# recalibrateEstimates(sampleType:date:completion:) Recalibrates the prediction algorithm used to calculate the specified sample type. ``` func recalibrateEstimates(sampleType: HKSampleType, date: Date, completion: @escaping @Sendable (Bool, (any Error)?) -> Void) ``` ``` func recalibrateEstimates(sampleType: HKSampleType, date: Date) async throws ``` ## Parameters `sampleType` The sample type to recalibrate. `date` The effective date for the recalibration. `completion` A completion block that the system calls after recalibrating the data used by the prediction algorithm. The system passes the following parameters: - `success`: A Boolean value that indicates whether the system successfully recalibrated the sample type’s estimates. - `error`: If `success` is , this parameter contains error information; otherwise, it’s `nil`. ## Discussion Your app can use this method to recalibrate HealthKitʼs prediction algorithms after an event that may significantly affect their results. For example, you can recalibrate the [`sixMinuteWalkTestDistance`](/documentation/HealthKit/HKQuantityTypeIdentifier/sixMinuteWalkTestDistance) type to use only data collected after a mobility-impacting health event, such as surgery or an injury. Recalibrating [`sixMinuteWalkTestDistance`](/documentation/HealthKit/HKQuantityTypeIdentifier/sixMinuteWalkTestDistance) after such an event may yield more accurate estimates during the recovery period. > Warning: > Before calling this method, your app must include the `com.apple.developer.healthkit.recalibrate-estimates` entitlement. Also, you must request both share and read access to all the data types you pass to the `sampleType` parameter. If you haven’t completed all of these steps, recalibration fails with an ``doc://com.apple.healthkit/documentation/HealthKit/HKError/Code/errorAuthorizationDenied`` error. Check the [`HKSampleType`](/documentation/HealthKit/HKSampleType) class’s [`allowsRecalibrationForEstimates`](/documentation/HealthKit/HKSampleType/allowsRecalibrationForEstimates) method to see if a given sample type supports recalibrating the algorithm. The following sample code recalibrates the estimates for the six-minute walk test. ```swift // Access the HealthKit Store. let healthStore = HKHealthStore() // Get the six-minute walk test type. let sixMinuteWalkType = HKQuantityType(.sixMinuteWalkTestDistance) // Verify that the type supports resetting estimates. if sixMinuteWalkType.allowsRecalibrationForEstimates { // Reset the estimate. healthStore.recalibrateEstimates(sampleType: sixMinuteWalkType, date: Date()) { (success, error) in // Check the success value. if !success { if let error = error { // Handle errors here. } } } } ``` --- 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)