Free Invoice Calculators
Free calculators for creating invoices, setting payment terms, calculating taxes and discounts, and managing accounts receivable
What can these 26 calculators do?
They cover the arithmetic that surrounds an invoice: building a total from line items, hours or milestones; pricing work from a markup, a margin or a target income; adding and extracting sales tax, VAT and GST; working out due dates, late fees and interest; and measuring how quickly you actually get paid with DSO, aging and collection metrics.
Every calculator runs in your browser, shows its working, and explains the formula it used. Nothing you type is sent anywhere, and none of them needs an account.
Invoicing
Create & Price
Build invoice totals, hourly rates, and project pricing.
- Invoice CalculatorAdd line items, discounts, tax, and payments to get the invoice total and balance due.Calculate
- Hourly Invoice CalculatorTurn hours and hourly rates into an invoice total, with expenses, discounts, tax, and deposits.Calculate
- Contractor Invoice CalculatorPrice contractor invoices from labor, materials, and job costs.Calculate
- Project Invoice CalculatorInvoice fixed-price or milestone project work with expenses, discounts, tax, and deposits.Calculate
- Markup CalculatorCalculate selling price and profit from cost plus markup percentage.Calculate
- Margin CalculatorCalculate selling price from a target margin, or analyze markup and margin from a price.Calculate
- Freelance Rate CalculatorCalculate the hourly rate you need based on your income goal, expenses, and billable time.Calculate
- Billable Hours CalculatorEstimate annual, monthly, and weekly billable hours after time off and non-billable work.Calculate
- Retainer CalculatorSet a monthly retainer from expected hours and hourly rate, with optional discount and overage pricing.Calculate
Adjustments
Tax & Discounts
Estimate sales tax, VAT, GST, and invoice discounts.
- Sales Tax CalculatorAdd sales tax to a pre-tax amount or remove tax from a tax-inclusive total using any rate.Calculate
- VAT CalculatorAdd VAT to a net amount or remove VAT from a VAT-inclusive total using any VAT rate.Calculate
- GST CalculatorAdd GST to a pre-tax amount or extract GST from a GST-inclusive total using any rate.Calculate
- Invoice Discount CalculatorApply a percentage or fixed discount and see the new invoice total, with optional tax after the discount.Calculate
- Early Payment Discount CalculatorCalculate early-payment terms such as 2/10 Net 30, including savings, payment deadlines, and annualized cost.Calculate
Due dates
Payment Terms & Late Payments
Work out due dates, late fees, and days past due.
- Invoice Due Date CalculatorCalculate invoice due dates for Net 7, 15, 30, 45, 60, 90, and custom payment terms.Calculate
- Business Days CalculatorAdd or subtract business days from a date, or count working days between two dates.Calculate
- Late Payment Fee CalculatorCalculate flat, percentage, or recurring late fees on overdue invoices.Calculate
- Late Payment Interest CalculatorCompute interest accrued on an unpaid invoice balance.Calculate
- Days Past Due CalculatorCount how many calendar days an invoice is past due and which AR aging bucket it falls into.Calculate
Collections
Accounts Receivable
Measure DSO, turnover, aging, and collection performance.
- DSO CalculatorCalculate Days Sales Outstanding to see how accounts receivable compares with credit sales.Calculate
- DSO Improvement / Cash Released CalculatorEstimate cash released when you shorten days sales outstanding.Calculate
- Accounts Receivable Turnover CalculatorCalculate how many times you collect average receivables in a period, and the implied days to collect.Calculate
- Average Collection Period CalculatorCalculate how many days it takes, on average, to collect payment from customers.Calculate
- AR Aging CalculatorEnter outstanding invoices to see current, 1–30, 31–60, 61–90, and 90+ day receivable balances.Calculate
- Collection Effectiveness Index CalculatorScore how much of available receivables you actually collected.Calculate
- Bad Debt Percentage CalculatorCalculate write-offs as a percentage of credit sales or receivables.Calculate
From a calculation to an invoice
A calculator settles a number; an invoice collects it. Once you have the figure, the free invoice generator will build the document around it — line items, tax, terms and a downloadable PDF — and the invoice templates explain what belongs on the invoice for your kind of work.
Frequently asked questions
Are these invoice calculators free?
Yes. Every calculator on this page is free to use, with no signup and no limit. They run entirely in your browser, so the figures you enter are never sent anywhere.
Which calculator should I use to work out an invoice total?
Use the invoice calculator if you are adding up line items with tax and a discount, the hourly invoice calculator if you are billing hours against a rate, or the contractor invoice calculator if you are separating labor from materials on a job.
Do these calculators give tax advice?
No. The tax calculators apply whatever rate you enter — they do not know which rate applies to your sale, and rates vary by country, by locality and by what you sell. Confirm the correct rate and your registration position with an accountant or your tax authority.
Turn the number into an invoice
Fill in your details, add the line items, and download a print-ready PDF. Free, no signup, no watermark.