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Enterprise8 min readApril 1, 2026

Train Custom AI Models for Your Specific Document Types

Prebuilt models extract generic fields. Custom models extract YOUR fields — CPT codes, GL accounts, AIA pay apps, or other domain data. How to train one.

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Prebuilt OCR models are great for standard invoices and receipts. But what about medical superbills with CPT codes and modifiers? Or construction AIA pay applications with retainage percentages? Or your company's unique internal forms? That's where custom model training comes in.

Prebuilt vs. Custom Models

Prebuilt models extract generic fields: vendor name, total amount, date. Custom models extract domain-specific fields that matter to your business: CPT codes, ICD-10 diagnoses, GL accounts, cost centers, project numbers, authorization numbers, and any other structured data unique to your document types.

How Training Works

  1. Collect 10-50 sample documents — Mix different vendors, formats, and variations of the same document type.
  2. Define your fields — Specify exactly what data you want extracted: field names, types (string, number, date, table), and where they typically appear.
  3. Label the training data — Draw bounding boxes around each field in your sample documents and assign labels.
  4. Train the model — Azure Document Intelligence trains a neural model in 10-30 minutes. Neural models handle variable layouts (invoices from different vendors); template models work for fixed-layout forms.
  5. Test and iterate — Upload new documents and verify extraction accuracy. Add more training documents to improve weak areas.

Accuracy by Training Set Size

  • 10 documents: ~85% field-level accuracy
  • 50 documents: ~93% accuracy
  • 200 documents: ~97% accuracy

Continuous Improvement

The best custom models improve over time. Corrected documents are added to the training set and the model is retrained, keeping earlier versions so a weaker one can be rolled back. ScanThisText doesn't retrain anything: on an Enterprise team account, when you fix a field on a scanned invoice or receipt, your latest fixes for that document type are shown to the AI as examples the next time it reads one of yours.

Get Started

ScanThisText doesn't offer custom model training. Its Business plan pulls fields out of invoices, contracts and insurance forms with prebuilt Azure AI models and Claude, so there's nothing to label or train.

Stop retyping invoices — and get paid for the work while you’re at it.

Start a free 14-day Business trial

More Guides

Train Custom AI Models for Document Extraction | ScanThisText.com