Does it matter if I use pounds or kilograms?

No. Percentage is unit-agnostic—just use the same unit for both numbers. The calculator lets you switch units anytime.

Why did my percentage change without changing my food?

Water shifts from sodium, soreness, menstrual cycle, and sleep can move scale weight short term. Look at weekly averages, not single days.

How to Calculate Weight Loss Percentage — Free Calculator & Examples

Q: How do I calculate weight-loss percentage?

Use (Starting − Current) ÷ Starting × 100, or the on-page calculator.

Q: What’s a healthy weekly rate of weight loss?

Roughly 0.5–1.0% of body weight per week works for many people. Smaller, steadier changes are easier to sustain.

Q: How often should I weigh in?

Weigh daily or a few times per week and use a 7–10 day average to smooth normal water fluctuations.

Last updated: September 15, 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

Your Results

Enter your numbers to see weight-loss %.

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The Formula (With Examples)

Weight-loss % = (Starting − Current) ÷ Starting × 100. Units don’t matter (lb or kg) as long as both are the same.

Example: Start 185 lb → Current 172.5 lb. Change = 12.5 lb. % loss = 12.5 ÷ 185 × 100 = 6.8%.
Example (kg): Start 84 kg → Current 80 kg. Change = 4 kg. % loss = 4 ÷ 84 × 100 = 4.8%.

What’s a Healthy Pace?

Many people do well with ~0.5–1.0% of body weight per week at most, or about 0.5–2.0 lb/wk (0.2–0.9 kg/wk) depending on size and context.
Protein & strength help preserve muscle while losing fat. 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

Track for 7–10 days (weekends too). Measure oils, dressings, nut butters.
Average your scale weight across the week to smooth water shifts (sodium, hormones, soreness).
Adjust one dial: reduce portions by ~100–200 kcal/day or add 2–3k steps/day. Re-check in 10–14 days.
Hydrate smart: alternate plain water with a light electrolyte mix—see Electrolytes: Best Water Supplements.

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.

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.