Apple Watch Ultra 4 and Garmin Fenix 9 Pro Show Comparable Precision in Independent Accuracy Test

The latest high‑end wearables from Apple and Garmin – the Apple Watch Ultra 4 and the Garmin Fenix 9 Pro – have both passed a recent accuracy trial, confirming that the premium price tags are matched by reliable sensor performance.

TechRadar’s evaluation focused on the devices' core health‑tracking capabilities, including heart‑rate measurement, altitude reading and GPS positioning. While Apple has promoted its newly overhauled Health Sensing System as the most precise on a wrist‑worn device, the Garmin model, long praised for its rugged design and multi‑satellite navigation, was put through the same series of real‑world scenarios.

Both watches recorded heart‑rate data that stayed within a narrow margin of error when compared to a medical‑grade chest strap, and their altitude readings aligned closely with a calibrated barometric reference. GPS traces from each device showed minimal deviation from a known route, underscoring the consistency of satellite lock even under dense foliage.

The findings matter for users who rely on wearables for training, safety or health monitoring. Accurate heart‑rate data informs calorie calculations and training zones, while reliable altitude and location metrics are crucial for hikers, climbers and first‑responders who depend on precise navigation in remote environments.

Industry analysts note that the convergence of performance between the two brands suggests a maturing market where competition drives incremental improvements rather than radical breakthroughs. Apple’s emphasis on sensor integration and Garmin’s focus on multi‑GNSS support each address different user priorities, yet both now meet the same benchmark for basic measurement fidelity.

Looking ahead, the test leaves open questions about long‑term battery endurance under continuous high‑precision tracking and how software updates might further refine data interpretation. For now, consumers can be confident that choosing either the Ultra 4 or the Fenix 9 Pro will not compromise on the fundamental accuracy of the metrics that matter most.