Discount Calculator
See your final price and exact savings in seconds. Supports percentage discounts, fixed amount off, sales tax, and 10 currencies.
- Auto-apply rules remove the need for coupon codes, so customers never leave your checkout to find a discount elsewhere.
- Set discounts based on cart value, product, category, or customer for more targeted offers than a blanket coupon code.
- Schedule discounts to start and expire automatically so you never forget to turn off a promotion after it ends.
- BOGO and spend-and-save rules increase average order value while still giving customers the feeling of a great deal.
- Cart progress bars show shoppers how close they are to unlocking a discount, motivating them to add more to their cart.
- Discount usage limits and per-customer caps let you stay in full control of your margins without any manual monitoring.
How to Calculate a Discount or Percent Off
There are two numbers that matter: the original price and the discount rate. Everything else follows from those.
This calculator handles all four of these automatically. It also includes a sales tax field select “No” on the tax toggle to add your local sales tax rate and see the final price including tax.
Discount Formula
The core discount formula used by this sale calculator is:
For a fixed amount discount the formula is simpler: Final Price = Original Price − Discount Amount.
Stacked discounts where a second percentage is applied to an already-discounted price use the same formula twice, not once. A 20% discount followed by a 10% discount on a $100 item gives $100 × 0.80 = $80, then $80 × 0.90 = $72. The effective rate is 28%, not 30%.
Types of Discounts
Percentage discount. The most common type. A set percentage is deducted from the original price a 20% discount on a $50 item is $10 off. Most retail promotions, coupon codes, and sale events use this format.
Fixed amount discount. A flat dollar amount deducted regardless of total. “$15 off orders over $75” is a fixed discount. The maths is simpler but the effect on margin varies $15 off a $20 item is very different from $15 off a $500 item.
BOGO (Buy One Get One). Effectively a 50% discount when buying two units. The saving is real, but only if you’d have bought the second item anyway.
Tiered/quantity discounts. Larger discounts at higher purchase volumes common in wholesale and B2B. Calculate each tier separately and compare total cost to find where your order sits.
Stacked discounts. Two discounts applied sequentially. A 20% discount followed by 10% off is 28% effective not 30%. Each discount applies to the already-reduced price, so the result is always lower than the sum of the two rates.
Worked Examples
How WooCommerce Store Owners Can Automate Discounts
Calculating discounts manually works for one-off situations. Running promotions at scale is a different problem.
The typical pain points: customers leave checkout to hunt for a coupon code that may not even exist, promotions run past their end date because someone forgot to turn them off, and BOGO rules require manual order adjustments.
Power Coupons handles this at the rule level rather than the code level. You define the condition cart value over $50, specific product, repeat customer and the discount applies automatically at checkout. No coupon code needed, no manual expiry checks, no leakage to third-party coupon sites.