Discount Calculator

How the Calculations Work

Mental shortcuts for common discounts

India shopping context

During major sales like Flipkart Big Billion Days, Amazon Great Indian Festival, and Myntra End of Reason Sale, discounts of 40–80% are common. Always verify the MRP shown is the genuine pre-sale price (check if the MRP was inflated before the sale). Also note that GST applies to the final sale price, not the MRP — so a product sold at ₹800 after 20% off from MRP ₹1,000 has GST calculated on ₹800.

Percentage off vs percentage points

A surprising amount of confusion — and a fair bit of misleading advertising — comes from mixing up "percent" and "percentage points." If a jacket was 20% off last week and is 30% off today, the discount grew by 10 percentage points, but it grew by 50 percent (because 30 is 50% more than 20). Both statements are true; they just measure different things. The discount you actually pay is always the percentage of the price, so when you compare offers, convert everything to the final rupee amount rather than arguing about points. A "10 percentage point" jump from 20% to 30% off a ₹2,000 item moves the price from ₹1,600 to ₹1,400 — a real ₹200 — which is the number that matters at the till.

Markup vs margin: why a 50% markup is only a 33% margin

Shoppers think in discounts; sellers think in markup and margin, and the two are easy to confuse because both are percentages of a price difference — just measured against different bases. Markup is the profit expressed as a percentage of cost; margin is the same profit as a percentage of the selling price. A product that costs a shop ₹100 and sells for ₹150 carries a 50% markup (₹50 on a ₹100 cost) but only a 33.3% margin (₹50 on a ₹150 price). They are never equal, and the gap widens as numbers grow:

This matters when a retailer offers a discount: a shop running on a 33% margin literally cannot give "40% off" and still profit, which is a useful sanity check on whether a "60% off MRP" claim reflects a genuine reduction or an inflated starting price.

Discount plus tax — does the order matter?

A common worry at checkout is whether applying the discount before or after tax changes what you pay. For a straightforward percentage discount and a percentage tax, it does not — multiplication is commutative, so discount-then-tax and tax-then-discount give the same total. Take a ₹1,000 item, 20% off, 18% GST: discount first gives ₹800, then ×1.18 = ₹944; tax first gives ₹1,180, then ×0.80 = ₹944. Identical. In Indian practice GST is charged on the transaction value — the discounted price you actually pay — so the sequence that happens on your bill is "discount, then tax," and the maths above confirms that's the same total either way. Where order genuinely can matter is with a flat-rupee coupon (₹200 off) combined with a percentage tax, or with multiple stacked offers — there, work through the bill step by step rather than assuming.

Why two discounts never simply add

"20% off, plus an extra 10% at checkout" sounds like 30% off, but it is not — the second discount applies to the already-reduced price, so the discounts compound instead of adding. The correct way to combine them is to multiply what's left after each: a 20% and a 10% discount leave 0.80 × 0.90 = 0.72 of the price, which is a 28% total reduction, not 30%. The general formula for two stacked discounts is:

Effective discount = 1 − (1 − a) × (1 − b)

where a and b are the two rates as decimals. Stacking a few moderate offers therefore always undershoots their sum — three "20% off" coupons stacked give 1 − 0.8³ = 48.8%, not 60%. The one exception is a flat amount taken off the top (a ₹500 voucher) followed by a percentage, which doesn't follow this rule; for those, the modes above let you work the bill in stages.

Reading a sale honestly: anchoring and reference prices

The reason "₹4,999, now ₹1,999" feels so compelling is a well-documented cognitive bias called anchoring: the first number you see frames your judgement of everything after it, so a high "original" price makes the sale price feel like a steal even if few people ever paid the anchor. Retailers know this, which is why a struck-through reference price sits next to almost every sale tag. The honest question to ask is whether that reference is a real, recently-charged price or an inflated list price that exists mainly to make the discount look large.

India has a specific guardrail here: the MRP (Maximum Retail Price) printed on packaged goods is a legal ceiling — the most a seller may charge, inclusive of all taxes — not necessarily the market price. Many products routinely sell below MRP even without a "sale," so a discount measured against MRP can overstate the real saving. The reliable move is to compare the final price against what the item actually costs elsewhere today, not against the anchor the seller chose. This calculator's "Find % off" mode is handy for exactly that: feed in a competitor's price as the original to see the true discount you're being offered.

Discounts, coupons, rebates and cashback

"Getting money off" comes in several mechanics that feel similar but differ in timing and certainty:

Because cashback and rebates pay out after the sale — and sometimes never, if you forget to claim — a smaller upfront discount can be worth more than a larger deferred one. To compare like with like, convert every offer to the actual rupees you keep, which is what all three modes of this calculator are built to do.