# Histogram A distribution of values organized into buckets. ``` struct Histogram where DimensionType : Dimension ``` ## Discussion Each [`Histogram.Bucket`](/documentation/MetricKit/Histogram/Bucket) in the [`buckets`](/documentation/MetricKit/Histogram/buckets) array covers a range from [`lowerBound`](/documentation/MetricKit/Histogram/Bucket/lowerBound) to [`upperBound`](/documentation/MetricKit/Histogram/Bucket/upperBound) and reports the number of samples in that range via [`count`](/documentation/MetricKit/Histogram/Bucket/count). You encounter `Histogram` as the type of properties on various metric structs, such as [`histogram`](/documentation/MetricKit/HangTimeMetric/histogram) and [`histogram`](/documentation/MetricKit/TimeToFirstDrawMetric/histogram): ```swift let histogram = metric.histogram // Histogram for bucket in histogram.buckets { let lower = bucket.lowerBound let upper = bucket.upperBound let count = bucket.count } ``` ## Topics ### Buckets [`let buckets: [Histogram.Bucket]`](/documentation/MetricKit/Histogram/buckets) ### Structures [`struct Bucket`](/documentation/MetricKit/Histogram/Bucket) ## Relationships ### Conforms To [`Decodable`](/documentation/Swift/Decodable) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`Encodable`](/documentation/Swift/Encodable) [`Sendable`](/documentation/Swift/Sendable) [`Equatable`](/documentation/Swift/Equatable) [`Hashable`](/documentation/Swift/Hashable) --- 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)