Korea Prepackaged Goods Net Quantity Sampling Calculator

Compare individually measured net quantities, sample averages and T1/T2 deficiencies against Korean lot inspection criteria.

Internal lot-review tool using Korean rules for 2026. Initial values are a fictional 500 g product, 100-package lot and 49 samples. Enter all masses in grams and confirm only what you have actually verified.

1. Product, lot and scale

Product group in Decree Annex 1

Selecting a group does not establish legal scope. Confirm the general mass method below.

Nominal quantity Qn (g)

>0 to 50,000 g · up to 3 decimals

Lot size N (packages)

Integer: 1 to 1,000,000,000

Scale measurement uncertainty U (g)

From calibration records · >0 to 5,000 g · up to 3 decimals

Scale division d or e (g)

>0 to 5,000 g · both U and d must be below 0.1T · up to 3 decimals

Table 8 mapping: explicitly listed N = 100, 200, …, 1,000, or N ≥ 1,500. Other lot sizes are withheld pending sampling-plan confirmation; no automatic rounding.

2. Paste sample measurements

One row per sample: gross mass then tare (g)

Example: 522 20 → 502 g net. Paste two spreadsheet columns separated by tabs. Use 2–100 rows, each value 0–100,000 g with up to 3 decimals. No commas, units or blank interior rows; gross must be at least tare. The sample count must exactly match the required count.

3. Verify inspection conditions

The selected product uses the general mass method, excluding frozen, drained-solid, multipack, gas/vacuum and medicinal products.Samples were randomly drawn from one actual lot with identical production conditions and nominal quantity; every tare was individually measured.I verified measurement traceability, calibration, checks with M1 or better weights, and the general mass method’s temperature conditions.

Review net quantity before dispatch

Underfilled packages can lead to returns, repacking, repeat deliveries and customer complaints.
Gross weight includes the packaging, and an old tare value can become misleading after a container change.
This calculator organizes individually measured gross and tare masses from a random sample of one production lot.

It compares the sample average, individual deficiencies and the correction specified in the Korean lot procedure.
Results are internal review states: input criteria met, numerical criteria not met, or assessment withheld pending verification.
A numerical pass is not official testing or a legal shipment decision.

Use the report to take the next step

Save the TXT with the original rows, identify the affected sample numbers and remeasure using suitable equipment.
Review filling settings and container changes before deciding action under the site’s quality procedure.

Korean jurisdiction and supported method

This tool uses Korean rules verified for 2026, including the 27 product groups in Enforcement Decree Annex 1.
A listed name alone does not establish applicability: confirm the actual product, its mass declaration and the general mass inspection method.
Use one lot with identical nominal quantity and production conditions.

Supported review

Subtract each package’s individually measured tare from its gross mass.
Enter everything in grams, with nominal quantity greater than zero and no more than 50,000 g.
This is an internal preparation tool for Annex 6 lot sampling.

Excluded methods

Frozen goods, ice-glaze removal, drained solids, multipacks, gas/vacuum packages, LPG and medicines are excluded.
Do not convert volume, length, area or count declarations to mass without the required separate method.

Retail inspection and lot inspection are different procedures.
The retail three-sample and repeat-sampling rules in Article 5 must not be mixed with this lot plan.
The tool does not perform conformity verification.

Prepare the measurement records

Nominal quantity and lot size: use the label’s net quantity and actual number of packages produced under the same conditions.
Sales volume or order quantity is not automatically the inspection lot size.
Gross mass and tare: give each sample a number, record its paired measurements, and check for product left on the emptied packaging.
Uncertainty and division: use calibration evidence and the actual scale division separately.
Display precision is not a substitute for measurement uncertainty.
Procedure confirmations: check random sampling, traceability, equipment checks and temperature conditions.
Leave unverified conditions unchecked.

Paste two columns, gross then tare, separated by spaces, tabs or semicolons.
Use 2–100 rows, each mass from 0 to 100,000 g with at most three decimals, and no commas, unit text, scientific notation or empty interior rows.
Gross mass must be at least tare, and the sample cannot exceed the actual lot.

