The short version
Your total daily energy expenditure (TDEE) is two things added together: the calories you burn just by being alive (BMR, which runs 24/7, including sleep) and the calories you burn moving (active calories). We compute BMR from a published equation personalized to you, and active calories from the best signal available — heart rate first, then your logged sessions, then a movement-type (MET) estimate — always being careful never to count your baseline twice. This page lays out the BMR equation, the MET table, the fallback order, and exactly how the daily total is assembled.
Why we're publishing this
A "calories burned" number is only meaningful if you know what went into it. This page documents the resting and activity side of the ledger; the Calories From Heart Rate page covers the primary active-calorie method in detail. Together they describe your complete daily energy budget.
TDEE = baseline + active
The whole model is one honest equation:
TDEE = BMR (across the whole day) + active calories (above baseline)
The trick is computing each part correctly and not double-counting the overlap — which is most of what this page is about.
Basal metabolism (BMR)
Your basal metabolic rate is the energy your body spends at complete rest just to keep you running — and it's the large majority of most people's daily burn. We compute it from the Schofield (1985) equations,[1] which predict resting energy from body weight, banded by age and sex:
Men
| Age | kcal/day |
|---|---|
| 18–30 | 15.057 × weight_kg + 692.2 |
| 31–60 | 11.472 × weight_kg + 873.1 |
| 60+ | 11.711 × weight_kg + 587.7 |
Women
| Age | kcal/day |
|---|---|
| 18–30 | 14.818 × weight_kg + 486.6 |
| 31–60 | 8.126 × weight_kg + 845.6 |
| 60+ | 9.082 × weight_kg + 658.5 |
The Schofield equations are the basis of the World Health Organization's energy-requirement standards — a well-validated, widely used choice. We convert the daily figure to a per-minute rate and accrue it across every minute of your day, including sleep, because your basal metabolism never clocks off. Missing inputs fall back to sane population defaults (≈70 kg, age 30), which we'd always rather replace with your real profile.
Active calories: best available signal wins
Active calories are everything above baseline. We compute them from the best signal we have, in a strict priority order:
Tier 1 — Heart rate (preferred)
When heart-rate coverage is good, we use the Keytel heart-rate method.[3] For a workout, a couple of valid readings is enough. For your whole day, heart rate must cover at least 50% of the day before we trust it for your total.
Tier 2 — Your logged sessions
If heart rate is too sparse for the day, we sum the calories from your individual logged workouts and activities (each computed by the best method available to it), and subtract the baseline metabolism that was already accruing during those minutes — so what's left is genuinely the active portion.
Tier 3 — Movement-type estimates (METs)
When a session has no usable heart rate at all, we fall back to METs — the standard "metabolic equivalent" measure of an activity's intensity, from the Compendium of Physical Activities.[2] The formula is the textbook one:
calories = MET × weight_kg × hours
We pick the MET value from what we know about the session:
- Strength sets scale with how heavy the effort was — roughly 6 METs for low-rep heavy sets, 5 for moderate, 4 for high-rep work.
- Cardio with distance and pace is estimated as running or cycling at the appropriate MET for the computed speed (e.g. an 8-mph run ≈ 10 METs; 16-mph cycling ≈ 8 METs).
- Yoga and flow work sit around 3.5 METs.
- Anything else falls back to a general ~5-MET estimate so a logged session is never worth zero.
Defining "your day"
Active calories and BMR are summed over a single daily window. We define that window around your sleep, not the clock, because your metabolic day really begins when you wake:
- Start: when you woke from last night's main sleep.
- End: when you start tonight's sleep (or now, if that hasn't happened yet).
- No sleep data? We fall back to a plain midnight-to-midnight window.
This sleep-anchored window is what makes your running daily total feel right — it builds through your waking hours rather than resetting at an arbitrary midnight.
Not counting your baseline twice
This is the subtle part most calorie trackers get wrong or hide. Heart-rate calories already include baseline metabolism (you're always burning your BMR, even mid-run). If we simply added the heart-rate total to a separately-computed full-day BMR, we'd count the overlap twice and inflate your burn.
So for the minutes heart rate covers, we replace the baseline estimate with the heart-rate measurement, and only add separately-computed BMR back for the uncovered minutes:
TDEE = BMR(full day) − BMR(covered minutes) + heart-rate calories(covered minutes) active calories = TDEE − BMR (never negative)
The session-based fallback does the same thing in reverse — it adds only the above-baseline active portion of each session on top of the full-day BMR. Either way, your baseline is counted exactly once.
What we're honest about
What we’re honest about
- BMR is an estimate, not a measurement. Schofield is population-fit; individual basal rates vary with body composition, genetics, and history. It's a strong, standard starting point — not a metabolic chamber.
- MET estimates are coarse. A MET value is a population average for an activity type; it can't see how hard you went. The MET tier is a fallback for exactly the cases where we have no better signal, and it's our least precise method.
- Garbage in, garbage out on profile data. Wrong weight, age, or sex skews everything downstream. Keeping your profile accurate is the single biggest thing you can do for these numbers.
- Strength calories are conservative. Both the heart-rate and MET methods under-read pure lifting, where energy cost is real but heart rate stays low and movement is brief. We note the same blind spot in Strain.
- It's a budget, not a contract. Use the trend and the relative magnitude, not the last digit. The value is in watching it move with your training, not in treating any single day's total as exact.
How this metric evolves
This is the energy methodology v1.0. We expect to refine the BMR personalization, expand and sharpen the MET mappings, and improve how the tiers blend. Material changes will be noted here.
References
- [1] Schofield W.N. Predicting basal metabolic rate, new standards and review of previous work. Human Nutrition: Clinical Nutrition, 39 Suppl 1:5–41 (1985). The Schofield equations were adopted by the 1985 FAO/WHO/UNU Energy and Protein Requirements report and predict BMR from body weight, banded by age and sex.
- [2] Ainsworth B.E., et al. 2011 Compendium of Physical Activities: a second update of codes and MET values. Medicine & Science in Sports & Exercise, 43(8):1575–1581 (2011); Herrmann S.D., et al. 2024 Adult Compendium of Physical Activities: a third update of the energy costs of human activities. Journal of Sport and Health Science, 13(1):6–12 (2024). The standard reference for the MET (metabolic equivalent) cost of activities. link
- [3] Keytel L.R., et al. Prediction of energy expenditure from heart rate monitoring during submaximal exercise. Journal of Sports Sciences, 23(3):289–297 (2005). doi:10.1080/02640410470001730089. See the Calories From Heart Rate page for the full heart-rate method.
This document describes a proprietary metric built on published equations. The reasoning and application are documented in the interest of transparency; the underlying implementation is our own.