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Invoice Ontology

Models seller-issued invoices (professional services and usage-based billing) requesting payment for goods or services. Used to generate new realistic invoices with parties, line items, tax treatment, totals and payment instructions.

finance · 33 concepts · 38 relationships · by @ssergienko · CC BY 4.0

Classes (7)

Invoice
The root document requesting payment for delivered goods or services.
e.g. INVOICE · TAX INVOICE #NW-00000
Header Block
Identifiers and dates at the top of the invoice.
e.g. Invoice no, Issue date, Due date
Seller / Issuer
The party issuing the invoice and receiving payment.
e.g. Willow Brook Design Ltd · Cedar Peak Hosting Inc.
Buyer / Customer
The party billed.
e.g. Contoso Outdoor GmbH · Fabrikam Robotics LLC (account 10000)
Line Items
Itemised charges, credits and fees.
e.g. Logo design – 3 concepts · Object storage 12.5 TB-month
Totals Block
Subtotal, tax, total and balance summary.
e.g. Subtotal, VAT, TOTAL DUE · Subtotal, Sales tax, Total, Balance due
Payment Instructions
How and when to pay.
e.g. IBAN and BIC · auto-charged to card ending 0000

Dimensions (4)

Payment Method
Mechanism for settlement.
e.g. bank transfer · card auto-charge
Billing Model
Basis of charges.
e.g. fixed-fee project · usage-based subscription
Tax Regime
Jurisdictional tax treatment.
e.g. EU reverse charge · US state sales tax · UK VAT
Domestic vs Cross-border
Whether seller and buyer are in different countries.
e.g. UK to Germany · US domestic

Properties (17)

Invoice Number
Unique identifier of the invoice.
e.g. 2026-0587 · NW-70318
Issue Date
Date the invoice was issued.
e.g. 3 October 2026 · 2026-09-30
Due Date
Date payment is due.
e.g. 2 November 2026 · 2026-10-30
Billing Period
Period covered by usage-based or recurring charges.
e.g. 2026-09-01 to 2026-09-30
Currency
Currency of all amounts.
e.g. GBP (£) · USD ($) · EUR
PO / Account Reference
Buyer-side reference for matching.
e.g. PO-00000 · account 10000
Tax / VAT ID
Registered tax identifier of a party.
e.g. GB000000000 · DE000000000
Address
Postal address of a party.
e.g. 10 Example Street, Bristol BS1 0AA, UK · 500 Sample Ave, Denver, CO 80202, USA
Line Description
Text describing the item or service.
e.g. Packaging mock-ups · Support plan – Business
Quantity and Unit
Amount of units billed.
e.g. 2 days · 7,200 instance-hours
Unit Price
Price per unit.
e.g. £1,200.00 · $0.096
Line Amount
Extended amount for a line.
e.g. £2,400.00 · -$45.00
Tax Line
Tax rate, label and amount.
e.g. VAT 0% reverse charge · Sales tax (Colorado 2.9%): $29.25
Total / Balance Due
Final payable amount.
e.g. £5,100.00 · $1,037.95
Payment Terms
Stated payment period and late-payment conditions.
e.g. Net 30 · Late interest 8% above base rate
Payment Status
Amount already paid and balance outstanding.
e.g. Amount paid: $0.00
Contact / Support
Contact for billing queries.
e.g. [email protected]

Values (1)

Credit Line
Negative line item such as SLA credit or discount.
e.g. service-level credit (incident 2026-09-14)

Constraints (4)

Arithmetic Consistency
Line amounts equal quantity × price; subtotal is sum of lines; total = subtotal + tax − payments.
e.g. 691.20 + 262.50 + 100 − 45 = 1,008.70
Date Consistency
Due date follows issue date by the payment term; billing period precedes issue date.
e.g. 3 Oct → 2 Nov
Single Currency
All amounts use one currency matching the seller's jurisdiction or contract.
e.g. £ throughout
Tax Legal Basis
Zero-rated or exempt lines cite the legal basis.
e.g. Article 196 Directive 2006/112/EC