How to calculate a discount and final price

A 20% discount on a $200 list price leaves $160. If you then add 10% sales tax or VAT on that discounted amount, the percentage calculator returns $176 as the amount after tax. Those figures use Subtract percent and Add percent with the same library the tool runs in the browser. The percents are sample inputs for the math, not a claim about any current tax rate or promotion.

Formulas on their own lines

Discount amount (when you know the percent and the list price):

discount = (percent ÷ 100) × list

Sale price after one percent off:

sale = list × (1 − percent ÷ 100)

Tax or VAT added after the discount (sample percent on the sale price):

final = sale × (1 + taxPercent ÷ 100)

Stacked second discount on the already reduced price:

afterSecond = sale × (1 − secondPercent ÷ 100)

Worked checkout: discount, then tax

List price 200. Discount 20%. Tax 10% on the reduced amount.

1. Sale price with Subtract percent: 200 × (1 − 0.20) = 160
2. Tax with Add percent on 160: 160 × (1 + 0.10) = 176

Dollar discount alone with Percent of: 20% of 200 = 40. Then 200 − 40 = 160, same sale price. Tax dollars on the sale price: 10% of 160 = 16. Sale plus tax: 160 + 16 = 176.

20% of 200 = (20 ÷ 100) × 200 = 40

That line is the $40 discount slice. Switch the tool to Subtract percent with the same 20 and 200 to see 160, then Add percent with 10 and 160 to see 176.

Second case: stacked discounts (not “add the percents”)

A store takes 20% off, then an extra 10% off the sale price.

1. After 20%: 160
2. After extra 10% on 160: 160 × (1 − 0.10) = 144

A common mistake is to add the rates and take 30% off 200 in one step: 200 × (1 − 0.30) = 140. That is $4 cheaper than true stacking because the second 10% never sees the original 200. If a coupon says “extra 10% off the sale price,” use two Subtract percent steps. If it says “30% off list,” use one step.

Common mistake: tax dollars from the list price

People sometimes compute tax on the list price, then subtract the discount from that inflated total:

1. Tax on list: 10% of 200 = 20
2. Discount: 40
3. Wrong total: 200 − 40 + 20 = 180

The discount-then-tax path above paid 176. The gap is the tax that was charged on the discounted $40 slice (10% of 40 = 4). Receipts that tax only the taxable sale amount avoid that extra $4. Always read whether tax applies to the discounted base. This page does not state a jurisdiction’s rule.

How to run it in the tool

1. Open the percentage calculator.
2. For sale price: Subtract percent, percent = discount, base = list.
3. For tax after discount: Add percent, percent = tax sample, base = sale.
4. For a second coupon on the sale price: Subtract percent again with the new base.
5. For the dollar discount alone: Percent of.

Reset between scenarios so an old base does not linger. Nothing is sent to a server.

Reading a receipt without mixing stories

Keep three labels separate: list, discount, tax. If finance later asks “what percent did we save on list?”, use Is what percent with part = discount dollars and whole = list (40 is what percent of 200 → 20%). If they ask how the cart moved from list to final, percent change from 200 to 176 is a different question. For plain “X% of Y” drills, see how to calculate percentages. For add or subtract percent alone, see percentage change.

Promotional language can hide order. “20% off plus tax” usually means discount first. “Tax included” prices need a different unpack. When two coupons stack, write the intermediate sale price before the second percent so nobody silently sums the rates.

Round money to cents when you pay at a register. The calculator may show more decimal places in the formula line so chained examples stay exact. For these round inputs, 160, 176, 144, and 140 match the library with no leftover fraction.

Another quick check: smaller cart

List 80, discount 15%, then sample tax 8% on the sale price.

1. Subtract percent: 80 × (1 − 0.15) = 68
2. Add percent: 68 × (1 + 0.08) = 73.44

Dollar discount: 15% of 80 = 12. If someone taxes the list instead (8% of 80 = 6.4) and then subtracts the discount, they get 80 − 12 + 6.4 = 74.4, which is higher than 73.44 by the tax on the discounted slice. Same pattern as the $200 example, smaller numbers.

Write the chain on one line when you share it: “80 list → 15% off → 68 → +8% tax → 73.44.” That beats pasting a single final number with no path.