# insert(_:for:) Adds a new quantity to the series with the provided date interval. ``` func insert(_ quantity: HKQuantity, for dateInterval: DateInterval) throws ``` ## Parameters `quantity` The quantity to insert. `dateInterval` The date interval associated with the quantity. If the interval’s parameter is the same as the start date for a previously provided quantity, this quantity replaces the previous one. This method fails with an [`HKError.Code.errorInvalidArgument`](/documentation/HealthKit/HKError/Code/errorInvalidArgument) error if the date parameter is earlier than the series builder’s [`startDate`](/documentation/HealthKit/HKQuantitySeriesSampleBuilder/startDate) property. ## Discussion Use this method to add a quantity to the series. The quantity must have a unit that is compatible with the series builder’s quantity type (see [`is(compatibleWith:)`](/documentation/HealthKit/HKQuantityType/is(compatibleWith:))). > Note: > You can insert quantities in any order. The builder sorts them by the date interval’s property when you finish the series. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)