How To Run A Half Marathon Under 1:45: Pace Chart & Plan

Short answer: To break 1:45 in a half marathon (13.109 miles / 21.097 km), you must average 8:00 per mile (4:58 per kilometer). Hitting exactly 8:00/mile brings you across the mat at 1:44:52, leaving just eight seconds of margin. Globally, this time places you in roughly the top 15% to 18% of all road race finishers. If you have already crossed off a sub-2 half marathon, run under 47:30 for 10K, and log 28 to 35 miles a week, 1:44:59 is squarely within your engine's capability.

The challenge at 1:45 is fundamentally different from cracking 2:00. Breaking two hours is mostly an aerobic endurance test: if you don't walk and don't blow up, you usually make it. Breaking 1:45 is a lactate threshold game. At an 8-minute mile, you run right along your aerobic ceiling for 105 consecutive minutes. If your stride rate slips by just four steps per minute around mile 9, your stride lengthens, ground contact time stretches out, and your pace quietly drifts to 8:25 without your heart rate feeling any different.

The sub-1:45 split chart

Targeting 1:44:30 gives you a 30-second buffer for GPS drift, crowded water stations, and tangents.

If you cross 10K slower than 49:50, you are forced to run a sub-49:00 second half into accumulated fatigue. That almost never works. Equally dangerous: going through 5K in 23:30 because the starting corral felt fast. Every second banked too early in a half marathon costs three seconds past mile 10. For a complete breakdown of alternative target paces, review our half marathon pace chart.

Readiness benchmarks: can you run 1:44 right now?

Before launching an 8-week sub-1:45 cycle, check your current fitness against standard race equivalence data (based on Jack Daniels' VDOT formulas and Riegel projections):

• 5K time trial: Sub-22:45 (approx 7:19/mile or 4:33/km). If your 5K PR is 24:30, your top-end aerobic capacity simply cannot support 8:00/mile for 13 miles yet. Spend a block on 5K speed first with our sub-25 5K training plan.
• 10K benchmark: Sub-47:30 (approx 7:39/mile or 4:45/km). This is the cleanest single indicator. If you cannot hold 7:39 pace for 6.2 miles, you cannot hold 8:00 for 13.1. Our sub-50 10K guide lays out the bridge workouts.
• Weekly volume: 28–35 miles (45–56 km) per week across 4–5 runs. Runners attempting sub-1:45 on 18 miles a week almost universally hit the wall around mile 10 because their slow-twitch muscle fibers run out of glycogen storage capacity.
• Longest recent long run: At least 11 miles completed comfortably at an easy, conversational pace (9:15–9:45/mile).

The biomechanics of 8:00/mile: cadence and ground contact

Why do runners with plenty of aerobic fitness miss 1:45 by two or three minutes? The failure mechanism is almost always cadence decay.

At 8:00/mile (12.1 km/h), most efficient recreational runners maintain a stride rate between 172 and 178 steps per minute (SPM). A landmark biomechanical study published in Medicine & Science in Sports & Exercise (Heiderscheit et al., 2011) showed that a modest 5% to 10% increase in step rate immediately decreases foot impact shock, brings the initial foot contact closer to the runner's center of mass, and significantly unloads the knee joint.

When fatigue mounts at mile 9 of a half marathon, your central nervous system tries to conserve energy by slowing your turnover. Your step rate drops from 174 SPM down to 164 SPM. To maintain 8:00/mile at 164 SPM, you are forced to overstride. Overstriding drives your heel into the pavement ahead of your knee, acting as a momentary brake with every footstrike. Within two miles, your quads tighten, your braking forces spike, and your pace bleeds from 8:00 to 8:35.

Locking your turnover to rhythm eliminates this fatigue trap. When your feet are anchored to music at 174 BPM, your cadence cannot quietly decay without you noticing the beat mismatch.

The 8-week sub-1:45 workout plan

This cycle assumes you already possess a consistent base of 25 miles per week. Peak mileage hits 34 miles.

Key workout formats

1. Threshold intervals (T-Pace): Run at 7:40–7:45/mile (4:46–4:49/km). This is 15–20 seconds faster than race pace, elevating your blood lactate threshold so 8:00/mile feels sustainable. See our tempo run guide for physiological specifics.
2. Goal pace rehearsals (HMP): Run sustained blocks at 7:55–8:00/mile (4:55–4:58/km) embedded inside medium-long runs.
3. VO2 max repeat sessions: 800m to 1200m repeats at 7:15–7:25/mile (4:30–4:36/km) to build leg turnover and cardiac output. Check our Yasso 800s guide for pacing mechanics.
4. Aerobic long runs: Run 75–90 seconds slower than race pace (9:15–9:30/mile). Do not race your long runs.

