs Are in a Bed – 3 Different Scenarios

Did you know that a female bed bug can lay up to 500 eggs in her lifetime?

That means that even one single pregnant bug can cause a severe infestation if given enough time and food. For example, in a little more than a month, there might already be over a thousand insects living in your bed.

Below you will find a few different scenarios and our calculations. We will also be providing some useful information that will help you estimate the damage on your own.

Signs of a Bed Bug Infestation

First things first, how do you find out whether you even have a bed bug infestation? There are a few signs that will help you find the answer to the question.

Actual bed bugs

Logically, if you see a few insects running around, this might indicate that you have a problem. Unfortunately, even one bug can lead to terrible consequences, in case it’s a pregnant female.

However, you might never see an adult bed bug, if you don’t look for it, as the creatures leave their hiding place only in search of food (and that usually happens at night).

So, make sure to pay attention to other signs as well.

Tip: sometimes bed bugs can get confused with other insects and vice versa. If the creature in front of you has a brown (rusty) body, 6 legs, 2 antennae, a narrow head, and a wide abdomen – then that’s a bed bug. Bear in mind that these insects can’t fly.


In most cases, bites are the first indication of a bed bug infestation. These creatures will feed on any blood that they are able to find. And, usually, it’s the blood of the person sleeping in the bed.

The bug might bite you 3 times in a straight line (some people like to refer to the line as ‘breakfast, lunch, and dinner’). But this is not always the case as one bite is sometimes enough.

People’s reactions to the bite can differ a lot. Some might develop a severe welt, while others wouldn’t have anything at all. Most of the time, the bite looks like a flat reddish welt.

Bloodstains on your sheets

If you tend to frequently change position in your sleep, you might end up crushing a bed bug that had just fed on your blood. This will result in a rusty stain.

If you find a suspicious mark on your sheets, make sure to check your body for any scratches. In case everything is ok and you tend to see these rusty stains quite often – it looks like you have a bed bug problem.

Fecal marks

Such stains are a lot smaller than the ones that we have mentioned before, but you can still notice them. The dark spots look like a dot from a marker.

It is relatively easy to check, whether the mark you see in front of you is actually a fecal stain or not. Simply add some water – the mark won’t wash out, and it’ll start to look like a stain from a magic marker.

Shell casings

Bed bugs go through quite a few life stages. Their shell won’t exactly allow the insects to grow, so before proceeding to the next stage, the bug has to get rid of its previous ‘skin’.

It is easy to find these casings lying around the house. Look for translucent, hollow outlines.


If you have spotted a cluster of grain-like, milky eggs, it means that you’re in trouble. These tiny things can be anywhere but are usually found in crevices of fabric or wood.


Let’s put it this way – if you can feel a specific bed bug odor, it means that the infestation had already gone out of control.

You won’t be able to detect the smell of a single insect, but you’ll start to notice the ‘aroma’ if there are hundreds of bed bugs emitting their pheromones in your bedroom.

The odor is slightly sweet and musty. Some compare the smell to raspberries, while others say that a bed bug infestation smells like coriander.

Bed Bug Life Cycle

During their life, bed bugs go through 7 different stages. It is important to know the creature’s life cycle as it would be easier for you to evaluate the damage, once you come across the actual bugs, their shells, or eggs.


Every female can lay 1-3 eggs per day and anywhere between 200 and 500 eggs in her lifetime. To continue to produce eggs, bed bugs need to eat at least once every 2 weeks.

Baby bed bugs

First stage nymph, second stage nymph, third stage nymph, fourth stage nymph, fifth stage nymph.

Even though these insects are ‘babies’, they will happily bite you and drink your blood just like any other bed bug.

Once the eggs hatch, the babies will go through 5 nymph stages. In order to get to the next stage, the bug needs to have at least one blood meal.

The insect becomes larger with each stage and sheds off its shell casing.

The whole transformation from the 1st stage nymph to an adult can take between 5 weeks and 6 months (it all depends on whether the creature manages to find enough food or not).

Adult bed bug

These insects usually live for around 4-12 months. Though, in some cases, it could be longer than that (about 18 months).

How Many Bed Bugs Are in a Bed – 3 Different Scenarios

Do you want to know exactly how many insects there are in your bed? Here are our calculations for three different scenarios.

Scenario #1: You Have a Single Bed

Every infestation might begin with one single female. So, this will be our starting point.

  • Day 1

1 pregnant female.

  • Day 7

Over 20 bed bugs (nymphs and 1 adult).

  • Day 35

100 adult bed bugs that are ready to reproduce.

  • Day 40

This is where the situation will pretty much get out of control as the females will be producing up to 3 (sometimes even 5) eggs every day.

By the fortieth day, your bed might have over a thousand insects (this will happen in case the creatures were able to eat during the period).

Scenario #2: You Have a Double Bed

For our second scenario, let’s take a double bed and two bed bugs.

  • Day 1

2 pregnant females.

Warning! If you are thinking that there is no way a pregnant female will ever be able to get in your house, you might be wrong. The bugs that are carrying eggs tend to wander around, instead of staying in their hiding place.

  • Day 7

Over 40 bed bugs (2 adults and babies).

  • Day 35

Around 200 insects have become mature (if they lived next to a food source).

  • Day 40

Only after a little more than a month, you might end up with thousands of annoying, blood-sucking creatures in your bed. 

Scenario #3: You Have a Bed with a Mattress Encasement

Getting a mattress encasement is a great way to protect your bed from insects. Even if you already have an infestation, you can use an encasement to get rid of it.

Properly install the mattress protection and finally have a good night’s sleep in your bed – the encasement seals the box spring and mattress and traps all the bed bugs inside.

As a result, the insects will starve to death.

Of course, new bed bugs can try and get into your bed. But because of the encasement, it will be easy to spot the little creatures and git rid of them. The insects simply have nowhere to hide.

Bear in mind that these things will be effective if you manage to get the right size (the encasement has to sit tightly on the mattress). You would have to put a separate encasement on your mattress and your spring box.

Also, do read the product description before making a purchase. The encasement has to be labelled as ‘escape and bite proof’.

If your bedroom is warm, it will take the bed bugs around 14 days to die of hunger.

One more thing you need to know…

Even though bed bugs literally have the word ‘bed’ in their name that does not mean that they live only in this piece of furniture. Unfortunately, the creatures can also be found in sofas, chairs, suitcases, boxes, and any cracks and crevices.

At the end of the day

If you ever wondered how many bed bugs are in a bed, now you know the answer.

Even a single female can cause a large infestation that would be practically impossible to control. By day 40, for example, your bed might already have a thousand (or even more) bed bugs in it.

A special mattress encasement can come in handy in such a situation. If all the bugs had chosen to live only in your mattress and spring box, a proper encasement will help you get rid of these disgusting creatures in 2 weeks or so.

Alright, that’s it for this article, here are a few hand-selected articles that you might also find interesting reads:

Do Stink Bugs Go in Your Bed? 3 Signs Everyone Should Know

Turn Up The HEAT – Do Bed Bug Heaters Work?!

11 Things to Consider When Hiring an Exterminator

Steve Foster

Mad about bugs and wanting to publish as many articles as I can to help educate people about these amazing beautiful creatures! For more info check out my about page

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