Lot size, sample size and correction factor

Annex 6 table 8 supplies sample size n, correction factor SCF and the allowed T1 count together.
Identical sample sizes do not justify ignoring the underlying lot row.
Only explicitly listed lot sizes and the range starting at 1,500 are mapped here.

Korean Annex 6 table 8 lot sampling plan
Lot N	Sample n	SCF	Allowed T1
100	49	0.28	3
200	63	0.28	3
300	78	0.26	4
400	80	0.27	4
500	80	0.27	4
600	81	0.27	4
700	82	0.27	4
800	85	0.27	4
900	86	0.27	4
1,000	86	0.27	4
1,500 or more	100	0.26	5

A lot of 100 requires 49 samples; a lot of 200 requires 63.
Do not change an actual lot of 101 to 100, or 1,100 to 1,500, to obtain a result.
Unlisted sizes need an inspection-body sampling-plan decision; deficient or excess sample counts withhold assessment without deleting rows.

Tolerable deficiency T by nominal mass

Enforcement Decree Annex 20 alternates percentage and fixed-mass bands.
Recalculate T when the nominal pack size changes.
Each interval excludes its lower endpoint and includes its upper endpoint, with the first starting above zero.

>0–50 g

9% of nominal

>50–100 g

4.5 g

>100–200 g

4.5% of nominal

>200–300 g

9 g

>300–500 g

3% of nominal

>500–1,000 g

15 g

>1,000–10,000 g

1.5% of nominal

>10,000–15,000 g

150 g

>15,000–50,000 g

1% of nominal

T is not an instruction to reduce the filling target by that amount.
The average requirement remains separate.
The calculator does not round a percentage-derived T upward or add an extra allowance.

Net quantities, individual classes and average

Per package

Qi = gross − individual tare
Ei = Qi − Qn
Deficiency = max(0, Qn − Qi)
T1: Qn − 2T ≤ Qi < Qn − T
T2: Qi < Qn − 2T

Sample statistics

Mean = ΣQi ÷ n
Eave = ΣEi ÷ n
s = √(Σ(Qi − mean)² ÷ (n − 1))
SEL = s × SCF
Corrected comparison = Eave + SEL

Deficiency exactly equal to T is outside T1; deficiency exactly equal to 2T belongs to T1.
Any deficiency above 2T is T2, and even one T2 fails the individual criterion.
T1 must not exceed the allowed count.
Overfilled samples cannot offset this individual-package test.

Nonnegative mean error meets the average requirement.
For negative mean error, add SEL: a positive sum meets the criterion and a negative sum does not.
An exactly zero corrected sum is withheld because the notice specifies positive and negative outcomes without that boundary.
The sample standard deviation uses n − 1, and displayed rounding never controls the decision.

Equipment requirements and workflow

U < 0.1T · d or e < 0.1T

The general mass method requires both uncertainty and scale division to be strictly below one tenth of T.
Verify measurement traceability and checks using M1 or better weights.
The source describes ordinary ambient measurement with 20°C as its reference.

Confirm product and method, then enter the actual nominal mass and lot size.
Enter calibration uncertainty and division in grams.
Record gross and individual tare for the randomly selected samples.
Check only verified conditions and run the comparison.
Read all withheld reasons and both numerical criteria, then save the report.

Uncertainty does not create extra net quantity.
The tool does not add or subtract it to turn a sample into a pass.
If equipment requirements are not met, remeasure with suitable equipment and procedures.

Worked examples and exact boundaries

Constant net quantity

For Qn = 500 g, N = 100 and 49 samples all weighing 522 g gross with 20 g tare, every net quantity is 502 g.
T = 15 g, mean = 502 g, Eave = 2 g, s = 0 g and T1/T2 counts are zero.
The input criteria are met once equipment and procedural conditions are verified.

A slightly low average

With 24 samples at 490 g and 25 at 509 g, the mean is about 499.693878 g.
The sample standard deviation is about 9.596449 g and SEL about 2.687006 g, giving Eave + SEL about 2.380883 g.
There are no T1 or T2 samples, so the numerical criteria are met subject to verified conditions.

