Far less usually remains from a single order than turnover or product margin suggests. A customer pays CZK 1,210, but a fifth of that is VAT, a large share is the cost of the goods, and the rest is gradually taken by the discount, the payment gateway, the carrier, the packaging and advertising. On a small order, the result easily reaches zero. Knowing the economics of a single order helps you set shipping, the free-shipping threshold and discounts more sensibly.
First convert the order to an amount excluding VAT
The customer sees a price including tax, but a VAT-registered store passes that tax to the state. At the Czech standard rate of 21%, an order of CZK 1,210 contains CZK 210 of VAT, leaving revenue of CZK 1,000. Czech VAT law also includes ancillary charges to the customer, such as transport and packaging, in the tax base, and a discount granted at the time of sale reduces it. So calculate shipping charges and discounts excluding VAT too.
A simple check where the calculation often goes wrong: Shoptet can show turnover and average order value with or without VAT, depending on a switch. An average order including VAT looks a fifth better than it really is, while purchase prices and most costs of a VAT-registered store are recorded excluding tax. If you are not VAT-registered, you cannot deduct input VAT, so count purchase prices and costs including VAT.
From gross margin to contribution per order
What we are aiming for is what management accounting calls the contribution margin: revenue minus the costs incurred with every additional sale. It first covers fixed costs – rent, wages, software – and only then becomes profit. For a single order, calculate it step by step, like a waterfall.
An illustrative card-paid order with free delivery to a pickup point (invented round values; fee and shipping based on public price lists):
| Line (excl. VAT) | Amount |
|---|---|
| Price of goods before discount | CZK 1,050 |
| Cost of goods | −CZK 630 |
| Gross margin | CZK 420 |
| Coupon discount | −CZK 50 |
| Payment fee (1.5% of CZK 1,210 + CZK 6.50) | −CZK 25 |
| Delivery to a pickup point | −CZK 72 |
| Box and filler | −CZK 15 |
| Advertising per order | −CZK 120 |
| Contribution per order | CZK 138 |
From a CZK 1,210 order, CZK 138 remains – just under 14% of revenue excluding VAT. Wages, warehousing, software and other fixed costs still have to come out of that.
Gross margin rests on purchase prices
Shoptet calculates profit margin only for products with a purchase price filled in. Before you start, check what share of revenue has a purchase price. A missing purchase price is not a zero cost; it is an unknown margin.
Payment: a percentage of the full amount, sometimes plus a fixed fee
Payment gateways usually charge a percentage of the payment, often with a fixed amount per transaction. Stripe’s public price list for Czech merchants, for example, showed 1.5% + CZK 6.50 for standard cards from the European Economic Area. The percentage applies to the full amount paid, including VAT and shipping. The rate also depends on the card type: EU regulation caps interchange fees only for consumer cards, which is why an older Comgate price list charged business and other unregulated cards roughly two to three times the rate for ordinary consumer cards. Fees for refunds and chargebacks belong to the cost of payment too. With cash on delivery, you pay the carrier a surcharge instead of a gateway fee – CZK 21 excluding VAT in Zásilkovna’s (Packeta’s) standard price list.
Shipping and packaging: a fixed amount on every order
Delivery costs the store a fixed amount regardless of order value. Zásilkovna’s standard price list valid from 1 June 2026 shows, for a standard parcel to a pickup point in the Czech Republic, CZK 62 when handed in at a depot and CZK 72 at a drop-off point, and CZK 89 and CZK 99 for home delivery, all excluding VAT and the fuel surcharge. Your contracted price may differ, but the order of magnitude shows why shipping matters most on cheaper orders. When the customer pays for shipping, subtract only the difference between what they paid (excluding VAT) and what delivery costs. Add the box, filler and any packing fee charged by an external warehouse.
Advertising: total spend divided by all orders
Calculate advertising per order as total monthly ad spend divided by the number of all orders in the same month. Ad platforms count only the conversions they credit to themselves, and the same order can appear in more than one of them, so a cost per order built from their figures does not match your actual order count. If you have the data, calculate it separately for new and returning customers.
