Sell by Measure documentation

1. Set up a product

1. Open Sell by Measure in your Shopify admin.
2. Pick a product and choose Sell by measure.
3. Choose the unit (for example metres) and the step, the smallest amount you sell (for example 0.1 m).
4. Enter the price per unit (for example $12.00 per metre). The app sets the variant price to the price of one step ($1.20) and turns on Shopify's unit price, so shoppers see "$12.00 / m".
5. Optional: minimum and maximum amount, default amount, quick amounts (for example 1, 2.5, 5) and a label such as "Length".
6. Save. Products with several variants (colours, for example) get the same unit and step; each variant keeps its own price per unit.

If the price per unit cannot be split exactly into steps (for example $9.99 per metre sold per centimetre), the app shows the price per unit that shoppers will actually pay and asks you to confirm.

2. Add the block to your theme

1. In the app, click Open theme editor (it opens your product template with the block ready to add), or go to Online Store → Themes → Customize.
2. Open a product template, click Add block in the product information section and choose Measure input.
3. Save. The block replaces the theme's quantity selector on products sold by measure and does nothing on other products.

Block settings: label, price per unit on or off, quick amount buttons on or off, help text, accent colour and corner radius.

3. Turn on the checkout check

In the app, click Turn on checkout check (or go to Settings → Checkout → Checkout rules and add Sell by Measure: minimum and maximum amounts). Shopify then refuses amounts below a product's minimum or above its maximum, both when they are added to the cart or changed there and at checkout, with a message such as "Cotton fabric: the minimum is 0.5 m (you have 0.3 m)."

4. Stock

Stock is counted in steps. With a 10 cm step, 50 m of fabric is 500 in stock. The app shows stock in your unit next to each product. When stock is tracked and overselling is off, shoppers cannot ask for more than is left.

5. Orders, invoices and packing slips

Order lines show the product, the step as the variant ("10 cm"), the quantity in steps and the unit price, for example "Cotton fabric · 10 cm · $1.20 × 25 = $30.00 ($12.00 / m)". 25 × 10 cm = 2.5 m.

6. Plans

Plans are billed by Shopify. Change your plan from the app's Plan page.

7. Uninstalling

Uninstalling removes the block from your theme and turns off the checkout check. Variant prices and unit prices stay as they are (they are normal Shopify prices). To sell in whole items again, change the variant price back.

8. FAQ

Does it work on Basic Shopify? Yes. It uses no Shopify Plus features.

Can shoppers change the amount in the cart? Yes. The cart quantity is the number of steps, so any change is still an exact amount; the checkout check enforces the minimum and maximum.

Does it work with discounts, taxes and currencies? Yes. Shopify prices each step like any other item.

What about Shop app, POS and other channels? They see the step variant and its price. The measure input is only on your online store product page.