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Weekly Running Mileage Comparison Calculator
Compare this week’s distance with your six-week average. See absolute change, percentage change and long-run share with transparent arithmetic.
Compare running distance without guessing readiness
Use this calculator to describe how your weekly running distance changed. Enter the average of the six complete weeks before the week you are comparing, that week's total, and its longest run. Include zero-mile weeks in the average when you have a complete record. If a week is missing from your log, resolve that gap before treating it as zero.
The result is a distance comparison. It does not calculate physiological training stress, ATL, CTL or TSB, and it does not decide whether you are ready to race or whether an increase is safe. You can use it without connecting an account.
What to enter
| Field | Example | Check |
|---|---|---|
| Previous six-week average | 35 miles | Sum six complete weeks and divide by six |
| Week being compared | 40 miles | Use a complete week, not Monday–Wednesday against a full-week average |
| Longest run | 12 miles | This cannot exceed that week's total |
Record any unusual hills, hard sessions, interruptions or changes in how you felt alongside the numbers. Two equal-distance weeks can contain very different sessions. This tool deliberately does not attach an arbitrary intensity multiplier to them.
The equations
- Distance change = current week − previous six-week average.
- Percentage change = distance change ÷ previous six-week average × 100.
- Longest-run share = longest run ÷ current week's distance × 100.
Distances use miles throughout. Percentage change is undefined when the baseline is zero. Long-run share is not applicable when the current week is zero. Neither situation is replaced with invented mileage.
These are arithmetic descriptions, not validated thresholds for fitness, fatigue or injury. Critiques of training-load ratios explain why numerical associations should not be turned casually into individual injury-prevention prescriptions (Impellizzeri et al., 2020). That paper does not validate this distance comparison as a physiological model.
Worked example: a complete week
Suppose the previous six totals are 30, 35, 40, 30, 35 and 40 miles. Their sum is 210, so the baseline is 35 miles.
This week contains 40 miles, including a longest run of 12 miles:
| Result | Calculation | Value |
|---|---|---|
| Distance change | 40 − 35 | +5 miles |
| Percentage change | 5 ÷ 35 × 100 | +14.3% |
| Long-run share | 12 ÷ 40 × 100 | 30.0% |
The useful follow-up is to compare what made up those miles and your circumstances. The calculator does not label 14.3% or 30% as safe, dangerous or optimal.
Worked example: no running this week
Keep the same 35-mile baseline and enter 0 for both this week and the longest run. The result is −35 miles, −100.0% change, and no applicable long-run share. It does not invent a 40-mile week or interpret time off as proof that you should add a hard session.
If the baseline is also zero, the distance change is still meaningful but a percentage change cannot be calculated.
Keep a useful comparison record
| Week ending | Previous six-week average | Current distance | Longest run | Session/terrain changes | Context and observations |
|---|---|---|---|---|---|
| Example week | 35 mi | 40 mi | 12 mi | Added hills | Compare with a similar week |
| Your week |
Use the same week boundaries and units over time. A single percentage cannot tell you how to adjust training. Persistent symptoms or an injury need appropriate professional assessment, not a calculator verdict.
For a different description of the same week, use the distance-based intensity distribution calculator. Its categories describe the distance you assign to each effort group; they do not supply a readiness score either.
For the separate meaning of ATL, CTL and TSB, read the training-load model explanation. Those models use recorded daily stress; this form compares weekly distance.