Invoice calculator
Add your line items, a discount and a tax rate to get the subtotal, tax, total and what is still due.
Free to use, no account needed. What you type stays in your browser.
Invoice total
$942.84
Subtotal
$970.00
Tax
$69.84
Balance due
$742.84
This is what is still to be paid.
Breakdown
- Subtotal
- $970.00
- Discount
- −$97.00
- After discount
- $873.00
- Tax
- $69.84
- Invoice total
- $942.84
This is a calculation, not an invoice. It has no invoice number, dates or tax numbers.
How this is calculated
An invoice total is built up in steps. These are the formulas used:
- Subtotal
- S = Σ (q × p)
- Discount
- D = S × d ÷ 100
- Tax
- X = (S − D) × r ÷ 100
- Total
- T = S − D + X
- Balance due
- T − P
q is the quantity, p is the unit price, S is the subtotal, d is the discount percent, D is the discount, r is the tax rate, X is the tax, T is the total and P is the amount already paid. A fixed discount replaces D and cannot be more than S.
Quantity times price is calculated exactly and rounded to the cent for each line. The discount and the tax are then each rounded to the cent. Every step is rounded, so the figures shown add up exactly. Your accounting software may round at a different step, so a difference of a cent is possible.
This tool only does the arithmetic. A valid invoice in your country may need an invoice number, dates, seller and buyer details, tax registration numbers and specific wording. Check the rules that apply to you, or ask an accountant.
Worked example
Two lines, 10 × 85 and 1 × 120, give a subtotal of $970.00. A 10% discount takes off $97.00, and 8% tax on the rest adds $69.84, so the total is $942.84. With $200.00 already paid, $742.84 is still due.
Invoice questions
Is this a legal invoice?
No. It only calculates the amounts. A legal invoice usually needs more, such as an invoice number, dates, seller and buyer details and tax numbers. The rules differ by country, so check them or ask an accountant.
How do I add shipping or a service fee?
Add it as its own line with quantity 1. Lines are discounted and taxed like everything else, so if shipping should not be taxed, work out the tax on the other lines first.
Is the tax added after the discount?
Yes. The tax is worked out on the amount left after the discount. Check that this matches the rule where you sell. If your prices already include tax, use the VAT/GST calculator instead.
How is rounding done?
Each line is rounded to the cent (half up), then the discount and the tax are rounded to the cent. Accounting programs may round in a different place, so a cent of difference is possible.
Is my information stored or sent anywhere?
No. The calculation runs in your browser. The numbers and descriptions you enter are not sent to us or saved.
Related calculators
- VAT / GST calculatorAdd VAT or GST to a price, or take it out of a price that already includes tax. Enter your own rate.
- Discount calculatorFind the price after a discount, or work out the discount percentage from the original and sale price.
- Commission calculatorWork out the commission on your sales, or find how much you need to sell to earn a target commission.
Results are estimates for planning. They are not financial, tax or religious advice.