Shopping & Discounts
Save money by understanding discounts, sales tax, tips, and markup calculations. Smart shopping starts with percentage knowledge.
What You Will Learn
Smart shoppers think in final price, not discount percent. A 30% off $200 ($140) beats 50% off $100 ($50 saved vs $60 saved) only when you compare absolute savings and need.
True price = (Original − Discount) × (1 + TaxRate) + Fees. Stack coupons, cashback, and tax correctly — order matters when discounts compound.
Use the tools below before checkout, especially during Black Friday when inflated "original" prices are common.
Start With These Tools
Discount — Real Savings
See savings and final price for any percent-off deal.
Calculate Discount SavingsIn-Depth Articles
How to Calculate Discounts and Sales Tax (True Price)
Stop guessing at checkout. The true-price formula, why 20% + 10% is not 30% off, a $200 worked example, and how to spot fake Black Friday deals.
9 min read
Read ArticleCommon Questions
Is 20% off plus 10% off the same as 30% off?
No. Sequential discounts multiply: $100 → $80 → $72 (28% total), not $70. Retailers count on this confusion.
How do I spot a fake Black Friday deal?
Track price history, verify the "original" price over 30+ days, and compute unit prices. Our Black Friday hub shows verification steps.
Should I include tax when comparing deals?
Yes — always compare out-the-door totals including tax, shipping, and fees.
Last updated: · Reviewed by PercentLab Editorial Team
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