Methodology
How the TDEE calculator works
The equations, activity multipliers, and page-level adjustments TDEEHQ uses — and what they do not prove.
This page describes the math in the public calculator. It is an explanation of the code, not a medical claim and not a measured metabolic test. Read the disclaimer before you change how you eat.
Mifflin-St Jeor
When body fat is left blank, resting burn (BMR) uses Mifflin-St Jeor. Weight is kilograms, height is centimetres, age is years:
- Male: (10 × kg) + (6.25 × cm) − (5 × age) + 5
- Female: (10 × kg) + (6.25 × cm) − (5 × age) − 161
The sex term is the only difference. Age is already inside this equation, including on the over-40 page.
Katch-McArdle
If you enter a body-fat percentage, the calculator switches. Lean mass is weight × (1 − body fat / 100). BMR is 370 + (21.6 × lean mass). Sex and age are not in that equation. The switch happens only when body fat is filled in.
Activity multipliers
TDEE is BMR times one activity factor. These are the factors in the calculator, with the label shown in the menu:
| Level | Factor | Menu hint |
|---|---|---|
| Sedentary | ×1.2 | Desk job, little or no exercise |
| Lightly active | ×1.375 | Light exercise 1–3 days / week |
| Moderately active | ×1.55 | Moderate exercise 3–5 days / week |
| Very active | ×1.725 | Hard exercise 6–7 days / week |
| Athlete | ×1.9 | Two-a-days or physical job |
The factor is a stand-in for the whole week, including typical training. The calculator does not add a separate exercise-calorie field on top.
Accuracy
The calculator describes formula estimates as typically within about ±10% for many adults. That is a rule of thumb printed on the tool, not a guarantee for a specific person. Two weeks of morning weights, averaged, is how the site suggests checking the estimate. Move intake by about 100–200 kcal if the trend is clearly the wrong way.
Limitations
- The equations do not see day-to-day NEAT, sleep, stress, or unlogged food.
- They are not adjusted here for pregnancy, illness, or medication.
- Body-fat inputs are only as good as the measurement you type in.
- A wearable’s exercise calories are not part of this math. Adding them yourself double-counts training that the activity factor already represents.
- Teen estimates use the same adult equations and are only a rough guide. The teens page says so.
Adjustments on variant pages
Some pages multiply the formula TDEE by an extra factor after the equation runs. That factor is chosen from the controls on that page. It does not change Mifflin-St Jeor or Katch-McArdle. The unmodified formula result is shown next to the adjusted figure. Full notes below are the same strings the calculator shows for each option.
TDEE Calculator for Adults Over 40
Pick your decade and how you train. Lifting regularly removes most of the penalty; the formula already includes an age term, so the extra correction is deliberately small.
| Option | Factor | Note shown on the page |
|---|---|---|
| 40–49 · Lift 2+ × / week | ×1.00 | No downward adjustment — regular lifting keeps your lean mass, and your TDEE, close to the formula. |
| 40–49 · Active, no lifting | ×0.98 | A 2% trim. Cardio keeps you active but does not stop lean-mass loss, which lowers resting burn year on year. |
| 40–49 · Mostly sedentary | ×0.97 | A 3% trim — the largest we apply. Without resistance training, both muscle and everyday movement tend to fall in this decade. |
| 50–59 · Lift 2+ × / week | ×0.99 | A small 1% trim. Lifting protects most of your muscle; the remainder reflects typical NEAT decline in your decade. |
| 50–59 · Active, no lifting | ×0.96 | A 4% trim. Cardio keeps you active but does not stop lean-mass loss, which lowers resting burn year on year. |
| 50–59 · Mostly sedentary | ×0.95 | A 5% trim — the largest we apply. Without resistance training, both muscle and everyday movement tend to fall in this decade. |
| 60–69 · Lift 2+ × / week | ×0.98 | A small 2% trim. Lifting protects most of your muscle; the remainder reflects typical NEAT decline in your decade. |
| 60–69 · Active, no lifting | ×0.95 | A 5% trim. Cardio keeps you active but does not stop lean-mass loss, which lowers resting burn year on year. |
| 60–69 · Mostly sedentary | ×0.93 | A 7% trim — the largest we apply. Without resistance training, both muscle and everyday movement tend to fall in this decade. |
| 70+ · Lift 2+ × / week | ×0.97 | A small 3% trim. Lifting protects most of your muscle; the remainder reflects typical NEAT decline in your decade. |
| 70+ · Active, no lifting | ×0.94 | A 6% trim. Cardio keeps you active but does not stop lean-mass loss, which lowers resting burn year on year. |
| 70+ · Mostly sedentary | ×0.93 | A 7% trim — the largest we apply. Without resistance training, both muscle and everyday movement tend to fall in this decade. |
TDEE Calculator for Weight Loss
Pick how hard you want to cut. Larger deficits look faster on paper and usually cost adherence and muscle.
