How EveryBand estimates Energy

EveryBand uses energy in two distinct contexts. Energy Reserve is a bounded wellness index combining available daily scores. Energy expenditure describes estimated or imported calorie values. A reserve score is not a calorie balance, and calorie expenditure is not a measurement of how energetic you feel.

This page describes the documented implementation reviewed on 15 October 2026. Your installed beta may differ. These calculations are wellness estimates, not medical measurements, a metabolic test or a reason to ignore symptoms or hunger.

The current method combines available capacity and load context. Higher Recovery and Sleep contribute positively. Higher load pressure and Stress reduce the respective components.

Weights are normalized over the components that exist. Missing Recovery is not treated as zero. The calculation requires at least two available inputs, including a capacity input, Sleep or Recovery, and a load input, Strain or Stress. Without both kinds of evidence, Energy Reserve stays unavailable.

The resulting weighted average is rounded and bounded between zero and 100. These weights are product choices; they do not establish the fraction of your body's actual energy explained by each signal.

Energy Reserve summarizes the current available context; it does not maintain a literal stored charge. This implementation does not carry a measured battery balance from yesterday into today. An update can change the value when more Sleep, Recovery or daytime evidence becomes available.

The Strain index can exceed 100, while the internal load-pressure input used here is capped at 100. Those values have different roles. The Stress estimate also depends on coverage and filtering, so a reserve value does not prove a complete continuous day of monitoring.

A higher reserve does not guarantee that you can safely add exercise. A lower reserve does not diagnose illness, fatigue or inadequate nutrition. It is context from the app's independent scores, whose own assumptions and limitations also apply.

Available calorie records can come from optional Apple Health input or supported local estimation. These paths should remain identifiable: a value supplied by another app is not automatically a measurement calculated by EveryBand.

The local prediction path uses required profile information and available heart-rate/activity observations. The documented code includes revised Harris–Benedict basal coefficients and heart-rate activity coefficients associated with published prediction work. Missing profile fields or unsupported observations can leave an estimate unavailable; access to Full does not repair the input gap.

The Harris–Benedict reevaluation concerns predicted resting energy requirements. Keytel and colleagues studied heart-rate-based energy prediction during controlled submaximal exercise. Those papers explain relevant prediction methods. They do not validate EveryBand's whole-day estimates, its sensors or every activity type.

An equation estimates expenditure from a limited set of inputs. It does not directly measure oxygen consumption or individual metabolism. Sensor fit, heart-rate error, incomplete wear, profile assumptions and the kind of activity can all change the result. An age-based maximum-heart-rate estimate is not a measured personal maximum.

Active and basal energy are also different categories. Adding recorded categories without understanding their origin can create misleading totals. When using multiple sources, check what each app writes and what Health makes available; see the Health sync guide.

The displayed precision should not be mistaken for equal precision in physiology. Avoid using a calorie estimate as an exact prescription for eating, weight change or medical treatment. EveryBand makes no claim that its predictions are more accurate than another app's.

Energy Reserve needs its minimum mix of capacity and load inputs. Calorie estimation needs its own profile and observation evidence. One can be available while the other is absent. A successful Bluetooth connection or permitted Health export does not independently satisfy either calculation.

Algorithm changes, new records and changed sources can affect both values. Check the installed build, the source and the observation time before comparing results. EveryBand is independent and is not affiliated with, endorsed by or sponsored by WHOOP, Apple or Bevel.

Written by EveryBand. Published October 16, 2026; reviewed October 16, 2026. Product descriptions are subject to the installed build; third-party features and terms may change.

• Keytel et al.: Prediction of energy expenditure from heart rate monitoring
• Roza and Shizgal: The Harris Benedict equation reevaluated

EveryBand is an independent app and is not affiliated with, endorsed by, or sponsored by WHOOP, Apple, or Bevel. Third-party product names and trademarks belong to their respective owners and are used only for factual compatibility and interoperability descriptions.

Other app and device names belong to their owners. EveryBand is also independent of Sixteen and its publisher. For corrections, contact EveryBand.

• How the estimates workRead the full explanation.
• How EveryBand calculates RecoveryEveryBand Recovery combines nightly RMSSD, resting heart rate and Sleep with personal history. It needs the current night and two prior complete baseline nights.
• How EveryBand calculates SleepEveryBand Sleep combines duration against estimated need, regularity, efficiency and sleep stress. Stages and missing data have separate limits.
• How EveryBand calculates StrainEveryBand Strain uses covered heart-rate intensity and time, considering movement and steps without counting the same effort repeatedly. Its index can exceed 100.
• How EveryBand estimates StressEveryBand Stress is a 0–100 physiological estimate from heart rate relative to rest, with available HRV context and movement filtering. It does not measure emotions.
• Missing Apple Health data? Check the path in orderTroubleshoot EveryBand Health imports and exports by checking the original record, permissions, source choice, timing and locked-phone behavior.