Percentage off or a fixed discount: which saves your child more?
By Erik Nilsen · Kroni3 min read
“20 per cent off” and “30 units off” look different, but you can compare them using the same calculation. Use one product and one starting price. This helps your child find what they would actually pay instead of choosing whichever advertised number looks larger.
Start with the original price
Imagine a pencil case your child wants. Its price before any discount is 120 units. Shop A offers 20 per cent off. Shop B reduces it by 30 units. These are invented offers using arbitrary money units for a teaching exercise.
One tenth of 120 is 12. Two tenths are 24. Offer A therefore takes off 24 units and leaves a final price of 120 − 24 = 96 units. Offer B leaves a final price of 120 − 30 = 90 units. The fixed discount saves your child another 6 units.
Write three lines for each offer: original price, discount in units, and final price. Leave delivery out of the first comparison, then add delivery to each final price if you actually intend to order online. A cheaper product with more expensive delivery may change the result.
Find the point where the offers match
With an older child, ask which starting price would make 20 per cent equal to 30 units. One fifth of 150 is 30, so the discounts match at 150 units. Below that price, a fixed reduction of 30 wins in this example. Above it, 20 per cent saves more. That only holds when the products and other terms are the same.
A realistic snag is discovering that the discounts apply to different pencil cases. One may have extra pockets or a different size. Pause the arithmetic and check what your child needs the case to do. Comparing different needs does not establish that one shop is cheaper.
Let your child check the final price before you order. A discount claim does not replace the amount in the basket. If a code does not work, use the price actually offered or decide against the purchase.
Ask your family: “If we remove the words percentage and special offer, which final price would you choose, and do both cases meet the same need?”
Carry the calculation into your family agreement
Kroni can keep track of your child's virtual balance. The app does not transfer money, so any actual purchase is paid for outside it. Agree on what you will record, then check the amount with your child afterwards. Do not deduct a possible cost as though the purchase had already happened. Read about allowance in Kroni.
