A website is a machine for charging a fixed price for a fixed thing. A butternut squash has never agreed to this. Neither has a leg of lamb, a whole cheese, or a bunch of carrots pulled out of the ground five minutes ago.
Every shop selling food by weight hits the same wall: the price on the page and the weight in the bag are not going to match, and somebody has to deal with the difference.
Sell a unit, not a weight
The cleanest answer, and the one most farm shops land on eventually, is to stop selling weight and start selling a defined unit.
Instead of carrots at a price per kilo, sell "carrots, approximately 1kg bunch". Instead of lamb mince by weight, sell "500g pack". The customer buys a thing with a price. You pack to a target and the arithmetic disappears.
This works because it matches how people actually shop for food. Almost nobody wants 850 grams of carrots. They want carrots for the week.
- Pick round, useful sizes. 500g, 1kg, a half dozen, a dozen. Sizes that map to a meal or a week.
- Say "approximately" and mean it. A stated tolerance, roughly plus or minus ten per cent, is normal in food retail and nobody objects to it when it is on the label.
- Price the unit, show the equivalent. "1kg bag, £3.20 (£3.20/kg)" gives the shopper the comparison they want without making the checkout do variable maths.
Where a true variable weight is unavoidable, sell it as an order
Some things genuinely cannot be packed to a target. A whole turkey at Christmas. A side of beef. A large squash that is whatever size it grew to.
For those, stop trying to make the checkout price it exactly. Two workable shapes:
- Sell a deposit against the item, with the balance settled at collection. The website takes the commitment, the scales settle the number. Say this plainly on the product page so nobody is surprised at the counter.
- Band the sizes. Small (3-4kg), medium (4-5kg), large (5-6kg), each a separate option at its own price. It is less precise than scales and it is far less work than reconciling forty individual weights, and for poultry it is what customers already expect.
The one thing not to do is take full payment for an exact weight and then hope. Refunding twenty pence to eleven people is worse than any pricing scheme.
Put the weight on the product so postage works
Separately from what you charge, the shop needs to know what things weigh, because postage brackets are calculated from it. A box of jam and a box of flour cost different amounts to send and a flat rate quietly loses money on one of them.
Fill in the weight field on anything you post. It costs a minute per product and it is the difference between shipping that pays for itself and shipping you subsidise. Zones and weight brackets are in shop settings, and the broader choice is in Shipping Options for a Small Online Shop.
For collection-only items the weight matters less, but fill it in anyway. The day you add a delivery round, it is already there.
Be careful with price-per-unit rules
In the UK and across the EU, unit pricing on food is not purely a courtesy. Selling by weight generally means showing a price per kilogram or per litre alongside the selling price, so shoppers can compare. The rules differ by country and by product, and there are exemptions for small quantities and for some loose goods.
Showing it is the safe default and it is also good practice. A shopper comparing your 1kg bag against a supermarket price wants that number, and if you do not give it they will assume the worst.
If you sell across borders, check the local rule rather than assuming your own applies. That is a conversation for whoever does your books, not a decision to make from a blog post.
Say what the weight actually gets them
The number is the least interesting thing about the product. "1kg bag" is a fact. "1kg bag, about eight decent-sized carrots, enough for a roast and a soup" is a reason to buy.
For anything unfamiliar, add the translation. How many people does this joint feed. How many portions in this squash. Whether the bunch includes the tops. Small shops consistently underrate how much of their in-person value is answering that question at the counter, and how easy it is to write down once.
The rule of thumb
If you can pack it to a target, sell a unit. If you cannot, band it or take a deposit. Either way, record the real weight for postage, show the price per kilo, and describe what the unit actually feeds.
The farm shop website builder page shows the shop, the stock side is in Selling Stock That Changes Every Week, and you can start for free with whatever came out of the ground this morning.