A sub-1:45 half marathon means holding 4:59/km (8:00/mile) for 21.1 km — the same pace as a sub-3:30 marathon. It is a popular intermediate target, well within reach for runners who have run a few halves and are ready to step up training. The splits above show every kilometer checkpoint for a 1:44:59 finish.
Who this goal is realistic for
Sub-1:45 corresponds to roughly VDOT 44 (Daniels’ Running Formula, 3rd ed.). Realistic entry: a recent 10K under 47:30, or a 5K around 23:00. If you have run 1:50–1:55 halves, sub-1:45 is the right next goal — it is a meaningful step but not a leap. If your 10K is around 50:00, target sub-1:50 first; the gap from 50-min 10K to 1:45 half is wider than the math suggests because the half rewards sustained threshold rather than peak VO2. Confirm with the race predictor and check current fitness via the VDOT calculator.
Training volume needed
Plan for 45–60 km per week at peak (28–37 mpw), with a long run building to 22 km. Twelve weeks of focused training is the standard cycle. Four to five runs per week with one quality threshold session and one long run is the most reliable structure. The runners who break 1:45 most cleanly are the ones who treat their easy days as truly easy and let one quality session per week do the heavy lifting.
Key workouts
- Threshold tempo: 6–8 km at 4:40/km, or 2 x 4 km at the same pace with 2 minutes jog. The bread-and-butter half-marathon workout.
- Goal-pace cruise intervals: 5 x 2 km at 4:59/km with 60 seconds jog. Pace-specific work that prepares you to feel comfortable at 4:59 deep into the race.
- Hill repeats: 8 x 60 seconds uphill, jog down. Builds leg strength and running economy without the recovery cost of pure track work.
- Long run with progression: 18 km starting at 5:30/km, finishing the last 4 km at 4:55/km. Trains the back-half effort that the race demands.
Common pitfalls
The classic sub-1:45 failure is enthusiasm at km 5 — running 4:50/km because the body feels great, then fading to 5:10/km after km 16. The second is over-racing in the build phase. Sub-1:45 is achieved through accumulated threshold volume, not by stacking races. The third is skipping the longer threshold workouts in favor of more intervals — half-marathon performance lives at threshold, not at VO2. The fourth is doing all running on flat surfaces — small hills in training make flat race courses feel easier.
Race-day pacing strategy
Even splits. Aim for the 10 km in 49:30–49:45, settle into 4:59 by km 5, and hold the line. The race typically gets hard around km 14 — that is the point at which patience earlier pays off. Negative split if you have a strong base; even split if you are new to the distance.
Conditions
Heat above 18°C will start to bite. The heat & altitude calculator can adjust your target. Hilly courses (e.g. London if you run in West London, San Francisco) can add 2–4 minutes; pick your goal race accordingly.
Fuel and hydration
One gel at km 7. Water at most aid stations, sports drink at one or two if you tolerate them. Pre-race breakfast and a normal carb-loading day before is enough — there is no need to over-engineer fueling for this distance.
Next steps
Use the splits above as your pace band. The training paces calculator will set your training paces from current VDOT, and the race predictor will show what other distances 1:44 fitness implies. Once sub-1:45 is in the bag, sub-1:40 becomes a one-cycle goal.