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 shows your personal best running times drawn from your health data. Outside of a race, runners rarely hit the exact same distance twice. Your "5-mile run" might be 5.1 miles today and 5.05 miles tomorrow. Because of that variation, Run Bests brackets runs within a certain range together. Just set a target distance (in miles or kilometers) and choose a "margin of error." For example, if you want to find your fastest 5-mile run, set a 0.25 margin and Run Bests will instantly scan your selected date range and pull every run between 5.0 and 5.25 miles into one clean, sortable list. KEY FEATURES * Distance Bracketing Group your past runs using a custom margin of error (0, 0.25, 0.5, or 1) so no near-miss gets left out. Margin is applied upward only — a 4.99-mile workout won't count toward 5-mile until it crosses the line. * Race Time vs. Workout Time For each qualifying workout, see both the time you crossed the exact target distance (race time, GPS-derived) and the full elapsed workout time. * Best Segment Paces Find your fastest contiguous 1 km, 1 mile (or any distance you pick) found anywhere inside any run — even if your fastest mile happened in the middle of a long marathon. * Major Races + Overall Records Toggle Half Marathon and Marathon. Plus longest distance, longest duration, and fastest average pace. *Custom Date Filters Browse PRs across all time, the last 30 / 90 days, the last year, a single year, or any custom date range. Watch yourself improve across a training cycle. *Tap-to-Sort Leaderboards Inside each category, top 20 by Race time, Race pace, Workout time, or Workout pace. * Privacy by Design Run Bests reads your running workouts from Apple Health and stores a private local cache on your device. Nothing leaves your phone.