How do you calculate underfeed risk?

Weight severity at 0.40, occurrence at 0.35, and detection at 0.25, then sum. With severity 6, occurrence 4, and detection 3 the weighted risk score is 4.55.

How is this different from a standard RPN?

A classic FMEA multiplies severity, occurrence, and detection for an RPN up to 1000. This uses a weighted average that keeps the score on the same 1-10 scale and lets you emphasize severity, which for underfeeding of actives is usually the biggest concern.

What is a high underfeed risk score?

On a 1-10 scale, scores above roughly 6-7 warrant immediate control changes, 4-6 are watch items, and below 4 are generally acceptable. The example 4.55 sits in the mid watch band.

Why weight severity highest?

An underfed active ingredient can make product ineffective or non-compliant regardless of how often it happens, so severity carries the largest 0.40 weight. A rare but catastrophic underfeed still deserves attention.

How do I lower the score?

Reduce occurrence with gravimetric control and lot-change recalibration, and reduce detection difficulty with in-line checkweighing or mass-flow verification. You usually cannot change severity, so attack the other two terms.

Underfeed risk vs overfeed cost: which first?

Tackle underfeed risk first where severity is high, because a spec failure or recall dwarfs material giveaway. Use overfeed cost to prioritize among low-severity, high-cost ingredients.

Weighing, Dosing & Loss-in-Weight Feeding calculator

Underfeed Risk Calculator

Underfeed risk scores the danger that a loss-in-weight or dosing feeder delivers less material than the recipe requires, using an FMEA-style weighting of severity, occurrence, and detection. Underfeeding an active ingredient, catalyst, or additive can put product out of spec, weaken a formulation, or trigger a recall, so quality and process engineers use this to rank which feeders need tighter control first. Unlike overfeed, which mainly costs money, underfeed threatens the product itself. The single weighted number makes it easy to compare feeders and target the worst offenders.

What this calculator does

Underfeed risk scores the danger that a loss-in-weight or dosing feeder delivers less material than the recipe requires, using an FMEA-style weighting of severity, occurrence, and detection.
Use it when underfeed risk in weighing, dosing and loss-in-weight feeding needs a defensible ranking against other weighing, dosing and loss-in-weight feeding risks for the next review.
It combines severity, occurrence, and detection scores with fixed weights into one prioritized underfeed risk number.

Formula used

Underfeed Risk risk score = severity × 0.40 + occurrence × 0.35 + detection × 0.25

Inputs explained

Severity of an underfed dose (impact if it ships):
Occurrence likelihood of underfeeding:
Detection difficulty before shipment:

How to use the result

Use it during feeder FMEAs, control-plan reviews, or after a near-miss to rank which dosing lines need corrective action.
Scores are judgment-based and the weighting is fixed; it ranks relative risk but does not predict an actual defect rate or probability.

Common questions

How do you calculate underfeed risk? Weight severity at 0.40, occurrence at 0.35, and detection at 0.25, then sum. With severity 6, occurrence 4, and detection 3 the weighted risk score is 4.55.
How is this different from a standard RPN? A classic FMEA multiplies severity, occurrence, and detection for an RPN up to 1000. This uses a weighted average that keeps the score on the same 1-10 scale and lets you emphasize severity, which for underfeeding of actives is usually the biggest concern.
What is a high underfeed risk score? On a 1-10 scale, scores above roughly 6-7 warrant immediate control changes, 4-6 are watch items, and below 4 are generally acceptable. The example 4.55 sits in the mid watch band.
Why weight severity highest? An underfed active ingredient can make product ineffective or non-compliant regardless of how often it happens, so severity carries the largest 0.40 weight. A rare but catastrophic underfeed still deserves attention.
How do I lower the score? Reduce occurrence with gravimetric control and lot-change recalibration, and reduce detection difficulty with in-line checkweighing or mass-flow verification. You usually cannot change severity, so attack the other two terms.

Last reviewed 2026-05-12.