Invoice Total Calculator
Turn hours and a rate into a clean invoice total — with an optional discount and sales tax applied in the right order.
Written by Dorothy Ibrahim, 10+ years in banking & finance
Loading calculator…
How we calculate this
This calculator turns billable hours (or a quantity) and a rate into the exact amount to put on a client invoice. It applies any discount to the subtotal first, then calculates sales tax on the discounted amount — the order tax authorities expect and that invoicing software follows. Most freelance services are not taxed, so the tax field usually stays at zero.
The formulas
- Subtotal
- hours (or quantity) × rate
- Discount
- subtotal × discount%Applied to the subtotal before tax.
- Sales tax
- (subtotal − discount) × tax%
- Invoice total
- subtotal − discount + sales tax
Worked example
- With the defaults — 40 hours at $75/hour — the subtotal is 40 × $75 = $3,000.
- No discount is applied, so the discounted amount stays $3,000.
- No sales tax is applied (0%), which is correct for most freelance services.
- The invoice total is $3,000.
Rates, benchmarks & sources
- Discount is applied to the subtotal before sales tax is calculated. — General invoicing practice (discount-before-tax ordering)
- Whether a service is subject to sales tax depends on the state and service type. — State departments of revenue (rules vary by state)
Figures current as of 2026-07-02. See our methodology & editorial standards for how constants are versioned and verified.
What this tool doesn’t model
- Does not determine whether you must charge sales tax — that depends on your state and service type; the rate is a manual input.
- Assumes a single rate and quantity; itemized multi-line invoices with different rates are not modeled.
- Does not track invoice numbers, payment terms, or partial payments.
Frequently asked questions
Do freelancers charge sales tax on invoices?
Usually not — most states do not tax professional services like design, writing, or consulting. Some states tax certain services, and physical goods are often taxable. Leave the tax rate at 0 unless you have confirmed your state and service type require it.
Is a discount applied before or after tax?
Before. You discount the subtotal first, then calculate any sales tax on the reduced amount. This tool follows that order, which is how tax authorities expect it and how most invoicing software works.
What should a freelance invoice include?
A unique invoice number, your business name and contact info, the client details, itemized work with quantities and rates, the subtotal, any discount and tax, the total due, payment terms (like net 30), and accepted payment methods.
Should I invoice by the hour or a flat fee?
Either works — this calculator handles both, since you can enter quantity × rate. Hourly billing is transparent for open-ended work; flat fees reward efficiency and give clients budget certainty. Many freelancers set a flat project fee derived from an hourly estimate.