Marathon Pace Predictor
Plan a marathon by splitting the race into even, negative or positive splits with a target time.
Formula and sources updated · Data sources · 1View algorithm, constants and default inputs (JSON)
About this calculator
Split a target marathon time evenly or apply a small, user-selected positive or negative split. These are arithmetic pacing scenarios only; they do not adjust for course profile, weather, training or individual conditions.
Worked example
calculated with the default values below
Goal time — hours 3 h · Goal time — minutes 30 min · Pacing strategy Even splits Goal time 210.0 min · Overall pace 4:59 · First half split 1:45:00 · Second half split 1:45:00 · Even pace per 5 km 24:53
Method and assumptions
t₁ = T ÷ 2 × (1 − s); t₂ = T ÷ 2 × (1 + s); T = 60h + m Even split s=0; positive split uses a faster first half (−2% time) and slower second half (+2%); negative split reverses them. Course and conditions are not modeled. Split a target marathon time evenly or apply a small, user-selected positive or negative split. These are arithmetic pacing scenarios only; they do not adjust for course profile, weather, training or individual conditions. The references provide context and limitations. They do not validate this page’s illustrative multipliers, lookup values or predictions.
Data sources
The references provide context and limitations. They do not validate this page’s illustrative multipliers, lookup values or predictions.
Disclaimer
These calculators give general mathematical results. They suit study, planning and estimation — verify anything that feeds a graded submission, a published figure or a financial commitment.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
t₁ = T ÷ 2 × (1 − s); t₂ = T ÷ 2 × (1 + s); T = 60h + m
- T
- goal marathon time, min
- t₁
- first-half time
- t₂
- second-half time
- s
- Split factor
- m
- goal minutes
Even split s=0; positive split uses a faster first half (−2% time) and slower second half (+2%); negative split reverses them. Course and conditions are not modeled.
Frequently asked questions
What do positive and negative splits mean?
A positive split allocates less time to the first half and more to the second; a negative split does the reverse. The selected split is a fixed 2% scenario. Course and weather do not change the calculation.
Which inputs and limits apply to Marathon Pace Predictor?
Use the units shown beside each field. These are form limits, not recommended settings. Goal time — hours: 1–10 h; Goal time — minutes: 0–59 min t₁ = T ÷ 2 × (1 − s); t₂ = T ÷ 2 × (1 + s); T = 60h + m Even split s=0; positive split uses a faster first half (−2% time) and slower second half (+2%); negative split reverses them. Course and conditions are not modeled. Split a target marathon time evenly or apply a small, user-selected positive or negative split. These are arithmetic pacing scenarios only; they do not adjust for course profile, weather, training or individual conditions. The references provide context and limitations. They do not validate this page’s illustrative multipliers, lookup values or predictions.
What is a complete worked example for Goal time — hours = 3 h; Goal time — minutes = 30 min?
Inputs: Goal time — hours = 3 h; Goal time — minutes = 30 min; Pacing strategy = Even splits. Calculation: t₁ = T ÷ 2 × (1 − s); t₂ = T ÷ 2 × (1 + s); T = 60h + m. Results: Goal time = 210.0 min; Overall pace = 4:59 min/km; First half split = 1:45:00; Second half split = 1:45:00; Even pace per 5 km = 24:53.