Kefiw

Archived noindex page. Kefiw's public focus is Property decision help.

Archived page

This older Kefiw page is kept for reference, marked noindex, and removed from the primary sitemap. The current Kefiw experience is focused on property decisions: cost, quotes, damage, buying, selling, owning, and packets.

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Discount Stacker

Layered discounts in order, with tax and cashback accounted for separately.

Real-world shopping rarely involves one discount. Stack a sale percent, a coupon (percent or dollar), an extra discount, a senior/loyalty percent, sales tax, and a cashback rebate — the calculator applies them in order and shows the effective discount, the amount due at checkout, and the net cost after cashback.

Start below
Fields marked optional can be skipped; results update as you type
You pay at checkout
$86.40
$86.40 + $0.00 tax
Net cost after cashback
$86.40
$0.00 cashback · 28.0% effective discount
Step-by-step
StepRateBefore− savedAfter
Original price$120.00
Sale20%$120.00$24.00$96.00
Coupon10%$96.00$9.60$86.40
Net cost$86.40
2 discount layers stacked → pay $86.40 at checkout, net $86.40 after cashback. Effective 28.0% off.
Original
$120.00
After discounts
$86.40
Net cost
$86.40
You save
$33.60
Effective %
28.0%
Your percent discounts add up to 30.0% on paper, but the effective discount is 28.0% — stacked percentages multiply the remaining price, so each subsequent discount takes a smaller cut.

How the stack works

Discounts apply in order. Each percent discount is taken on the price remaining after the previous step — this is why stacked percentages are always less than their sum. A dollar coupon is subtracted as a flat amount before the next percent discount. Tax is applied after all discounts. Cashback is a rebate on the post-tax total and does not reduce what you pay at the register.

How to use

  1. Enter the original price.
  2. Enter the sale percent.
  3. Pick coupon as percent or a flat dollar amount, then enter the value.
  4. Fill in any extra, senior, loyalty percents if they apply.
  5. Enter sales tax (applied after discounts).
  6. Enter cashback percent (applied to the post-tax total as a rebate).

Examples

$100 + 20% sale + $10 coupon + 5% senior + 7% tax + 2% cashback
Checkout: ~$70.04. Net after cashback: ~$68.64. Effective discount before tax: 31.4%.
Stacked percents are not additive
20% + 10% + 5% looks like 35% off but stacked equals 31.6% off — each percent applies to the already-reduced price.
Dollar coupon before percent
A $10 coupon after a 20% sale on a $100 item reduces the remaining $80 to $70 — not the original $100 to $70.

What users are actually trying to do

  • Sanity-checking a complicated checkout with multiple discounts
  • Comparing two stores’ offers when each has a different discount stack
  • Planning a coupon-heavy purchase to see the real savings
  • Understanding why stacked percents never match their sum

Common mistakes

  • ! Adding percents to get a fake total discount (they multiply, not add)
  • ! Counting cashback as if it lowers the checkout price
  • ! Applying tax before discounts (it is after)
  • ! Assuming every coupon stacks — many stores block combining promo codes

Before you trust the result

Check the inputs that matter most: dates, rates, units, costs, and any optional fields you skipped. A calculator can only work with the numbers entered here, so use the result as a decision check rather than a final answer when money, health, tax, legal, or safety consequences are involved.

If the result feels surprising, change one input at a time and watch which number moves. That usually shows the real lever behind the decision.

Limitations

  • · Applies discounts in a fixed order (sale → coupon → extra → senior)
  • · Does not model store-specific stacking exclusions
  • · Does not account for store credit card bonuses beyond the cashback field
  • · Does not handle per-item vs per-order discount scoping

Next up

Frequently asked questions

How do stacked discounts work? Definition

Stacked percent discounts apply in order and each percent is taken on the price remaining after the previous step. The effective total is always less than the sum of the individual percents.

Is a coupon applied before or after a sale discount? Edge case

Store policies vary. This calculator applies the sale first, then the coupon, because most checkout systems work that way — the coupon reduces the already-discounted price.

Does cashback lower the checkout price? Comparison

No. Cashback is a rebate earned after payment. You still pay the post-tax total at the register; the cashback amount is credited back later.

Why is the effective discount less than the sum? Definition

Because each percent discount applies to what is left after the previous one. 20% + 20% is not 40% — it is 36% off, because the second 20% is taken on the already-reduced 80% balance.

How do I calculate a senior discount? How-to

Enter the senior discount percent in its field. It applies after sale and coupon discounts in this calculator, matching most stacking rules.

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