Week-by-week schedule

• Week 1 (26 miles):
  • Tue: 5 miles easy (9:15/mi)
  • Thu: 6 miles total: 2 mi warm-up + 3 × 1 mile at T-Pace (7:45/mi) with 90s jog + 1 mi cool-down
  • Sat: 4 miles easy recovery
  • Sun: 11 miles easy long run (9:20/mi)
• Week 2 (28 miles):
  • Tue: 5 miles easy with 5 × 20s strides
  • Thu: 7 miles total: 2 mi warm-up + 4 miles continuous at Goal Half Marathon Pace (7:58/mi) + 1 mi cool-down
  • Sat: 4 miles easy
  • Sun: 12 miles easy long run
• Week 3 (30 miles):
  • Tue: 5 miles easy
  • Thu: 7 miles total: 2 mi warm-up + 5 × 1000m at 4:35/km (7:22/mi) with 2 min jog + 1 mi cool-down
  • Sat: 5 miles easy
  • Sun: 13 miles long run: first 10 miles at 9:15/mi, last 3 miles at Goal Pace (8:00/mi)
• Week 4 (24 miles - Cutback week):
  • Tue: 4 miles easy
  • Thu: 5 miles total: 1 mi warm-up + 3 miles at 7:55/mi + 1 mi cool-down
  • Sat: 4 miles easy
  • Sun: 11 miles relaxed long run (9:30/mi)
• Week 5 (32 miles):
  • Tue: 6 miles easy
  • Thu: 8 miles total: 2 mi warm-up + 2 × 2.5 miles at T-Pace (7:42/mi) with 3 min jog + 1 mi cool-down
  • Sat: 5 miles easy
  • Sun: 13.5 miles long run: middle 5 miles at steady 8:05/mi
• Week 6 (34 miles - Peak week):
  • Tue: 6 miles easy
  • Thu: 8 miles total: 1.5 mi warm-up + 6 miles continuous at Goal Half Marathon Pace (7:57/mi) + 0.5 mi cool-down
  • Sat: 5 miles easy
  • Sun: 14.5 miles long run: first 11 miles easy, last 3.5 miles progressive down to 7:50/mi
• Week 7 (24 miles - Taper 1):
  • Tue: 5 miles easy with 4 × strides
  • Thu: 6 miles total: 1.5 mi warm-up + 3 × 1 mile at 7:40/mi with 2 min jog + 1.5 mi cool-down
  • Sat: 3 miles shakeout
  • Sun: 10 miles easy long run (9:15/mi)
• Week 8 (19 miles - Race week):
  • Tue: 4 miles total: 1 mi warm-up + 2 miles at Goal Pace (7:58/mi) + 1 mi cool-down
  • Thu: 3 miles easy jog
  • Sat: 2 miles gentle shakeout with 3 strides
  • Sun: Race day (13.1 miles) = 1:44:xx

Race day pacing strategy: the 5-5-3 method

Do not try to run an even split down to the exact second from the starting gun. The cleanest way to manage adrenaline and glycogen is a disciplined three-phase execution:

[Miles 1–5: The Cage] ──> [Miles 6–10: The Machine] ──> [Miles 11–13.1: The Grind]
  Pace: 8:03–8:07/mi         Pace: 7:56–8:00/mi            Pace: 7:50–7:55/mi
  Focus: Restraint           Focus: Cadence lock           Focus: Emptying the tank

• Miles 1 to 5 (The Cage): You will feel completely effortless due to the race taper and adrenaline. Everyone around you will sprint. Hold yourself back. Run 8:03 to 8:07 per mile. Crossing the 5-mile mark in 40:20 leaves you just 20 seconds behind schedule, which you will easily claw back when other runners begin fading.
• Miles 6 to 10 (The Machine): Settle into goal pace: 7:56 to 8:00 per mile. This is where negative split pacing pays dividends. Lock your turnover to 174 BPM music. Take on fuel (one energy gel every 35–45 minutes with water, aiming for 30–45g carbs per hour).
• Miles 11 to 13.1 (The Grind): Your legs will feel heavy, and your mental dialogue will demand a slowdown. Focus entirely on foot turnover. If you keep your feet moving at 174 steps per minute, your stride will not collapse. Drop your pace to 7:50–7:55 for the final mile and drive through the finishing shoot.

How to use BPM-locked audio to hold 8:00/mile

Maintaining a razor-sharp 174 SPM turnover when brain fog sets in is hard to do with willpower alone. A standard shuffle playlist hurts more than it helps: one song plays at 155 BPM and drags your feet down; the next song hits 185 BPM and spikes your heart rate into Zone 4.

Using a rhythmic anchor fixes this. An app like GagaRun analyzes your Apple Music or Spotify library and only plays tracks that match your exact target cadence. Set your target to 174 BPM before you line up in the corral. When you reach mile 8 and your turnover naturally tries to drag toward 165 SPM, the continuous 174 beat serves as a steady acoustic cue, keeping your footfalls light and crisp without you having to constantly stare down at your GPS watch.

Frequently asked questions

What pace is a 1:45 half marathon in km?

A 1:45:00 half marathon requires an average pace of 4:58 per kilometer (4 minutes 58 seconds per km). On a treadmill, this equates to a belt speed of 12.06 km/h (7.5 mph).

What 10K time predicts a sub-1:45 half marathon?

You should be capable of running a 10K in 47 minutes 30 seconds or faster (a 4:45/km or 7:39/mile pace). If your 10K time is above 49:00, your current threshold pace is not fast enough to sustain an 8:00/mile average for 13.1 miles.

Should I take energy gels during a 1:45 half marathon?

Yes. Running for 105 minutes at 85% of your maximum heart rate relies heavily on glycogen. Take one carbohydrate gel (20–25g carbs) 15 minutes before the start, and two gels during the race—one around minute 40 (mile 5) and one around minute 75 (mile 9.5)—always washed down with two sips of plain water.