Shopify blinds configurator: made-to-measure width, height, and extra choices

A Shopify blinds configurator is not a Size dropdown. The shopper measures the recess (46.5 in wide, 56 in high), picks slat colour, control side, and mount — and expects that combination priced on the product page. Native Shopify gives you three variant options and at most 2048 combinations. Free centimetres for width *and* height, plus three more choices, do not fit.

This article is for window-covering shops, interior specialists, and stores that cut Venetian, wood, or aluminium blinds to order. You will see why five buyer choices exhaust the three-option ceiling, how measurements and surcharges live in one formula, and how Options Price Calculator puts that flow on the product page without a SKU per millimetre.

Continuous sizes instead of S/M/L are in Shopify custom size pricing. This piece is one vertical: blinds, including slats, controls, and mount — more fields than custom curtains or window film.

Why blinds spend Shopify’s three options immediately

Shopify Help Adding variants is the source of truth:

• each product may have up to three options (for example Size, Color, Material);

• each product may contain up to 2048 variants.

The variant cap moved from 100 to 2048 in October 2025 (Shopify changelog). That helps a t-shirt with many sizes × colours. It does nothing for blinds. A realistic order usually needs at least:

1. Width (continuous cm or mm)

2. Height (continuous)

3. Slat colour or fabric (often 8–20 swatches)

4. Control side (left / right, cord or chain)

5. Mount (inside recess / outside, or face fix)

Items 3–5 already fill the three option slots. Items 1–2 are not dropdown values: 40 to 300 cm in 1 cm steps is 261 widths *before* height. Even without millimetres, the combinatorics blow up. Twelve colours × two control sides × two mounts = 48 variants — and you have no slot left for size. Add those 261 widths and you are far past 2048, still without height.

In How can I add a custom sizing feature for blinds and curtains? a merchant wants the shopper to type width × drop and get a price — sometimes from breakpoint bands, not a simple m² rate. I'm looking an app asks for the same product-page flow as a made-to-measure blinds site: enter sizes, pick options, see price. The three-option ceiling itself is the subject of Adding more than 3 options in Shopify admin. A blinds configurator sits on that overlap: too many choices *and* continuous measurements.

Workarounds shops try first

Kit sizes as variants

“60 × 120”, “80 × 140”, “100 × 160” as Size. Fast in admin, useless for a 93 × 147 cm recess. Shoppers who fall between kits email you or order too small — then return.

Split the catalogue by style

Aluminium, wood, and pleated each get their own product so every page has three options again. That stays inside the limit, but you duplicate content, muddy related products, and send customers hopping URLs for control side.

Line item properties or a quote

`<input name="properties[Width]">` stores the measurement on the line item. The price does not change. A 40 × 60 cm bathroom window and a 240 × 220 cm bay cost the same until you add a calculator or a Shopify Function. WhatsApp quotes work for a local fitter; they kill Shop Pay and abandoned checkout.

Measurements belong beside variants, not inside them

Keep native variants for what you actually stock: a slat collection with its own purchase SKU and lifestyle photo, or aluminium versus wood. Anything that does not need an inventory row — free size, control side, mount, cordless surcharge — belongs in product options with a formula.

Options Price Calculator is built for that split: unlimited fields on the product page, a live total, no extra variant per millimetre. It is Built for Shopify (listing: 5.0 from 25 reviews). Conditional logic, live preview, and price breakdown are Premium; AI-assisted fields and formulas sit on Starter and above. For the three-option ceiling itself, see Shopify more than 3 product options.

Typical fields for one blinds calculator:

| Field | Type | Role in the price | |------|------|-------------------| | Width (cm) | Number Input, key `width` | required, min/max | | Height (cm) | Number Input, key `height` | same | | Slat colour | Swatch or dropdown, key `slat` | `0` or a collection surcharge | | Control | Radio, key `control` | `0` or a surcharge (chain vs. cord) | | Mount | Dropdown, key `mount` | often `0`; a value for extra brackets | | Cordless | Checkbox, key `cordless` | `0` or a flat fee |

Be deliberate about units: either convert to metres (`width / 100`) or price in currency per cm². The formula builder supports `+ - × ÷ ( )` and helpers such as `Math.ceil`. Leave *Is quantity input* off — that binds the number to Shopify cart quantity, not to a recess. The docs tip is explicit: always set a minimum and maximum on number fields so a 12-metre bay cannot slip through checkout.

Simple, when `product_price` is the m² rate of the selected variant (wood vs. aluminium as a real SKU):

``` product_price * (width / 100) * (height / 100) ```

One product, slat collection as a dropdown multiplier, plus a €25 setup fee as in the formula examples:

``` product_price + 25 + ((width / 100) * (height / 100) * slat) + cordless ```

`product_price` can be 0 if the whole total comes from the formula, or a fixed cutting charge. A mount dropdown with value `0` or `18` adds on. Unchecked checkboxes contribute `0`.

Premium conditional pricing is for thresholds, not the base formula. Examples from the docs: a higher rate when `width > 200` (two drops, extra handling), or a floor so a 40 × 40 cm WC window does not fall below cutting cost. A live preview of slats on a window photo is Premium as well. Label the plan that way.

The calculated price is validated server-side; it is not a browser-only display trick. Width, height, colour, and control travel on the line item so the workshop sees the same centimetres as checkout.

A recess of 118 × 142 cm

Wood Venetian, m² rate €62 (as `product_price` on the wood variant), recess 118 × 142 cm, cordless surcharge €35, no extra brackets.

• Area: 1.18 × 1.42 = 1.6756 m²

• Slats: 1.6756 × 62 ≈ €104

• Plus cordless €35

In the formula:

``` product_price * (width / 100) * (height / 100) + cordless ```

That is one product, one calculator, zero extra variants for size. “Aluminium 25 mm” versus “wood 50 mm” can still be a native variant if you want a purchase SKU per slat type — link the calculator per variant. More than three choices (colour + control + mount + cordless) sit beside those SKUs, not inside them.

Get it on the product page

1. Install Options Price Calculator. Free plan: 20 uses, always free on a Shopify Develop store. Starter ($9.99/mo) for unlimited options, the formula builder, and AI. Premium ($14.99/mo) for conditional logic, font picker, live preview, and price breakdown.

2. Add the app block on your product template, ideally below the price and above Add to cart — How to Add the Extension to the Product Page.

3. Create the fields above. Number inputs: label `Width (cm)` / `Height (cm)`, default a common recess, min/max matching production (for example 30–300 cm). Required on, *Is quantity input* off, negatives off.

4. Set the formula, test with preview values (118 × 142, both materials, cordless on/off). Round only at the end with `Math.round` or `Math.ceil` if you want whole currency units.

5. Link the calculator to the blinds variants. A whole collection at once: bulk linking.

Wrap-up

Blinds are not a Size dropdown. They are recess × rate, with slat, control, and mount beside it — more choices than Shopify allows natively, plus two continuous measurements. Put that configurator on the product page and keep the catalogue on the slats you actually stock.

Install Options Price Calculator and let customers type the recess instead of guessing between kit sizes.