Deal Comparison Calculator
Compare discounts, coupons, shipping, tax and cashback to find the better deal.
Use the same currency for both offers. Dollar amounts accept up to two decimal places. Blank optional fields mean no charge, discount or cashback.
Your deal details and results stay in this browser tab and are not uploaded or automatically included in feedback.
Deal A
More discounts, coupon & cashback
Deal B
More discounts, coupon & cashback
Compare your offers
Enter an original price for both deals, including 0 for a free item, and resolve any input errors to compare.
Deal A
Enter an original unit price to see this deal.
Deal B
Enter an original unit price to see this deal.
Cashback is estimated money received later, not a discount at checkout. Check eligibility and payment terms before relying on it.
Calculation assumptions & privacy
Unit price × quantity gives the original merchandise subtotal. First discount, second discount and coupon apply in that order. Percentage reductions use the remaining merchandise; fixed reductions are per order. Discounts stop at zero.
Estimated tax applies only to discounted merchandise, excluding shipping. Checkout total is merchandise + tax + shipping. Cashback uses discounted merchandise for percentages; fixed cashback is per order. Cashback is an estimate received later, not an immediate checkout discount. Effective cost is checkout minus cashback, floored at zero.
Money rounds half-up to cents after each percentage adjustment, tax and cashback calculation. Per-unit effective cost also rounds to cents. Amounts accept up to $999,999,999,999.99 per field, quantity 1–100,000 and percentages 0–100 with up to six decimal places. Actual tax, coupon eligibility and cashback treatment vary by location and offer terms.
Inputs and results stay in this browser tab. They are not uploaded, saved or automatically included in feedback. Refreshing clears entries; copying uses your clipboard or the manual-copy fallback.
How it works
- Choose Compare Two Deals or Check One Deal. Enter original unit prices and quantities.
- Add a first discount, shipping and estimated tax. Open More discounts, coupon & cashback for optional adjustments.
- Results update immediately. Review checkout totals, later cashback and effective costs; expand the savings breakdown for each step.
- Use the same currency and compare equivalent products and quantities. Copy the summary if you want to keep it.
A real example
Fictional offers for the same item: Deal A starts at $100 with 20% off, then a $10 coupon, $5 shipping and 8% tax. Merchandise becomes $70, tax is $5.60 and checkout is $80.60. With 5% cashback on the $70 merchandise, estimated cashback is $3.50 and effective cost is $77.10.
Deal B costs $75 with free shipping and 8% tax, giving $81 at checkout. Deal A has a $3.90 lower effective cost, although its checkout advantage is only $0.40. Cashback must actually be received for the effective comparison to hold.
Stacked discounts are sequential
Two discounts of 20% and 10% do not equal 30% off. On $100, they reduce merchandise to $80, then $72: $28 saved. A percentage coupon also applies to what remains. Fixed discounts and coupons reduce the whole order once, rather than each item.
Merchandise savings measure the reduction from the original merchandise subtotal you enter. The difference between two offers compares their totals, including shipping, estimated tax and any entered cashback. Neither calculation verifies whether an original price is a genuine previous selling price.
Compare checkout and effective costs
Checkout is what this model estimates you pay now. Effective cost subtracts estimated cashback received later. With no cashback entered, the winner uses checkout totals; with cashback entered on either offer, it uses effective costs. Both checkout totals remain prominent.
Different quantities are flagged and no total-cost winner is declared. Use the rounded per-unit effective costs only when the products and units are comparable. A pack of six and a pack of twelve need quantities representing the same unit for a useful comparison.
Check the offer terms
Use this for everyday purchases, Black Friday or Cyber Monday offers without assuming that a promotion is a good price. Check discount stacking, exclusions, delivery fees and cashback eligibility with the store or provider. This calculator has no price history, retailer connection or best-price guarantee.
Tax defaults to discounted merchandise and excludes shipping; actual tax rules and coupon treatment vary by location. Percentage cashback also excludes tax and shipping. Adjust your entries to the offer terms where possible and confirm the final checkout amount before buying. Calculations use integer cents with half-up rounding at each monetary stage; there is no currency conversion.
Frequently asked questions
Can I calculate just one deal?
Yes. Select Check One Deal to see its checkout total, merchandise savings, estimated cashback and effective price per unit. Switch back to Compare Two Deals to compare a second offer.
How are stacked discounts and coupons applied?
First discount, second discount and coupon apply sequentially to the remaining merchandise subtotal. Percentage amounts round half-up to cents at each step. Fixed reductions apply once per order and cannot push merchandise below zero.
Is cashback deducted at checkout?
No. Checkout includes discounted merchandise, estimated tax and shipping. Cashback is shown separately and subtracted only for effective cost. Eligibility, caps, timing and payment depend on the offer; this tool does not verify them.
Which deal wins when quantities differ?
No total-cost winner is shown for different quantities. Compare effective per-unit costs for equivalent items, making sure that quantity represents the same unit on both offers. Per-unit values are rounded estimates.
What happens with a tie or a 100% discount?
Equal cent-rounded comparison totals are labeled tied. A 100% discount reduces remaining merchandise to zero, but shipping can still make checkout greater than zero. An original price of zero is valid; a blank price means not entered.
Does this prove an offer is a good Black Friday deal?
No. It compares the values you enter for any shopping occasion. It cannot verify original prices, historical lows, product equivalence or promotional claims, and does not create seasonal price-history tracking.
What currency and input limits can I use?
Use the same dollar currency for both offers; no conversion is performed. Amounts accept up to two decimal places, up to $999,999,999,999.99 per field. Quantity is a whole number from 1 to 100,000, and percentages range from 0 to 100 with up to six decimal places.
Are my deal details uploaded or saved?
No. Inputs and calculations remain in browser-tab memory. Refreshing clears them. Copying uses your clipboard or a manual-copy fallback; feedback does not automatically include deal labels, prices or results.
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