Business
Invoice Calculator
Builds an invoice total, where the terms matter as much as the arithmetic.
Result
Tax is applied after the discount, which is standard in most jurisdictions. Some regions require tax on the pre-discount amount for certain discount types. Check locally.
Get a Free Business AuditHow the calculation works
Line items at quantity times rate, less any discount, plus applicable tax, giving the total due. The terms stated alongside determine when it is paid, and in practice the clarity of the invoice affects collection as much as the terms do.
What moves the number
- Line items and whether they match what was agreed.
- Applicable sales tax on the taxable portion.
- Payment terms and due date.
- Reference details the customer needs to process it.
Where this one goes wrong
An invoice that does not match the agreement, or that lacks the reference a customer's accounts system requires, sits unpaid while nobody treats it as a dispute, which is why the most effective collection improvement is usually invoice accuracy rather than chasing. Get it right first time. Stating a due date rather than payment terms also measurably improves collection, since a date is unambiguous and terms require the customer to calculate.
Before you quote
- Match line items to what was agreed, in the customer's terms.
- State a due date, not just payment terms.
- Include whatever reference the customer needs to process it.
Questions
About this calculator
Why do invoices go unpaid?
Frequently because they do not match the agreement or lack a reference the customer's system requires, so they sit in a queue while nobody treats it as a dispute. Invoice accuracy improves collection more than chasing does.
Should an invoice state terms or a date?
A date, since it is unambiguous while terms require the customer to calculate. It is a small change and it measurably improves collection, because the invoice no longer depends on anyone working out when it is due.
When should an invoice be sent?
Immediately on completion, because the ageing clock starts at the invoice date rather than when the work was done. Days spent not invoicing are days of credit extended that nobody agreed to and nobody is paid for.
Put this calculator on your site
Free to embed. Paste this where you want it to appear. It stays up to date automatically because it loads from BDEVY.
Please keep the attribution line. It is the only thing we ask in return.
How to use this calculator
- Labour ($). Enter your own figure; the page starts at $850.
- Materials ($). Enter your own figure; the page starts at $620.
- Other charges ($). Call-out fee, disposal, permits.
- Discount (%). Enter your own figure; the page starts at 5%.
- Sales tax / VAT (%). Enter your own figure; the page starts at 8.5%.
- Deposit already paid ($). Enter your own figure; the page starts at $400.
The result updates as you type, so you can try a figure, see what it does to balance due, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Labour | $850 |
| Materials | $620 |
| Other charges | $90 |
| Discount | 5% |
| Sales tax / VAT | 8.5% |
| Deposit already paid | $400 |
What comes out
| Result | Value |
|---|---|
| Balance due main result | $1,207.97 |
| Invoice total | $1,607.97 |
| Subtotal after discount | $1,482.00 |
| Tax | $125.97 |
Invoice total $1,607.97 including $125.97 tax. After the 400 deposit, the balance due is $1,207.97.
How sensitive the answer is
Holding everything else steady and changing only labour, this is what happens to balance due. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Labour ($) | Balance due |
|---|---|
| $425 | $769.90 |
| $638 | $989.45 |
| $850 example above | $1,207.97 |
| $1,275 | $1,646.04 |
| $1,700 | $2,084.11 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Labour ($)
- A money amount, starting at $850.
- Materials ($)
- A money amount, starting at $620.
- Other charges ($)
- Call-out fee, disposal, permits.
- Discount (%)
- A percentage, between 0 and 100, starting at 5%.
- Sales tax / VAT (%)
- A percentage, between 0 and 50, starting at 8.5%.
- Deposit already paid ($)
- A money amount, starting at $400.
What the results tell you
| Result | What it is |
|---|---|
| Balance due | The headline result. A money figure. |
| Invoice total | A money figure. |
| Subtotal after discount | A money figure. |
| Tax | A money figure. |
Where these figures usually mislead
Business calculations assume the inputs are steady. Seasonality, a few large customers, and slow payment all break that assumption. A figure that looks healthy annually can still leave you short in a given month.
Keep going
Related calculators
Sales Tax Calculator
Works sales tax, where the rate depends on where the customer is.
Open calculatorVAT Calculator
Works VAT, which a registered business collects and reclaims rather than bears.
Open calculatorDiscount Calculator
Works a discount and what it costs, where the margin effect is the real figure.
Open calculatorGood numbers still need customers
BDEVY builds the marketing, websites, CRM and automation that turn a healthy spreadsheet into a busy schedule. The audit is free and you keep the findings.