Skip to main content

Race Finish Time Predictor

Health & Body

5K/10K/half/full marathon — Riegel formula

Quick Answer

Race Finish Time Predictor: 5K/10K/half/full marathon — Riegel formula. T₂ = T₁ × (D₂ ÷ D₁)^1.06.

e.g. 50:00 or 1:45:30

Predicted marathon finish

3:50:01

Pace 5'27"/km · Solid runner

Predicted time3:50:01
Target pace5'27"/km
Current pace5'00"/km
LevelSolid runner

Steps

  1. 1Known: 10km in 50:00 → pace 5'00"/km
  2. 2Riegel: T₂ = 50:00 × (42.195/10)^1.06 = 3:50:01
  3. 3The 1.06 exponent models fatigue: pace slows from 5'00" to 5'27"/km
  4. 4Marathon reality check: add 5-10% unless your weekly mileage exceeds 50km — the wall at 30km is glycogen depletion, not fitness

Split plan at 5'27"/km (even pace)

PointElapsedNote
10.5 km57:30Settle in — hold back 5-10s/km
21.1 km1:55:00Halfway — effort should feel controlled
31.6 km2:52:30The race starts here — stay patient
42.2 km (finish)3:50:01Final push — empty the tank
The Riegel formula (1977) remains the gold standard for race prediction: T₂ = T₁ × (D₂/D₁)^1.06. Its limits: predictions stretch best between similar distances (10K→half is safer than 5K→marathon), and the marathon demands specific endurance training that raw speed can't substitute. Negative split (second half faster) is how PBs are made — start 10-15s/km slower than target pace.

Was this tool helpful?

Average 1 · 1 rating

How to Use

  1. Enter body metrics: fill height, weight, age etc. as prompted by the Race Finish Time Predictor.
  2. Read value and grade: results appear instantly with an authority-based classification.
  3. Check reference tables: confirm your range and healthy targets against the tables on this page.
  4. Back-solve your goal: adjust inputs to see what it takes to reach a target.

Key Points

  • Race Finish Time Predictor is a free online health tool — open and use, no sign-up.
  • All calculations run locally in your browser; your data never leaves the device.
  • Key capability: 5K/10K/half/full marathon — Riegel formula.
  • Results come with formulas and reference tables so you can verify every number.

Formula & How It Works

Riegel formula

T₂ = T₁ × (D₂ ÷ D₁)^1.06
Predicts finish time from a known race result

FAQ

How do I use the Race Finish Time Predictor?
Open the page and fill in the input fields — results update automatically. 5K/10K/half/full marathon — Riegel formula.
Are the results accurate?
Results follow published international standards (WHO, ACE, IOM) and are for reference only.
Can this replace medical advice?
No. Always consult a qualified healthcare professional for health decisions.
Is it free? Do I need to sign up?
Completely free. No registration, login or download required.
Does it work on mobile?
Yes. The responsive design works on all devices.

Related Tools

Related Guides

Source & Updates

Based on WHO, ACE, IOM and other published international standards. Last updated: 2025-07

Authoritative sources:

Last updated:

Formulas and content on this page are reviewed by the YiJianSuan team. For reference only — official sources prevail.

Maintained and periodically reviewed by the YiJianSuan editorial team — review process in ourEditorial Policy.

Cite this page: YiJianSuan. Race Finish Time Predictor[EB/OL]. https://www.yijiansuan.com/en/c/health/marathon

Results provided by this tool are for reference only and do not constitute professional advice.