To sell window or privacy film by the roll on Shopify, give each roll width its own rate, let the shopper type a length, and add a percent-off ladder for bigger orders. With Appify Custom Product Options, the price follows the width and the length. The discount shows in the price summary before the shopper adds to cart.
The Privacy Film by the Roll demo on our Shopify demo store is built this way. This guide uses it to walk through the choices a film seller makes. If you want the single calculator taken apart, read inside a Shopify roll calculator.
What does a film seller need to decide?
Most of the work is choosing where each part of the price comes from. Here are the decisions, and how the demo answers each one.
| Decision | How the Privacy Film by the Roll demo answers it |
|---|---|
| How does the shopper pick a width? | Three buttons: 36", 48" and 60" |
| How does the shopper say how much? | A Length field with plus and minus buttons, starting at 1 |
| What does a wider roll cost? | Each width has its own rate: 21.59, 28.78 and 35.96 |
| What do bigger orders get? | Percent off, from 10% at 10 up to 30% at 50 |
| What does the shopper see before buying? | Subtotal, discount, total and price per unit |
| What does your team get? | The width and length on the cart line and the order |
Prices here are in dollars.
How do you price different roll widths?
Give each width its own button and its own rate. In the demo, 36" is 21.59, 48" is 28.78 and 60" is 35.96, and 36" is selected when the page loads. The shopper sees a price before touching anything.
Pick a wider roll and every unit of length costs more. A formula can read a pricing table, so your rate sheet can sit in one place and feed the field.
Global pricing tables are shared across your calculators. A rate change in the table reaches every film product that reads it.
Want the rate to have a name? A pricing variable such as ROLL_RATE is written once and reused in any formula or rule.
One product, no variant for every width and length. The width sets the rate, the shopper types the length, and the calculator does the multiplying. See what to use instead of variants for custom products for why the variant route runs out.
Should shoppers type a length or pick a roll count?
That depends on how you sell. Both are one setting on a Quantity option.
- A length they type. Choose the number field with plus and minus buttons. Set where it starts, the lowest and highest length, and the step. The demo starts at 1 and can't go below it, so nobody adds a roll with no length.
- A count they pick. Show quantities as buttons, a dropdown or a radio list, with a Custom choice if shoppers can enter their own. Turn on inline prices and each quantity shows its price, with a savings badge when a discount applies.
A fabric seller can run the same pattern with a yards-or-rolls choice. How to sell fabric, rugs and curtains by size covers fabric on the roll.
How do you build a volume discount ladder?
Add quantity discount rules in the simple mode, where the discount depends only on quantity. Each break has a minimum quantity, a discount type and a value. The demo uses percent off:
- 10 or more: 10% off
- 20 or more: 15% off
- 30 or more: 20% off
- 40 or more: 25% off
- 50 or more: 30% off
The highest break the order reaches is the one that applies. Discounts come off at checkout as line item discounts, so shoppers don't need a code.
Percent off is one of three types. A break can also take an amount off or set a target price per unit. If your ladder already lives in a spreadsheet, paste it with Import table instead of typing each break.
One roll product can also run a different ladder for each choice. Add a conditional table for a width, and the breaks follow the width the shopper picked. The guide to tiered and volume pricing for custom products covers the other ways to build a ladder.
What does the shopper see before they buy?
The price summary lets you choose which lines show. The demo shows four: Subtotal, Quantity Discount, Total and Price / unit. Once a discount applies, the old unit price is struck through and the new one sits beside it.
A shopper who buys a longer length can see what each unit now costs.
One order, worked out
Here is a 48" roll at a length of 12, with prices in dollars. Every number comes from the demo's price summary.
- Rate: 28.78 for each unit of length, so 12 units come to a subtotal of 345.36.
- Quantity Discount: 10%, the first break on the ladder.
- Total: 310.82.
- Price / unit: 28.78 struck through, then 25.90.
The discount takes 34.54 off the subtotal. Both the rate and the break show in one place, so the shopper can follow the price from 345.36 to 310.82.
What does the order carry?
The calculated price goes to checkout. Cart properties carry the width and the length, so the order says which roll was bought and how much. Your team sees the same lines in the app's Orders tab.
When a store turns on Edit options for a calculator, a shopper who picked the wrong width can change it in the cart and update the line. For a repeat order, Appify Reorder brings the width and length back, where Shopify's own Buy again drops them.
Build it with Chat with AI
Describe the film to Chat with AI and attach your rate sheet if you have one. A starting prompt:
"I sell window film by the roll. Add three width buttons: 36", 48" and 60". Add a Length field with plus and minus buttons that starts at 1. Price the length as the rate for the chosen width times the length, using the rates from my attached sheet. Add percent-off quantity breaks: 10% at 10, 15% at 20, 20% at 30, 25% at 40 and 30% at 50. Show the subtotal, the quantity discount, the total and the price per unit."
Before you publish, check four prices against your own sheet: the shortest length, a length one below a break, a length at the break and a length past it. The preview has a Price looks wrong? link that opens the Troubleshoot tab for those exact choices.
FAQ
How do I sell window film by the roll on Shopify?
Add the roll widths as buttons and a length as a Quantity option. The price follows the width and the length the shopper picks.
Can I sell film by the metre instead of by the roll?
Yes. Give the shopper a Length field to type into, as the demo does, and price it from your rate sheet.
How do I give a discount for longer orders?
Set percent-off breaks by quantity. The demo takes 10% off at 10 and rises to 30% off at 50.
Can each roll width have its own discounts?
Yes. Conditional discount tables run a different set of breaks for each choice.
Does the shopper see the discount before adding to cart?
Yes. The price summary shows the subtotal, the quantity discount, the total and the price per unit.
Every roll width, priced to the length.
Whatever you sell, however you price it · The last options app you'll shop for