PacerX vs RunBests

How fast could you race today? PacerX turns the runs already in Apple Health into personalized 5K, 10K, half marathon, and marathon predictions—then shows you the training evidence behind every estimate. Built for runners who want more than a workout list or a one-result pace calculator, PacerX looks across your recent training, best efforts, trends, pace, heart rate, effort, weather, elevation, and consistency to help you understand where your fitness is heading. SMARTER RACE PREDICTIONS See realistic estimates for 5K, 10K, Half Marathon, and Marathon based on your recent training. Open any prediction to understand the runs and signals that influenced it. PREDICTION HISTORY Track how your projected race fitness changes over time. See when your training is moving the needle—and when your estimates are holding steady. DEEP ANALYSIS On supported devices, Deep Analysis uses Apple Intelligence to give you a deeper explanation of what your recent training says about race readiness. PacerX uses on-device processing where appropriate and can use Apple Private Cloud Compute for supported Deep Analysis requests. COMPARE YOUR RUNS Open any run and compare it with a relevant past workout—or choose one yourself. Review pace and heart-rate charts, side-by-side metrics, and context such as route, distance, effort, weather, and elevation. FIND YOUR BEST RUNS Discover validated personal bests and standout efforts across your running history, including 1K, mile, 5K, 10K, half marathon, marathon, longest run, most climbing, most consistent splits, and more. SEE THE FULL PICTURE Review weekly mileage, monthly and yearly trends, pace, heart rate, cadence, elevation, perceived effort, shoes, running surface, weather, and other context from your training history. PRIVATE BY DESIGN PacerX reads your running data from Apple Health. No account is required, there are no ads, and your running history isn't used to build advertising profiles. Optional Deep Analysis may securely process derived training insights using Apple Private Cloud Compute, where request data is not stored. PacerX doesn't replace your coach or training plan. It gives you a clearer picture of what your training says—so your next conversation, workout, or race decision starts with better context. Understand your training. See what you're ready for. Keep moving forward.

Run Bests finds your personal best running times in Apple Health. Runs rarely end at exactly the same distance. Set the distances you care about and choose a margin to group comparable workouts. A 5-mile target with a 0.25-mile margin includes runs from 5.0 through 5.25 miles. COMPARE TIMES CLEARLY Workout time covers the full run and uses the duration reported by Health. Race time estimates how long it took to reach your target distance from the start. Both exclude pauses. Each has its own pace, and the workout detail explains which time you are viewing. FIND YOUR FASTEST SEGMENTS See your fastest continuous 1 mile, 1 km, or custom distance anywhere within a run. Segment estimates use Health's recorded distance samples when available, with GPS as a labeled fallback. A best segment can start between the fixed split markers shown in Fitness. CUSTOMIZE YOUR RECORDS Choose distances in miles or kilometers, set a distance margin, and enable half marathon, marathon, longest run, longest workout time, and fastest average pace records. FOLLOW YOUR PROGRESS Filter by all time, a recent period, a calendar year, or a custom date range. View the top 20 in each category and sort qualifying runs by race time, race pace, workout time, or workout pace. Workout sorts include runs without usable race timing. EXPLORE EACH RUN Open a workout to see its timing, distance, route map, heart rate, elevation, energy, and weather when those details are available in Health. YOUR DATA STAYS UNDER YOUR CONTROL Run Bests reads running workouts from Apple Health and keeps a local cache on your device. No account, advertising, tracking, or developer-operated server. Run Bests does not write to Health. Requires running workouts in Apple Health. Race and segment estimates depend on the distance and timing data recorded with each workout.