TDEE for runners can be estimated as (BMR × non-running activity factor) + running calories. Choose an activity factor that describes your day without the run, then add roughly 100 calories per mile run. For example, a 1,800-calorie BMR, a 1.2 activity factor, and a 5-mile run produce an estimated TDEE of 2,660 calories.
The TDEE Formula for Runners
Use this calculation for each day:
TDEE = (BMR × non-running activity factor) + (running miles × calories per mile)
The first term estimates what you burn from basic body functions and ordinary non-running activity. The second term adds the run explicitly, so mileage remains visible in the calculation.
Step 1: Calculate Your Non-Running TDEE
Start with your BMR, then multiply it by an activity factor based on what you do outside running:
- Mostly seated day: BMR × 1.2
- Light non-running activity: BMR × 1.375
- Moderate non-running activity: BMR × 1.55
These factors are approximations. The important part is to select one that excludes the running you plan to add separately.
Step 2: Add the Run
Use running calories ≈ miles × 100 as a simple rule:
- 3 miles ≈ 300 calories
- 5 miles ≈ 500 calories
- 10 miles ≈ 1,000 calories
The 100-calorie rule is intentionally round. If you already use a different calories-per-mile estimate, substitute that number without changing the structure of the formula.
Example: A 5-Mile Run on a Desk Day
Suppose your BMR is 1,800 calories and the rest of your day is mostly seated.
Non-running TDEE:
1,800 × 1.2 = 2,160 calories
Running calories:
5 miles × 100 = 500 calories
Estimated run-day TDEE:
2,160 + 500 = 2,660 calories
On a rest day with the same non-running activity, the estimate would remain 2,160 calories. The run adds 500 calories rather than changing the activity multiplier for the whole day.
Example: Four Runs Across One Week
Suppose your BMR is 1,500 calories and your non-running activity factor is 1.375.
Daily non-running TDEE:
1,500 × 1.375 = 2,062.5, rounded to 2,063 calories
Now add four 3-mile runs during the week:
4 runs × 3 miles × 100 = 1,200 running calories per week
Estimated weekly TDEE:
(2,062.5 × 7 days) + 1,200 = 15,637.5, rounded to 15,638 calories per week
Estimated daily average:
15,637.5 ÷ 7 = 2,233.9, rounded to 2,234 calories per day
That average is useful for weekly arithmetic, while the daily method preserves the difference between run days and rest days. To replace the example inputs with your BMR, activity, and mileage, run your own numbers in the TDEE calculator.
Why Not Just Raise the Activity Multiplier?
Raising the multiplier hides the run inside a broad activity category. It can also produce the same added calories for very different running distances.
For a BMR of 1,800 calories, changing the factor from 1.2 to 1.55 adds:
1,800 × (1.55 − 1.2) = 630 calories
That 630-calorie increase does not tell you whether the runner completed 3 miles or 10 miles. Adding mileage separately would produce about 300 calories for 3 miles or 1,000 calories for 10 miles, making the assumption explicit and reducing the chance of counting the same exercise twice.
Is 100 Calories per Mile Exact?
No. 100 calories per mile is a rough calculation shortcut, not a fixed value for every runner or every route. Actual estimates vary with body mass, grade, terrain, running efficiency, and the method used to calculate energy expenditure.
If your preferred estimate is 85 calories per mile, a 6-mile run becomes 6 × 85 = 510 calories. If it is 120 calories per mile, the same run becomes 6 × 120 = 720 calories.
How Does This Relate to 3,500 Calories per Pound?
The common arithmetic relationship is:
3,500 calories ≈ 1 pound of energy equivalent
First calculate the energy gap for each day:
Daily energy gap = TDEE − calories consumed
If estimated TDEE is 2,660 calories and the recorded intake is 2,260 calories, the arithmetic gap is 400 calories. Repeated for seven days, that becomes 400 × 7 = 2,800 calories, and 2,800 ÷ 3,500 = 0.8 pound of energy equivalent.
This is an accounting conversion, not a guarantee of an observed weight change. TDEE, running calories, food totals, and the 3,500-calorie relationship are all estimates.
CalBurndown turns the same arithmetic into a daily calorie budget you can spend down, with runs added back as explicit activity rather than buried inside a multiplier.