Weights and Measures Compliance Calculator
Determine whether a packaged product's actual net quantity is within the legal tolerance limits defined by NIST Handbook 133 (Checking the Net Contents of Packaged Goods), which is adopted by most U.S. states and many international jurisdictions.
MAE = Maximum Allowable Error. Enter how many packages in the lot exceed the MAE threshold.
Formulas Used
Maximum Allowable Error (MAE):
MAE_value = Labeled_Qty × MAE_rate
MAE_rate (NIST HB 133 Table 2-3, by labeled qty in oz or fl oz):
< 1 oz/fl oz → 9%
1 – <2 → 8%
2 – <3 → 7%
3 – <4 → 6%
4 – <6 → 5%
6 – <16 → 4% (up to 1 lb / 1 pt)
16 – <64 → 3% (1 lb – <4 lb)
64 – <320 → 2% (4 lb – <20 lb)
≥ 320 → 1% (≥ 20 lb)
Individual Package Tests:
MAE Test: Actual ≥ Labeled − MAE_value
Unreasonable Shortage: Actual ≥ Labeled − 2 × MAE_value
Lot Compliance (NIST HB 133 Table 2-5):
Max MAE violations allowed:
n = 1–30 → 2 packages
n = 31–80 → 3 packages
n = 81–200 → 5 packages
n > 200 → 7 packages
Shortfall (%) = ((Labeled − Actual) / Labeled) × 100
Assumptions & References
- Compliance criteria follow NIST Handbook 133 (6th Edition, 2023), Checking the Net Contents of Packaged Goods, adopted by most U.S. states under the Uniform Packaging and Labeling Regulation (UPLR).
- The MAE table applies to both weight and volume commodities; volume quantities are converted to fluid-ounce equivalents for table lookup only.
- The individual package test checks a single package against the MAE threshold. A package below (Labeled − MAE) counts as one MAE violation in the lot tally.
- The unreasonable shortage rule (below Labeled − 2×MAE) is an automatic enforcement action for the individual package, independent of lot averages.
- The lot average test requires the mean net quantity of all sampled packages to be ≥ the labeled quantity; a single-package entry is treated as the mean.
- The lot MAE violation rate uses NIST HB 133 Table 2-5 acceptance numbers.
- This calculator does not account for tare weight errors, temperature corrections for liquids, or commodity-specific exemptions (e.g., random-weight packages).
- International equivalents: EU Directive 76/211/EEC uses similar ±T tolerances; consult local metrology authorities for jurisdiction-specific rules.
- Reference: NIST HB 133 (2023) — https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/hb133