For that 500 g pack, 485 g is exactly T below nominal and is within T; 470 g is exactly 2T below nominal and belongs to T1.
469.999 g is T2.
If all 49 samples are 499 g, each small deficiency is within T but s = 0 and the average criterion fails.
These examples explain the arithmetic; they are not filling targets or process-capability standards.

Practical review and limits

After a packaging change

Similar-looking containers can have different masses.
Retain the measured tare for each sample and compare it with the correct gross record.
An apparent fall in net quantity warrants a tare check as well as a filling-machine review.

When a sample is deficient

Use its T1/T2 row number to connect the report to the original record.
Replacing selected deficient samples just to obtain a pass compromises the sampling plan.
Further sampling or rework belongs to the site’s quality procedure and inspection-body guidance.

The calculator does not estimate process capability, the entire lot’s defect rate or financial return losses.
Operator variation and changes during a production run need separate records.
Numerical criteria being met does not resolve an unverified procedure.

Frequently asked questions

Does every package below its label quantity fail?

Check individual deficiency and the sample average separately.
Packages can all be within T while the average criterion still fails.
A high average cannot cancel a T2 package.

Can I get a pass with fewer samples?

Descriptive statistics remain available, but assessment is withheld when the count differs from the required sample size.
Extra rows are not silently discarded either.
Follow the sampling plan established before measurement.

Should an unlisted lot size be rounded up?

No automatic mapping is made.
Table 8 lists specific sizes and the range starting at 1,500.
The source reviewed did not establish an interpolation rule for the gaps.
Ask the inspection body while retaining the actual lot size.

Can I use one container weight for every package?

This tool requires individually measured tares.
The average-tare method has its own conditions and sampling requirements in Annex 6 table 9.
A single container measurement cannot replace those requirements.
Repeated equal values must still be actual individual measurements.

Is a division equal to 0.1T acceptable?

Both measurement uncertainty and the scale division must be strictly below 0.1T under the general mass method.
For Qn = 500 g, T = 15 g, each must be below 1.5 g.
Traceability, calibration and check-weight conditions also need confirmation.

What if negative mean error plus SEL is exactly zero?

The corrected-error wording distinguishes positive and negative values without specifying exact zero.
This tool withholds that boundary for interpretation and measurement review.
An original mean error of zero meets the definition requiring mean net quantity to be at least the nominal quantity.

Does the T1 count tell me how many packages to repack?

It identifies a class within the sample, not a defective count for the whole lot or a legal repacking instruction.
Remeasure the rows and review equipment, tares and filling before deciding further action through your quality procedure and inspection body.

Can I submit the saved file as an official certificate?

The TXT is an internal review of inputs and numerical comparisons.
It does not replace the official form in the notice, conformity verification or shipment approval.
Keep the actual sampling, operator and equipment records needed for formal inspection.

Official sources and verification date

Rule year: 2026; verified September 26, 2026 (2026-09-26).
Current-law search and text were obtained directly from the Korean Ministry of Government Legislation OPEN API.
Original HWP files supplied equations missing from XML.
Recheck product scope, T, sampling plans, equipment and average boundaries after amendments and at least every six months.

Measures Act Article 41: MST280029, effective 2026-03-03.
Enforcement Decree Articles 36–37 and Annexes 1 and 20: MST278291, effective 2025-10-01.
Net Quantity Inspection Criteria for Prepackaged Goods: Notice 2021-126, effective 2021-07-15, Articles 2–6 and Annexes 1 and 6.
Original Annex 1 and original Annex 6: strict equipment inequalities and table 8.

Build a review from your actual measurements

Replace the fictional inputs with the actual lot records.
The TXT preserves inputs, sample rows, numerical results and withheld reasons for comparison with remeasurement.
Editing an input clears the earlier result, so recalculate the final version before saving.
Confirm the current sampling plan with the inspection body and retain equipment and lot records together.

Enter sample measurements