Got a goal — sub-12, sub-5, a Kona dream? Set your target finish and your swim & bike, and see the exact run pace you need to hit it. Plan your race backwards. Free, instant.
The smartest way to plan a race is from the finish line back. You can't fully control the swim or bike on race day, but you set a target and a realistic plan for them — and the run is "whatever's left." This tool does that math: it subtracts your planned swim, bike and transitions from your goal, then divides the remaining time over the marathon (or half) to give the run pace you'd need.
A planning estimate, not coaching advice. Build to your goal paces in training and race within your limits.
It depends on your swim and bike. With a 2:00/100m swim, an 18 mph bike and ~14 min of transitions, you'd need roughly a 9:45–10:00/mile marathon. Plug in your real numbers above.
Same idea, half the distances. Set your goal (say 5:30), your swim and bike plan, and the tool shows the half-marathon pace you need to close it out.
On the bike, power (or RPE/heart rate) keeps you from over-biking; this tool plans in speed for simplicity. Translate your target speed to the watts you can hold all day, and keep the run pace honest off the bike.