A small order can end at zero
Fixed per-order costs – shipping, packaging, the fixed part of the payment fee and often advertising – are the same for a small purchase as for a large one. Illustratively: goods worth CZK 400 excluding VAT at a 40% margin, with the customer paying CZK 79 shipping including VAT.
| Line (excl. VAT) | Amount |
|---|---|
| Gross margin on CZK 400 of goods | CZK 160 |
| Shipping paid by the customer | +CZK 65 |
| Payment fee (1.5% of CZK 563 + CZK 6.50) | −CZK 15 |
| Delivery to a pickup point | −CZK 72 |
| Box and filler | −CZK 15 |
| Advertising per order | −CZK 120 |
| Contribution per order | CZK 3 |
Even with the shipping the customer paid, about three crowns remain. That does not make small orders a mistake – a small first purchase can bring a returning customer. It means you should know the order value below which you are paying to fulfil, and decide about it deliberately.
Orders, margin and costs together
Korzaro connects your store’s data so you can see orders, margin and costs for the same period in one place.
Free shipping: a threshold that has to pay for itself
Free shipping above a certain amount is a common way to raise order value. Research gives it a mixed verdict. A study of an online retailer that tested many shipping-fee schedules found customers highly sensitive to shipping charges, with free shipping and free-shipping thresholds lifting sales. Lost shipping revenue and the customer segments that did not respond, however, made the promotions unprofitable for the retailer. Another study showed that free-shipping promotions increase purchases of goods more likely to be returned, raising the return rate; for the firm studied, they increased net sales but were not profitable. A randomised experiment in an online shop also found that a free-shipping threshold leads to more strategic returns.
All three studies describe individual stores abroad, so they cannot tell you how your threshold will perform. They are a good reason to recalculate it. The method is simple:
- How much shipping revenue you give up. In the example above, CZK 65 excluding VAT on every order above the threshold.
- How much margin the extra goods must bring. At a 40% margin, the customer must add at least about CZK 163 of goods excluding VAT because of the threshold, or the threshold loses money on that order.
- Who would cross the threshold anyway. Customers who would have bought above it without the offer get free shipping without changing anything.
- How much comes back. When a customer withdraws from the contract, Czech law requires you to refund within 14 days the delivery cost up to the cheapest option you offered, while outbound delivery, packaging and the payment fee have already been paid.
If the threshold does not add up, you have several options: raise it, offer free shipping only on the cheaper delivery method, or test a minimum order value instead. In the experiment, a minimum order value did not reduce purchases and only slightly increased returns among existing customers, but your result may differ, so test it on part of your traffic or for a limited period.
What contribution per order leaves out
Contribution per order is useful precisely because it is narrow. It is not net profit and should not be called that. It usually leaves out:
- fixed and overhead costs – wages, warehouse rent, software, accounting;
- returns and complaints – unless you record them against specific orders;
- income tax and other taxes beyond VAT;
- costs you do not have in the data – such as manual packing time.
Do not fill a missing cost with an estimated percentage just to produce a “profit per order”. A precise-looking number built on a guess suggests certainty the data does not provide. It is better to label the result honestly – for example, “contribution after shipping, payment and advertising, excluding returns and overhead” – and add the missing item once you have it from a real source.
What to do now
- Pick two typical orders. One usual and one small, ideally from last month, and convert them to amounts excluding VAT.
- Check purchase prices. Find out what share of revenue has a purchase price recorded; without it, gross margin is unreliable.
- Fill in real rates. Payment fees from your gateway contract, shipping from the carrier’s invoice, packaging from your purchases and advertising as total monthly spend divided by all orders.
- Find the break point. Work out the order value below which nothing remains after shipping, payment and advertising.
- Recalculate your free-shipping threshold. Compare the shipping revenue you give up with the margin the extra goods bring, and watch whether returns rise above the threshold.
- Label the result. For every number, state which costs it includes and which it does not.