Train at the right paces.
Run your best half or full marathon.
Most age-group runners run their easy days too fast and their hard days too slow. Plug in your goal race time below and get the exact paces to train at — easy, long, marathon, tempo, intervals, and repeats.
Race & Training Pace Calculator
Enter a recent race result. We'll calculate your VDOT score and Jack Daniels training paces — Easy, Marathon, Threshold, Interval, and Repetition — using the exact formulas from Daniels' Running Formula.
Your Training Paces
—What each training pace is for
Every workout in a smart marathon build has a job. Train each pace where it lives, and the gains stack.
Aerobic base & recovery
The largest chunk of your week. Builds capillaries, mitochondria, and durability. If you can't hold a conversation, you're going too hard.
Endurance with control
Slightly faster than easy on average. Teaches your body to hold form, burn fat, and stay strong in the back half of the race.
Goal race rehearsal
Your actual 26.2 race pace (or HM goal). Used in marathon-pace segments inside long runs to lock in race-day feel.
Lactate clearance
"Comfortably hard" — about the pace you could hold for an hour. Raises the ceiling of how fast you can run before fatigue spikes.
VO₂ max power
3–5 minute reps at roughly 5K race pace. Improves how much oxygen you can deliver and use — the engine size of running.
Speed & economy
Short, fast reps (200–400m) with full recovery. Sharpens neuromuscular firing and makes goal pace feel smoother.
You don't need more miles. You need the right miles.
I coach age-group runners chasing half and full marathon goals — PRs, BQs, first finishes, comebacks after injury. The calculator above is the same starting point I use with every athlete. The real work is in adapting it week to week: adjusting load when life gets busy, dialing back when fatigue stacks up, and pushing hard when the body is ready.
"I'd been training by feel for years and plateauing. Two months in with Coach Justin and I was holding paces I used to be afraid of. PR'd by 6 minutes at the half."— Athlete, age-group runner
Two ways to put these paces to work.
Whether you want a structured plan delivered today or a conversation about your specific goal race — pick the option that fits where you are.