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How to Measure Fat Loss (Not Just Weight) — And Why It Matters More Than You Think

May 4, 2025
4 minutes
Weightloss
How to Measure Fat Loss (Not Just Weight) — And Why It Matters More Than You Think

If you've ever stepped on the scale and felt confused or frustrated by the number staring back at you… you're not alone. The truth is, weight loss isn't always fat loss — and the scale doesn't tell the full story.

That’s why in this guide, we’re breaking down the real numbers that matter, like how to calculate your weight loss percentage, the difference between 1lb of fat vs 1lb of muscle, and how to use simple tools like our calorie calculators or a good old-fashioned measuring tape to track progress in a way that actually makes sense.


Why “How Much Weight You Lost” Isn’t the Whole Picture

Let’s bust a myth real quick: Muscle does not weigh more than fat. A pound is a pound. But muscle is denser, which means 1lb of muscle takes up less space than 1lb of fat. So even if the number on the scale hasn’t moved much, you might be losing inches, building shape, and getting stronger.

That’s why it helps to track:

  • Tape measurements (waist, hips, thighs)

  • How your clothes fit

  • Progress photos

The more ways you measure progress, the less discouraged you’ll be by daily scale fluctuations.


How to Calculate Weight Loss as a Percentage

If you’re someone who needs a bit more structure to feel motivated, this one’s for you.

Here’s the formula:

Weight Loss % = (Starting Weight − Current Weight) ÷ Starting Weight × 100

So, if you started at 200 lbs and now weigh 180 lbs: (200 - 180) ÷ 200 × 100 = 10% of your body weight lost

People search for this in lots of ways:

  • “How do I calculate my weight loss percentage?”

  • “How to figure out percentage of body weight lost?”

  • “How do you work out percent weight loss?”

Same formula. If maths isn’t your thing, just use a calculator (or ask us—we love numbers).


Active Calories vs. Total Calories (and Why It Matters)

Ever wonder why your Apple Watch or Fitbit shows two different calorie numbers?

Here’s the difference:

  • Active Calories = the energy you burn from movement (walking, workouts, chores, etc.)

  • Total Calories = active calories + what your body naturally burns at rest (your BMR)

If you’re trying to create a calorie deficit to lose fat, you need to look at both. Your TDEE (Total Daily Energy Expenditure) gives you the full picture—and our TDEE Calculator makes it super easy to figure out.


How Many Calories Does It Really Take to Lose Fat?

You’ve probably heard that burning 3,500 calories = 1lb of fat. It’s a useful estimate, but keep in mind:

  • Fat loss is gradual

  • Your body adapts over time

  • Hormones, sleep, and stress all affect how fat is stored and burned

You might wonder:

  • “Can I burn 1,000 calories a day?”

  • “How many steps to burn 500 calories?”

  • “Is 1000 calories burned in a workout too much?”

Quick reference:

  • Walking 10,000 steps burns ~400–500 calories

  • Moderate workouts: ~300–600 calories

  • Breastfeeding? Yep, you’re burning ~300–500 calories/day too

Use our Calories Burned Calculator to see your personal burn based on your activity and weight.


How to Track Progress Without the Scale

This is where your measuring tape becomes your best friend.

Here’s what to measure every 2–3 weeks:

  • Waist (smallest part)

  • Hips (widest part)

  • Thighs

  • Arms

Track these numbers in a note or spreadsheet and pair them with progress photos. That way, even if the scale holds steady, you can see the change happening.

We like to call it the tape measuring test — and it’s a game-changer for staying motivated when your weight loss slows down.


A Quick Note on Conversions (Because We’ve All Googled Them)

If you’ve ever searched:

  • “How many kg is 198 lbs?”

  • “Calories to kilojoules?”

  • “How many calories in a kcal?”

Here’s a cheat sheet:

  • 1 lb = 0.45 kg

  • 1 kg = 2.2 lbs

  • 1 kcal = 1 Calorie (yes, they’re the same!)

  • 1 Calorie = 4.184 kilojoules


Final Thoughts: Fat Loss Isn’t Just About Maths

If you’re showing up for yourself, eating well most of the time, moving your body in ways that feel good, and tracking progress from more than one angle — you’re doing it right.

Forget perfection. Progress is what we’re here for.

Need help building a plan?

  • Find your TDEE

  • Track your burn

  • Set your protein goals

You’ve got the tools — now just keep going. We’re cheering you on, every step of the way.