Which percentage calculations are most common in an online store?
In e-commerce, percentage calculations mostly answer five questions: the share of an amount, the ratio of one number to another, the change between two periods, price rises and discounts. The table below shows each with an example from a store.
| Question in the store | Formula | Example |
|---|---|---|
| If 8% of a ₺1,250 basket is the shipping share, how many ₺? | A × B ÷ 100 | 1.250 × 8 ÷ 100 = 100 ₺ |
| 54 orders from 3,600 visitors: conversion rate? | A ÷ B × 100 | 54 ÷ 3.600 × 100 = %1,5 |
| Average basket from ₺640 to ₺704: change? | (B − A) ÷ A × 100 | 64 ÷ 640 × 100 = 10% increase |
| If a ₺260 purchase price rises by 12%? | A × (1 + B ÷ 100) | 260 × 1,12 = 291,20 ₺ |
| If a ₺1,499 product gets a 30% discount? | A × (1 − B ÷ 100) | 1.499 × 0,70 = 1.049,30 ₺ |
What is the total discount when a campaign discount and a coupon are stacked?
Successive discounts are multiplied, not added; the total discount is always smaller than the sum of the two rates. Multiply the remaining rates and subtract from 1 to find the real discount.
Total discount = 1 − (1 − first discount) × (1 − second discount)
You can see what a discount takes off your profit in the discount calculator, and for campaign ideas see the e-commerce campaign examples article.
When interpreting the conversion rate, how do I tell percent from percentage points?
The difference between two rates is percentage points; dividing that difference by the old rate gives the relative percentage change. When the two are confused in store reports, a small improvement looks significant and a large drop looks small.
If the conversion rate went from 1.5% to 2.1%, the increase is 0.6 percentage points; in relative terms it is 0.6 ÷ 1.5 × 100 = 40%. Think of it as getting 140 orders instead of 100 with the same traffic. State clearly in your reports which one you are using. For ways to raise conversion, see the conversion rate optimisation article.
How should I pass a supplier price rise on to the selling price?
If you want to keep your profit margin rate, raise the selling price by the same rate as the purchase price; adding only the amount of the rise keeps the amount but lowers the margin rate.
If the purchase price is ₺260 and the selling price excluding VAT is ₺400, the margin is (400 − 260) ÷ 400 = 35%. After a 12% rise on the purchase price, the cost becomes ₺291. If you add only ₺31 to the selling price (₺431), the margin falls to 32.5%; if you also raise the selling price by 12% (₺448), the margin stays at 35%. Since prices are displayed including VAT, use the VAT calculator in the last step to find the label price.
How are average basket value and return rate calculated?
The average basket is found by dividing the period’s revenue by the number of orders; the return rate by dividing the number of returned orders by total orders and multiplying by 100. Both are among the most practical indicators for monitoring the health of your store every month.
Track separately which products have rising return rates; a missing size chart or product description often shows up in a single product.
Updated: · Calculations are for information only; consult your accountant for official transactions.