Build a PDF invoice generator

Here’s a complete example of a PDF invoice generator using Python with the reportlab library. This script allows you to generate a clean and customizable invoice in PDF format.

🛠️ Prerequisites

Install the required package:

bash
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pip install reportlab

✅ Full Code: PDF Invoice Generator

python
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from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.units import mm
from reportlab.platypus import SimpleDocTemplate, Table, TableStyle, Paragraph, Spacer
from reportlab.lib.styles import getSampleStyleSheet
import datetime

def generate_invoice(invoice_data, filename="invoice.pdf"):
    doc = SimpleDocTemplate(filename, pagesize=A4,
                            rightMargin=30, leftMargin=30,
                            topMargin=30, bottomMargin=18)

    elements = []
    styles = getSampleStyleSheet()

    # Header
    elements.append(Paragraph(f"<b>{invoice_data['company_name']}</b>", styles['Title']))
    elements.append(Paragraph(invoice_data['company_address'], styles['Normal']))
    elements.append(Spacer(1, 12))

    # Invoice info
    invoice_details = [
        ['Invoice Number:', invoice_data['invoice_number']],
        ['Invoice Date:', invoice_data['invoice_date']],
        ['Due Date:', invoice_data['due_date']],
        ['Billed To:', invoice_data['customer_name']],
        ['Customer Address:', invoice_data['customer_address']],
    ]

    for item in invoice_details:
        elements.append(Paragraph(f"<b>{item[0]}</b> {item[1]}", styles['Normal']))

    elements.append(Spacer(1, 12))

    # Invoice Table
    data = [['Item', 'Quantity', 'Unit Price', 'Total']]
    total_amount = 0

    for item in invoice_data['items']:
        line_total = item['quantity'] * item['unit_price']
        total_amount += line_total
        data.append([
            item['description'],
            str(item['quantity']),
            f"${item['unit_price']:.2f}",
            f"${line_total:.2f}"
        ])

    # Add total row
    data.append(['', '', 'Total:', f"${total_amount:.2f}"])

    table = Table(data, colWidths=[80*mm, 30*mm, 30*mm, 30*mm])
    table.setStyle(TableStyle([
        ('BACKGROUND', (0, 0), (-1, 0), colors.HexColor('#d3d3d3')),
        ('TEXTCOLOR', (0, 0), (-1, 0), colors.black),
        ('ALIGN', (1, 1), (-1, -1), 'CENTER'),
        ('FONTNAME', (0, 0), (-1, 0), 'Helvetica-Bold'),
        ('BOTTOMPADDING', (0, 0), (-1, 0), 10),
        ('BOX', (0, 0), (-1, -1), 1, colors.gray),
        ('GRID', (0, 0), (-1, -1), 1, colors.grey)
    ]))
    elements.append(table)

    # Footer
    elements.append(Spacer(1, 20))
    elements.append(Paragraph("Thank you for your business!", styles['Italic']))

    # Build PDF
    doc.build(elements)
    print(f"Invoice saved as {filename}")

# Sample Data
invoice = {
    'company_name': 'Tech Solutions Inc.',
    'company_address': '1234 AI Blvd, Innovation City, 90001',
    'invoice_number': 'TS-2025-001',
    'invoice_date': str(datetime.date.today()),
    'due_date': str(datetime.date.today() + datetime.timedelta(days=30)),
    'customer_name': 'John Doe',
    'customer_address': '789 Market St, Springfield, IL 62701',
    'items': [
        {'description': 'AI Development Services', 'quantity': 10, 'unit_price': 120.00},
        {'description': 'Cloud Hosting (3 months)', 'quantity': 1, 'unit_price': 300.00},
        {'description': 'Maintenance Package', 'quantity': 2, 'unit_price': 75.00}
    ]
}

generate_invoice(invoice)

📄 Output

This script generates a cleanly formatted invoice.pdf file with company and customer details, itemized services, and totals.

Would you like a version that runs as a web app (e.g., using Flask or Streamlit)?