# Duration-based rentals

With the **Fixed durations** model, customers pick a rental length from a list, and each length is priced by its Shopify variant.

Video: [How to Create Dresses for Duration Based Rentals](https://www.youtube.com/watch?v=n8uQu8YzHeI)

## Set up durations on your products

1. In **Settings → Rental**, choose **Fixed durations** as the rental duration model.
2. On your Shopify products, add a variant option named exactly **Duration**, with values like **4 Days** and **8 Days**. Price each variant.
3. Import the products into Rental Products. To change prices later, use **Pricing** in [Edit Product](https://thedressrentalapp.com/docs/edit-product).

## Add durations in bulk

Already have lots of products without durations? Use **Settings → Data → Add Duration Options to Shopify Products**:

1. Set your **Rental Duration Fallbacks** (for example 4, 8, 12) in [Settings → Rental](https://thedressrentalapp.com/docs/rental).
2. Choose the **Shopify Product Type** to update.
3. Enter a **Price increase for each additional duration**. With 4, 8 and 12 days and 40%, the prices become base, base + 40%, and base + 80%, calculated separately for each size.
4. Click **Add missing duration options**. Only imported products with an exact type match are updated, in safe batches.

No Duration variant on a product? Customers can still choose from your fallback durations.

Source: https://thedressrentalapp.com/docs/duration