Invoice Payment Term Extractor (Net 30/60/90)

A payment-terms string is a compressed contract carrying at most three numbers and one clock rule, and the whole extraction problem is recovering them. In d/D net N notation, d is the percentage deducted for early settlement, D is the last day that deduction is allowed, and N is the day the gross amount falls due; a bare net N carries no discount, while EOM or the older proximo marker moves the origin of both counts from the invoice date to the last calendar day of the invoice month. Once those numbers are recovered the dates are simple addition, but the interesting quantity is the price of the delay. Paying on day D costs the invoice amount times (1 - d); paying on day N costs the full amount. The buyer has therefore borrowed amount x (1 - d) for (N - D) days and repaid amount, so the interest is amount x d and the periodic rate is d / (1 - d). Annualizing with 365 / (N - D) periods gives the standard cost of trade credit, [d / (1 - d)] x [365 / (N - D)], and compounding the same periodic rate gives the effective annual rate. Using d instead of d / (1 - d) in the numerator is the most common error and understates the cost, because the discounted amount, not the gross amount, is what was actually financed. The magnitudes are the reason the calculation matters. Terms of 2/10 net 30 price 20 days of credit at 37.24 percent nominal and 44.59 percent effective; 1/10 net 30 works out at 18.43 percent nominal; 3/10 net 30 reaches 56.44 percent nominal and 74.35 percent effective; stretching the same 2 percent discount over 2/10 net 60 falls to 14.90 percent because the borrowed window is 50 days rather than 20. The nominal figure has a precise decision meaning: it is exactly the simple-interest borrowing APR at which paying early and paying late cost the same, so any short-term facility priced below it justifies borrowing to take the discount. Several conventions can shift the headline number without changing that ranking. A 360-day banker's year turns 37.24 percent into 36.73 percent. Discounts are usually computed on the goods value only, excluding freight and sales tax or VAT, so the cash saving is smaller than d times the invoice grand total. The day count may run from the invoice date, from receipt of goods, or from receipt of an undisputed invoice, and a disputed line can restart it. Finally, settlement is not instantaneous: weekends, public holidays and one to three days of ACH or BACS clearing all sit inside the discount window, so the practical deadline is earlier than the printed one.

Cash discounts for prompt settlement are older than the notation used to write them. Mercantile houses trading on open account needed a way to price the gap between delivery and payment, and terms expressed in months of the following period gave English commercial correspondence its proximo, ultimo and instant vocabulary, of which the surviving prox. and EOM markers are direct descendants. The compact d/D net N form became the American standard for stating those offers on the face of an invoice, and the underlying bargain was codified rather than invented by statute: Article 2 of the Uniform Commercial Code, published in official text in 1952 and first enacted by Pennsylvania in 1953, supplied default rules for terms of sale that let parties rely on short notations without restating them at length. The annualized cost formula entered general use through corporate finance teaching, where [d / (1 - d)] x [365 / (N - D)] is presented as the nominal cost of trade credit and paired with its compounded effective-rate counterpart. Late payment eventually drew legislators in, which is why net terms now sit against a statutory backstop in much of the world. The United States Prompt Payment Act, Public Law 97-177 of 1982 and substantially strengthened by the amendments in Public Law 100-496 of 1988, requires federal agencies to pay contractors on time and to pay interest automatically when they do not; the implementing rules sit in 5 CFR Part 1315. The United Kingdom created a statutory right to interest with the Late Payment of Commercial Debts (Interest) Act 1998, set at the Bank of England base rate plus 8 percentage points. The European Union followed Directive 2000/35/EC with the recast Directive 2011/7/EU in 2011, which fixes a 30-day default payment period for public authorities, caps business-to-business terms at 60 days unless a longer period is expressly agreed and is not grossly unfair, sets statutory interest at the European Central Bank reference rate plus at least 8 percentage points, and adds a minimum fixed recovery compensation of 40 euro per late invoice. More recently, supply-chain finance and dynamic discounting platforms have replaced the single fixed discount date with a sliding scale in which the deduction shrinks continuously as the payment date approaches the net due date, which is the same d / (1 - d) arithmetic evaluated at every intermediate day rather than at one.