Before comparing quantities, confirm the item and specification, choose a common comparison unit and record a conversion factor backed by a checkable source. Retain the original quantity and unit alongside the converted result. Then compare ordered, received and invoiced quantities. A missing factor stays unknown; do not assume every bag or pack contains the same amount.
1. Start with the item and the source document’s unit
A number without a unit is not a comparable quantity. A PO might show 24 bags, receiving 20 bags and an invoice 0.50 metric tons. Those numbers alone do not establish a discrepancy. First establish the bag contents and the meaning of the invoice unit.
Check the item code or precise description, material, specification and pack version. The same commercial name may have different pack sizes. A bag conversion for one item does not automatically apply to another, and a pallet does not represent a fixed number of units without verified contents.
Create a working record with document and line reference, source quantity, source unit, comparison unit, conversion factor, factor source and calculated result. This is a proposed team worksheet. Working in a common unit does not require changing the supplier’s original document.
2. Verify the conversion factor and its direction
A definition such as “one bag of item A contains 25 kg” lets you calculate kilograms by multiplying the bag count by 25. To convert kilograms back to bags, divide by 25. Write the relationship with both units so the factor 25 cannot be confused with its inverse, 0.04.
Evidence can be an approved pack specification, the label for the supplied item or supplier confirmation identifying that item. Record the date and reviewer. If pack contents change between deliveries, use the factor applicable to each receipt instead of applying a new factor retrospectively.
Oracle documents item-specific factors between a transaction unit and an item’s primary unit. This supports the importance of item identity and conversion direction in Oracle’s system; it does not establish automatic pack conversion in Novapro.
Further reading: Oracle: item-specific unit-of-measure conversions
3. Worked example: three documents, one comparison unit
This fictional example contains no customer data. The PO is for 24 bags of one material, with a verified specification of 25 kg per bag. Receiving records 20 checked bags. The invoice bills 0.50 metric tons. Assume billing for received quantities, with no returns or previous charges.
Use kilograms as the comparison unit. The PO is 24 × 25 = 600 kg. Receiving is 20 × 25 = 500 kg. One metric ton is 1,000 kg, so the invoice is 0.50 × 1,000 = 500 kg. In this example, invoice quantity matches receiving. Four bags, or 100 kg, remain against the PO.
Do not add 20 bags and 500 kg as two receipts: they represent the same receipt. Conversion also does not approve quality, price or payment. It makes the quantity comparison explicit.
- If the invoice showed 0.60 metric tons, it would represent 600 kg: a 100 kg difference from documented receiving. Check supporting documents and billing terms before deciding; do not immediately conclude that the invoice is wrong.
- If a US document says only “ton,” clarify whether it means a metric ton or a short ton. They are different units. This example explicitly uses metric tons; do not substitute another ton conversion.
| Source | Original quantity and unit | Calculation in kg | Quantity finding |
|---|---|---|---|
| Purchase order | 24 bags | 24 × 25 = 600 | Quantity ordered |
| Documented receipt | 20 bags | 20 × 25 = 500 | Quantity received in the example |
| Invoice under review | 0.50 metric tons | 0.50 × 1,000 = 500 | Matches the receipt quantity |
| PO balance | 4 bags | (24 − 20) × 25 = 100 | Open balance, not another receipt |
Further reading: NIST: conversion factors by quantity type
4. Check price basis, rounding and missing conversions
The price unit must match the quantity being multiplied. For illustration, a price of 40 currency units per 25 kg bag equals 1.60 per kg, so 500 kg corresponds to 800 currency units before other charges. These are hypothetical arithmetic inputs, not market prices, a quote or Novapro pricing. Multiplying 500 by the bag price uses incompatible units.
Retain enough precision for the calculation and check the agreed document rounding rule. Displaying 0.5 instead of 0.50 does not change quantity, but rounding a conversion factor too early can affect a total. A rounding difference is not automatic approval: document it and use the established review rule.
Converting cubic meters to kilograms requires an applicable density or other measurement basis. Converting length to area requires relevant dimensions. There is no universal factor for every material. If the specification or verified factor is missing, mark the comparison as unresolved and obtain it; do not enter zero or one merely to complete the check.
5. Keep a record the next reviewer can reproduce
Suggested record: item ___, document and line ___, source quantity and unit ___, comparison unit ___, factor and direction ___, source and verification date ___, result ___, difference ___, owner ___, next review ___. Retain the decision with the documents without replacing the source values.
Once units are clear, continue partial-delivery tracking and comparison of the PO, receiving evidence and invoice. Novapro brings purchasing documents into the project context. A demo can examine a sample with different document units and the review process appropriate for your team.
The calculation here is a proposed review method. It does not establish automatic conversion, discrepancy tolerances or payment approval in the system. Matching numbers alone does not replace checking the item, delivery and PO terms.
Practical checklist
- Identify the item, specification and pack contents
- Retain each document’s source quantity and unit
- Define a common comparison unit and correct conversion direction
- Record the conversion source and verification date
- Check price basis and rounding separately
- Assign an owner and review date to differences or missing factors
Prepare a sample without sensitive information: a PO, receiving record, invoice and pack specification. Explore the review workflow in the project context.
Request a document-matching demoFrequently asked questions
Does the same bag count prove quantities match?
Only when the item and verified bag contents are the same. If one document refers to 20 kg bags and another to 25 kg bags, equal bag counts do not represent equal material quantities.
What if the invoice and receiving record use different units?
Retain both source units, verify a factor for that item and calculate both quantities in one comparison unit. Then check which receipts and billing terms the invoice covers. Conversion alone does not approve the charge.
Can we reuse a conversion factor from another project?
Only after verifying that it applies to the same item, specification and pack for the relevant period. An earlier source can support the review but does not replace checking what was actually ordered and supplied.
Keep reading
Three-Way Matching: Purchase Orders, Delivery Tickets and Invoices →
How to Track Partial Deliveries and Delivery Tickets →
Invoice vs. Purchase Order Discrepancies: How to Review and Resolve Them →