How to Reconcile Two Business Systems

A useful reconciliation does more than subtract two totals. It defines the population on each side, chooses a reliable match key, classifies missing or duplicate records, controls the dollars, and exposes exceptions.

Define each population

State exactly which records and dates belong in the reconciliation.

Choose the match key

Order number, invoice number, transaction ID, shipment number, or another business key must be normalized consistently.

Compare both directions

Ask what exists in system A but not system B, and what exists in system B but not system A.

Separate timing from true differences

A record can be valid but belong to a different period or process stage.

Prove completeness

Controls should demonstrate that records and dollars did not disappear during processing.