Discount calculations seem simple but produce surprisingly frequent mistakes — particularly when stores stack multiple discounts, quote discounts on inflated 'original' prices, or offer flat-amount discounts that look different from percentage discounts. This guide covers the three core discount calculations and how to think critically about Bangladeshi retail discounts.
The Three Core Discount Calculations
1. Sale price from discount percentage: Sale price = Original price × (1 − Discount % / 100) Example: ৳2,500 shirt, 30% off → ৳2,500 × 0.70 = ৳1,750 2. Discount percentage from prices: Discount % = [(Original price − Sale price) / Original price] × 100 Example: Original ৳3,200, sale price ৳2,400 → [(3,200 − 2,400) / 3,200] × 100 = 25% discount 3. Original price from sale price and discount: Original price = Sale price / (1 − Discount % / 100) Example: Paid ৳1,800 after 40% discount → ৳1,800 / 0.60 = ৳3,000 original price
Stacked Discounts — How They Really Work
When a retailer offers 20% off plus an additional 10% off, the result is not 30% off. The second discount applies to the already-discounted price, not the original.
Stacked discount calculation: Final price = Original × (1 − first discount) × (1 − second discount) Example: ৳5,000 item, 20% off then additional 10% off After first discount: ৳5,000 × 0.80 = ৳4,000 After second discount: ৳4,000 × 0.90 = ৳3,600 Total discount = ৳1,400 = 28% (not 30%) The effective combined discount is: 1 − (0.80 × 0.90) = 1 − 0.72 = 28%
Bangladesh Sale Seasons to Know
The largest retail discount events in Bangladesh follow a predictable calendar: Eid sales (before both Eid-ul-Fitr and Eid-ul-Adha, when ready-made garment retailers offer 20–50% off), New Year sales (both Bengali and Gregorian), and end-of-season sales for winter wear in January–February. E-commerce platforms (Shajgoj, Daraz, Chaldal) run additional promotional campaigns around their own sale events.
Tip
When shopping during a big sale, photograph or note the regular price of items you are interested in before the sale starts. Some retailers in Bangladesh mark prices up before marking them down — the '50% off' label means nothing if the 'original' price was inflated three weeks before the sale. Knowing the real pre-sale price is your best protection against fake discounts.