Guides

38 practical reference guides on business days, payment terms, court filings, payroll, freight, and the day-counting rules that show up across professional work.

Payment Terms & Invoicing

What Is Net 15? Payment Terms Explained
What Net 15 means, calendar versus business days, how it compares with the statutory 30 days, and the FAR 15-day payment goal.
Updated: October 8, 2026
What Is Net 30? Payment Terms Explained
What Net 30 means and when the clock starts, calendar versus business days, the statutory 30 days, 1/10 and 2/10 discounts, and Net 30 EOM.
Updated: October 8, 2026
What Is Net 45? Payment Terms Explained
What Net 45 means, when the 45 days start, how it fits the 30-day and 60-day rules, and what the extra fifteen days cost the seller.
Updated: October 8, 2026
What Is Net 60? Payment Terms Explained
How Net 60 works and when the clock starts, the 60-day rules in EU, UK, German and Spanish law, and what two months of float cost the seller.
Updated: October 8, 2026
What Is Net 90? Payment Terms Explained
How Net 90 works, how EU, UK, German and Spanish law treat a term past 60 days, instalments as the alternative, and its cash-flow cost.
Updated: October 8, 2026
How to Write Payment Terms on an Invoice
The elements a payment term needs, the standard notation, where the terms go on an invoice, and the mistakes to avoid.
Updated: October 8, 2026
DSO Calculation: Days Sales Outstanding Explained
The DSO formula and its variants, what changes when you count calendar days or business days, and the common reporting traps.
Updated: October 8, 2026
How to Follow Up on an Unpaid Invoice
A reminder schedule you can use, with each message written out for days 1, 7, 14 and 30, and the UK and EU rules on when interest starts.
Updated: October 10, 2026
What to Do When a Client Won't Pay
The formal steps: the file, the letter before a claim in England and Wales, and the interest and fixed sum the UK Act adds, with a worked total.
Updated: October 10, 2026
Late Payment Interest Explained
The UK and EU statutory rates, Germany's § 288 BGB and Spain's Ley 3/2004, US federal contracts, and how to turn the rule into a number.
Updated: October 8, 2026
How to Charge Late Fees on Invoices
Disclosing the fee first, where it goes on the invoice, flat or percentage amounts, grace periods, and the statutory baselines.
Updated: October 8, 2026
The Dunning Process for Small Business
The four parts of a dunning process, what to record, the aging report, and the court procedures that follow in England and Wales, Germany and Spain.
Updated: October 10, 2026
2/10 Net 30 and Early Payment Discounts Explained
How to read the notation, why skipping a 2 percent discount works out to about 37 percent as a simple annual rate, three worked examples, and when to take or offer it.
Updated: October 8, 2026
End of Month (EOM) Payment Terms Explained
What EOM and its variants mean, how long an invoice waits under each, EOM with an early payment discount, and how it differs from Net 30.
Updated: October 11, 2026
How Payroll Cut-off Dates Work With Weekends and Holidays
The ACH banking day, paying early or late around a holiday, biweekly and semimonthly cutoff calendars, holiday clusters and state timing rules.
Updated: October 12, 2026

Calculations & Methods

Legal & Compliance

Tax & Finance

Operations

Reference & Tools

Tool comparisons

Alternatives and how-to comparisons

Comparisons with Excel NETWORKDAYS and Calculator Soup, a timeanddate.com page that is being re-checked, and when an online business day calculator suits a job better than a spreadsheet.

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