Last updated: December 26, 2025
How to Calculate Weight Loss Percentage
Quick answer: Weight-loss % = (Starting Weight − Current Weight) ÷ Starting Weight × 100. Use the calculator below for instant results, weekly pace, and progress to goal. Then see the examples and tips to keep your momentum going.
Weight-Loss Percentage Calculator
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The Formula (With Examples)
Weight-loss % = (Starting − Current) ÷ Starting × 100. ¹ Units don’t matter (lb or kg) as long as both are the same.
Example (lbs): Start 185 lb → Current 172.5 lb. Change: (185 - 172.5) = 12.5 lb. % loss = 12.5 ÷ 185 × 100 = 6.8%.
- Example (kg): Start 84 kg → Current 80 kg. Change: (84 - 80) = 4 kg. % loss = 4 ÷ 84 × 100 = 4.8%.
What’s a Healthy Pace?
- A steady weight loss of about 1–2 lb per week (0.45–0.9 kg/week) is generally easier to maintain long term, though the appropriate rate varies by individual and context. ²
- Sufficient protein intake and resistance training help preserve lean mass and support strength during energy restriction. See our Top 10 Health Tips.
- Use our Calorie Calculator to set a small, sustainable deficit and adjust using 10–14 day averages.
Troubleshooting Stalls
Weight-loss stalls are common. Here’s how to troubleshoot—fast:
Water weight, not fat: Sodium, stress, or hormones, etc. can hide progress.
→ Use 7–14 day averages and measurements, not daily scale swings.Decrease Calories: If you're weight has plateaued for a couple weeks, consider slightly decreasing calorie intake. Do not go below 1200 kcal. ³
→ Recalculate and adjust by −100–200 kcal/day or add a bit of activity.Tracking drift: Small extras (oils, snacks, drinks) add up.
→ Tighten tracking for a few days as a reset.Low protein or no lifting: Can slow metabolism and stall fat loss.
→ Prioritize protein and 2–3×/week resistance training.Sleep & stress: Poor sleep and high stress increase hunger and water retention.
→ Aim for 7–9 hours and basic stress management.
Related Reading
- Calorie Calculator: Find Your Daily Needs
- How Long Does It Take to Notice Weight Loss?
- Carbs & Weight Loss: Make Them Work
- Are Protein Bars Good for Weight Loss?
- Healthy Lifestyle Hacks
FAQs
How do I calculate weight-loss percentage?
Use (Starting − Current) ÷ Starting × 100, or the calculator above.
Does it matter if I use lb or kg?
No. Percentage is unit-agnostic—just use the same unit for both numbers. You can switch units in the calculator at any time.
What’s a good weekly loss?
About 0.5–1.0% of body weight per week works for many people. Smaller, steadier changes are easier to maintain.
How often should I weigh in?
Daily or a few times per week, then use a 7–10 day average to smooth normal water fluctuations.
Why did my % jump without changing food?
Water shifts from sodium, soreness, menstrual cycle, and sleep can move the scale a few pounds. Look at weekly averages, not single days.
References:
1. Hatoum IJ, Stein HK, Merrifield BF, Kaplan LM. Advantages of percent weight loss as a method of reporting weight loss after Roux-en-Y gastric bypass. Obesity (Silver Spring). 2013;21(8):1519-25.
2. Nutrition.gov. Interested in Losing Weight? U.S. Department of Agriculture.
3. Mayo Clinic. Weight loss plateau: Why weight loss stalls.
Disclaimer: This page is for general information only and isn’t medical advice. If you have medical conditions or take medications that affect fluids or appetite, work with your clinician.
