About PaymentTermsCalculator.com
PaymentTermsCalculator.com is a free tool for calculating invoice due dates and early payment discounts under Net 30 and related payment terms (Net 15/45/60/90). It's published by Gesmine-Invest Limited, a UK-registered company (company number 14120136, registered office Hardy House, 269 Poynders Gardens, London, SW4 8PQ).
Sourcing Methodology
All calculations on this site are deterministic date and financial arithmetic — invoice due date = start date + term days; early payment discount = invoice amount × discount percentage; DSO = (accounts receivable ÷ credit sales) × period days. These are standard, publicly documented formulas, not estimates or survey-derived figures, so there is no sourcing-honesty tradeoff to manage: the numbers are exact given the inputs provided.
The one deliberate simplification: business-day mode excludes weekends only, not federal holidays. We chose this to avoid depending on a yearly-maintained holiday calendar, which would need annual updates to stay accurate. Always confirm exact terms against your own contract when a due date falls near a public holiday.
Monetization Disclosure
This site may link to third-party invoicing and accounts-payable software (e.g. FreshBooks, Melio, Bill.com). Where a link is a tracked affiliate link, this is disclosed on the relevant page per FTC guidelines. As of publication, links point to vendor homepages without tracking.