Máy tính điều khoản thanh toán hóa đơn

The Invoice Payment Terms Calculator analyzes early-payment discount offers (commonly notated 2/10 Net 30 — meaning '2% off if paid within 10 days, otherwise full amount due in 30 days') to compute the effective annualized return of taking vs declining the discount. The standard formula: Effective APR = (Discount% / (1 − Discount%)) × (365 / (Net Days − Discount Days)). For a 2/10 Net 30 invoice, that's (2/98) × (365/20) = 37.24% effective APR — extraordinarily attractive vs typical capital costs of 8–15%. Freelancers and B2B sellers use this in two directions. As an issuer offering terms: the discount cost (revenue forgone) is real but accelerated cash flow improves working capital and reduces collection risk. As a buyer evaluating an incoming discount offer: compare the 37% effective APR to your cost of capital (credit line rate, opportunity cost of cash sitting in operating account, or what you'd earn investing the money during the 20-day extension). If your capital cost is below the effective APR, taking the discount is positive expected value; if above (e.g., you're on a 50% APR credit card), declining is better. Common payment terms and their effective APRs: 2/10 Net 30 = 37.24% (strong incentive), 1/10 Net 30 = 18.43% (moderate), 2/10 Net 60 = 14.90% (weaker), 1/15 Net 45 = 12.29% (weak), 3/10 Net 30 = 56.44% (very strong, rare). The math heavily favors short discount windows + long net terms. Some industries use seasonal discounting (5% off in slow months) which calculates differently. The broader cash flow lesson: late-paying clients impose a hidden cost on freelancers. Net 60 vs Net 15 means working with 4× more outstanding receivables; at typical SMB credit line rates of 12% APR, every $10k of receivables held an extra 45 days costs $148 in interest. Aggressive payment terms (or factoring/invoice financing) preserve liquidity and reduce reliance on debt. This calculator gives the precise framework for making these tradeoffs quantitative rather than gut-feel.

PrimeCalcPro provides professional-grade tools trusted by businesses and academics.

1. 1Step 1 — Enter invoice amount
2. 2Step 2 — Enter payment terms (typically 'Net 30/60/90' meaning full payment due in N days)
3. 3Step 3 — Enter discount % and window (e.g., 2% if paid within 10 days)
4. 4Step 4 — Enter your cost of capital (line of credit rate, or what you'd earn with the money elsewhere)
5. 5Step 5 — Calculator computes discount dollar value: I × D%
6. 6Step 6 — Calculator computes effective APR: (D / (1−D)) × (365 / (ND − DD))
7. 7Step 7 — Compares effective APR to your cost of capital → take or decline recommendation

• !Comparing nominal discount % to APR directly (2% vs 12% APR feels close but 2/10 Net 30 is actually 37% APR)
• !Ignoring cash flow value of faster payment beyond the headline interest comparison
• !Forgetting that taking discount uses cash that could be invested elsewhere (opportunity cost)
• !Offering discounts to clients who pay reliably on time — pure revenue loss
• !Not charging late fees on overdue invoices — leaves money on the table