How Much Weight Can You Lose In A Month? (The Science-Based Answer)

Do you want to know how much weight you can lose in a month?

Of course you do. Everyone trying to lose weight, build muscle, or reach any similar goal wants to know how fast they can do it and how long it will take them.

So, let’s figure it out right now…

The Difference Between “Weight” And “Fat”

In order to accurately determine how much weight you can lose in a month, we need to first understand the important difference between losing weight and losing fat.

Losing “fat” means… losing fat. Simple enough.

But “weight” can be a lot of different things. For example…

  • Fat.
  • Muscle.
  • Water.
  • Glycogen.
  • Poop.
  • Stomach content.
  • Blood.
  • Hair.
  • Bone.
  • Etc.

Why does this matter, you ask? Because…

You Can Lose “Weight” Really Fast

Weight loss can happen quite fast.

For example… you can cut off a leg and you’ll lose a bunch of “weight” instantly. Hooray!!

More realistically (and slightly less insane), you can also lose a ton of water weight really fast.

This is a fact that many stupid fad diets and useless “cleanses” and “detoxes” are built around. They promise rapid weight loss results and then have you do things that result in significant (and temporary) water loss while claiming it’s body fat. You then regain that water weight soon after and end up right back where you started.

How exciting.

This is also why professional fighters who need to make weight for their fight will sometimes sit in a sauna before their official weigh-in. It’s so they can temporarily lose a bunch of water weight (not fat) really fast.

In addition to water loss, you could also lose weight by losing muscle… something most people want to avoid at all costs.

Hell, you could get food poisoning and poop your brains out and you’ll drop a few pounds within a few minutes.

The point I’m getting at here is that if you want to know how much weight you can lose in a month – and you don’t care what the source of that weight is – the answer to the question becomes: potentially a lot.

But We’re Asking The Wrong Question

If you’re reading this, I’m going to assume that you aren’t interested in losing temporary water weight, you don’t want to lose any lean muscle mass, you don’t have “explosive diarrhea” on your to-do list, and you’re not comfortable with the idea of cutting off a leg (smart move).

And in that case, the one and only thing we’re really talking about when we ask this question is body fat.

So, with this important distinction made, we can now rephrase the question a bit.

Instead of asking how much weight you can lose in a month, let’s make it…

How Much Fat Can You Lose In A Month?

Now this is a question we can more accurately answer. All we need are two simple facts and some easy math.

Fact #1

A caloric deficit is the sole cause and requirement of fat loss.

This means that in order to lose any amount of fat, you need to either eat fewer calories, burn more calories, or do some combination of the two so a consistent deficit exists.

Additional details here…

Fact #2

There are approximately 3500 calories in 1 pound of body fat.

This means that for every 3500-calorie deficit you have, you can expect to lose about 1 pound of body fat.

Please note, however, that you shouldn’t expect to lose exactly 1 pound of “weight” in this scenario, as those other factors I listed earlier (water, poop, stomach content, etc.) will throw off the number on the scale to some extent (e.g. you may lose 1lb of fat but gain 0.5lb of water, so the scale will only show a loss of 0.5lb).

Plus, factors like NEAT (non-exercise activity thermogenesis) and TEF (thermic effect of food) are changing all the time in ways that affect exactly how many calories you end up burning each day.

Having said that, estimating that you’ll lose about 1 pound of weight for every 3500-calorie deficit you create is still the best method we have for estimating how much weight you can lose in a given period of time.

Additional details here:

The Math: How Much Will You Lose In A Month?

With these two facts in mind, all that’s left to do is calculate how much of a deficit you’ll have over the course of a month.

Here are some examples.

Example #1

Let’s say some example person needs to eat 2500 calories a day in order to maintain their current weight (again, this is just an example… you can figure out how many calories you need to eat a day here).

Now let’s say they start eating 2000 calories per day instead.

2500 – 2000 = a 500-calorie deficit each day.

In this scenario, our example person can expect to lose about 1 lb per week. Why? Because a 500-calorie deficit per day x 7 days in a week = 3500 calories.

Pretty simple, right?

Now let’s expand this example to a month instead of a week.

Since there are about 4 weeks in a month, this example person could expect to lose about 4 pounds in a month.

Example #2

Now let’s pretend our example person decided to create a larger deficit.

In addition to eating 500 fewer calories, they also burn 250 more calories via exercise like cardio.

Now they have a total deficit of 750 calories per day instead of 500.

How much weight can they expect to lose in a month now? About 6 lbs.

Example #3

What if our example person went with a 1000-calorie deficit each day?

They’d lose about 8 lbs in a month.

Your Deficit Determines Your Rate Of Weight Loss

I think you can probably see by now that the speed at which you lose fat/weight is determined by the size of your deficit.


  • The smaller your deficit is, the less weight you can expect to lose in a month.
  • The larger your deficit is, the more weight you can expect to lose in a month.

From there, the not-completely-perfect-but-still-accurate-enough “3500-calorie deficit = 1 pound lost” equation will help you narrow things down and get a decently accurate estimate for how much weight you can expect to lose in a given period of time.

And that brings us to an important question…

How Fast Should You Try To Lose Weight?

Once you understand the simple math behind weight loss and that adjusting your calorie intake/output can make progress happen faster or slower, you might begin to think…

“I’ll create a HUGE deficit so I can lose weight as FAST as possible!!!”

I hear ya.

But the problem with this line of thinking is that there’s a lot more to successful weight loss than just being able to do it quickly.

So while it’s tempting to go on some excessively low calorie diet (e.g. 1200 calories a day) and/or start burning some excessively high number of calories, that’s not what you should actually do.

Why not, you ask? Just off the top of my head…

That’s basically a list of everything you should be trying to avoid during weight loss, and attempting to do things as fast as possible will cause and/or worsen 100% of them.

And that brings us back to the question at hand: how fast should you try to lose weight?

Here’s what I recommend…

The Ideal Rate Of Weight Loss (Per Week)

Aim to lose between 0.3% – 1% of your total body weight per week. In most cases, this works out to be somewhere between 0.5-2lbs lost per week.

As I explain in Superior Fat Loss, this is the sweet spot for getting fat loss results that are healthy, sustainable, and still realistically fast WHILE simultaneously minimizing or preventing the MANY problems that come about during the fat loss process (like the stuff I listed a minute ago).

How Much Is That Per Month?

To apply this recommendation in terms of how much weight you should ideally lose in a month, just multiply the weekly rate by 4 (since there are about 4 weeks in a month).

In most cases, you’re looking at between 2-8lbs lost per month.

What’s Next?

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About Jay
Jay is the science-based writer and researcher behind everything you've seen here. He has 15+ years of experience helping thousands of men and women lose fat, gain muscle, and build their "goal body." His work has been featured by the likes of Time, The Huffington Post, CNET, Business Week and more, referenced in studies, used in textbooks, quoted in publications, and adapted by coaches, trainers, and diet professionals at every level.