Percent Weight Change Calculator
Calculate percent weight change for malnutrition screening and assessment. A clinical tool for registered dietitians with time-based analysis, significance alerts, and documentation-ready output.
Weight Change Analysis
Clinical Significance
Assessment will appear here.
Documentation Output
Weight Change Assessment: Usual Weight: -- Current Weight: -- Weight Change: -- Percent Change: --% Time Frame: -- Clinical Significance: --
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Clinical Use Note
This calculator is designed to assist registered dietitians and healthcare professionals in assessing weight changes as part of a comprehensive nutrition assessment. Weight change should be evaluated alongside other clinical indicators.
Significant Weight Loss Criteria
According to ASPEN/AND malnutrition consensus criteria:
| Time Frame | Significant Loss | Severe Loss |
|---|---|---|
| 1 Week | 1-2% | >2% |
| 1 Month | 5% | >5% |
| 3 Months | 7.5% | >7.5% |
| 6 Months | 10% | >10% |
| 1 Year | 10% | >20% |
Frequently Asked Questions
How is percent weight change calculated?
Percent weight change is calculated as: ((Usual Weight - Current Weight) / Usual Weight) × 100. A positive result indicates weight loss, while a negative result indicates weight gain.
What is "usual body weight"?
Usual body weight (UBW) is the patient's typical, stable weight when healthy. It's more reliable than ideal body weight for assessing changes. If UBW is unknown, use the most recent documented weight or patient-reported weight from when they were healthy.
When is weight loss clinically significant?
Weight loss is clinically significant when it exceeds established thresholds relative to time: >1-2% in 1 week, >5% in 1 month, >7.5% in 3 months, or >10% in 6 months. These thresholds indicate potential malnutrition risk requiring intervention.
How does this relate to malnutrition diagnosis?
Percent weight change is one criterion in the ASPEN/AND malnutrition consensus. Other criteria include inadequate energy intake, loss of muscle mass, loss of subcutaneous fat, fluid accumulation, and diminished functional status. Multiple criteria are needed for diagnosis.
Should I consider weight gain as well?
Yes, unintentional weight gain can also be clinically significant. Rapid weight gain may indicate fluid retention (edema), medication effects, or metabolic changes. Weight gain in previously malnourished patients should be monitored as part of refeeding.