Invoice Calculator

Calculate invoice totals with multiple line items, tax, and optional discounts. Perfect for freelancers and small businesses.

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Invoice Total
Subtotal
Discount
Tax

How to Use This Calculator

  1. Enter the Quantity and Unit Price for each line item.
  2. Enter the applicable Tax Rate (VAT, GST, or sales tax).
  3. Optionally enter a Discount % to apply to the subtotal.
  4. The calculator shows subtotal, tax amount, and invoice total.

Formula

Subtotal = Σ (Quantity × Unit Price)

Discounted Subtotal = Subtotal × (1 − Discount%/100)

Tax = Discounted Subtotal × (Tax Rate / 100)

Total = Discounted Subtotal + Tax

Example

Invoice: 1 × $500 + 2 × $150. Tax rate 10%, discount 5%.

  • Subtotal = $500 + $300 = $800
  • Discount = $800 × 0.05 = $40
  • Tax = ($800 − $40) × 0.10 = $76
  • Total = $760 + $76 = $836

Frequently Asked Questions

  • Sum all line items (quantity × price) to get the subtotal. Apply any discount to the subtotal. Then add tax on the discounted subtotal to get the final total.
  • Tax is typically applied after discounts. This calculator subtracts the discount from the subtotal first, then calculates tax on the remaining amount.
  • This calculator supports up to 3 line items. For more complex invoices, expand the "More options" section to access all item fields.
  • Yes. Simply enter the appropriate VAT or GST rate for your jurisdiction in the Tax Rate field. The currency symbol is for display only.

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