Invoice Calculator

Calculate invoice totals with line items, tax, discount, and payment terms.
$
%
%
Discount Type

Subtotal

$100.00

Total Due

$108.25

Line Items

Service or product (1 x $100.00)$100.00

Invoice Summary

Subtotal$100.00
Tax (8.25%)$8.25
Total Due$108.25
Due DateJune 28, 2026

Use the Invoice Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.

How It Works

Our Invoice Calculator streamlines your billing process, ensuring accurate totals for goods or services rendered. In 2026, with an average small business invoicing 2.7 times per week, efficient calculation of line items, tax (e.g., 7.5% state sales tax), discounts, and clear payment terms is crucial for maintaining healthy cash flow and client relations.

The calculator sums individual 'Line Item Totals' (Quantity x Unit Price), then applies any 'Discount' as a percentage or fixed amount to the subtotal. Subsequently, 'Tax' is calculated on the discounted subtotal (or pre-discount subtotal, depending on jurisdiction and user preference) and added, along with any 'Shipping/Handling' fees, to arrive at the 'Grand Total Due'.

Always double-check your tax rate, as these can vary significantly by state and locality in 2026 (e.g., California's statewide sales tax is 7.25%, but local additions can push it higher). A common mistake is misapplying discounts before or after tax, which can lead to under or overcharging. Clearly state payment terms (e.g., 'Net 30' or 'Due on Receipt') to avoid collection delays.

Example: Web Development Project Invoice

  1. 1 Input: 20 hours of Web Design at $95/hour, 10 hours of SEO Consultation at $120/hour. Discount: 5% for early booking. Sales Tax: 6.8% (for a hypothetical state in 2026). Shipping/Handling: $0. Payment Terms: Net 15.
  2. 2 Calculation: (20 * $95) + (10 * $120) = $1900 + $1200 = $3100 (Subtotal). Discount: $3100 * 0.05 = $155. Discounted Subtotal: $3100 - $155 = $2945. Tax: $2945 * 0.068 = $200.26.
  3. 3 Intermediate Result: Subtotal before discount: $3100. Discount amount: $155. Tax amount: $200.26.
  4. 4 Final Result: Grand Total Due: $2945 + $200.26 = $3145.26. Payment of $3145.26 is due within 15 days of the invoice date.

Source: SBA — Business Guide · Last updated: April 2026

Frequently Asked Questions

What should a professional invoice include?
Essential elements: your business name and contact info, client name and address, unique invoice number, date issued and payment due date, itemized list of services/products with quantities and rates, subtotal, tax, total due, and payment terms.
What are standard invoice payment terms?
Common terms: Net 30 (due in 30 days, the most common), Net 15, Net 60, Due on Receipt (immediately), and 2/10 Net 30 (2% discount if paid within 10 days). Freelancers often use Net 15 or Due on Receipt.
How do I handle sales tax on invoices?
List the subtotal first, then add applicable sales tax as a separate line item showing the rate and amount. Some services may be exempt from sales tax depending on your state. Always include your sales tax permit number if required by your state.

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