| Option | Factor | Note shown on the page |
|---|---|---|
| Gentle (−300 kcal) | ×0.92 | About a 300 kcal cut from estimated maintenance — easiest to sustain. |
| Standard (−500 kcal) | ×0.88 | About a 500 kcal cut — the usual sweet spot for 0.25–0.5 kg per week. |
| Aggressive (−700 kcal) | ×0.84 | About a 700 kcal cut. Use for short blocks; watch energy, sleep and lifts. |
TDEE Calculator for Muscle Gain
Newer lifters can use a slightly larger surplus. Advanced lifters stay closer to maintenance.
| Option | Factor | Note shown on the page |
|---|---|---|
| Novice | ×1.12 | About a +250–350 kcal surplus — novices partition energy into muscle more easily. |
| Intermediate | ×1.08 | About a +200–300 kcal surplus — the usual lean-gain target. |
| Advanced | ×1.05 | About a +100–200 kcal surplus — larger surpluses mostly add fat at this stage. |
TDEE Calculator for Bulking
Hardgainers sometimes need more. Everyone else should stay closer to a lean bulk.
| Option | Factor | Note shown on the page |
|---|---|---|
| Controlled bulk (+300) | ×1.10 | About +300 kcal — cleaner bulk with less fat to cut later. |
| Classic bulk (+400) | ×1.14 | About +400 kcal — classic size push; watch waist monthly. |
| Hardgainer (+500) | ×1.18 | About +500 kcal — use only if a leaner surplus truly failed. |
TDEE Calculator for Maintenance Calories
Same estimated TDEE — choose how tightly you want to treat it.
| Option | Factor | Note shown on the page |
|---|---|---|
| Exact estimate | ×1.00 | No adjustment — use the formula TDEE as your maintenance starting point. |
| Slight buffer (−100) | ×0.97 | About −100 kcal for people who under-count oils, bites and pours. |
| Slight buffer (+100) | ×1.03 | About +100 kcal if you are very fidgety / high-NEAT and estimates run low. |
TDEE Calculator for Men
A light adjustment based on how you actually train — not how you identify online.
| Option | Factor | Note shown on the page |
|---|---|---|
| Lift-focused | ×1.02 | Slight upward nudge — lifting days often under-counted in “moderate” weeks. |
| Mixed training | ×1.00 | No extra adjustment — formula TDEE as estimated. |
| Cardio / steps focus | ×0.98 | Slight downward nudge if lifting is absent and NEAT is the main burn. |
TDEE Calculator for Women
We bias deficit size gentler by default — you can still choose a standard cut.
| Option | Factor | Note shown on the page |
|---|---|---|
| Fat loss focus | ×0.90 | About a 300–400 kcal deficit — protective of training and hormones for many women. |
| Maintain | ×1.00 | No adjustment — estimated maintenance. |
| Build muscle | ×1.06 | About a +150–250 kcal surplus for lean gain. |
TDEE Calculator for Teens
Sports seasons swing burn a lot. Pick the current average week.
| Option | Factor | Note shown on the page |
|---|---|---|
| School + light activity | ×0.98 | Slight downward nudge if the week is mostly sedentary outside PE. |
| Active / recreational sport | ×1.00 | No extra adjustment. |
| Competitive sport | ×1.05 | Slight upward nudge for heavy practice weeks — still verify with energy, mood and performance. |
Desk Job TDEE Calculator
Tell us how much you actually move outside the chair.
| Option | Factor | Note shown on the page |
|---|---|---|
| Mostly chair + commute | ×0.97 | Slight downward nudge — very low NEAT weeks often overshoot on “lightly active”. |
| Walk breaks / 7–9k steps | ×1.00 | No extra adjustment — sedentary base with decent steps. |
| Desk + 3–5 gym sessions | ×1.04 | Slight upward nudge for training days — keep the workday tier honest. |
Shift Worker TDEE Calculator
Rough correction for how chaotic the week is.
| Option | Factor | Note shown on the page |
|---|---|---|
| Stable shifts | ×1.00 | No extra adjustment. |
| Rotating / mixed | ×0.98 | Slight downward nudge — rotating sleep often lowers spontaneous movement. |
| Heavy nights | ×0.96 | Larger downward nudge when nights crush NEAT and recovery. |
TDEE Calculator for 10,000 Steps a Day
Be honest about the weekly average, not your best day.
| Option | Factor | Note shown on the page |
|---|---|---|
| ~7–8k steps | ×0.98 | Slight downward nudge if your “10k” week is really closer to 7–8k. |
| ~10k steps | ×1.00 | No extra adjustment — moderate base for a true ~10k average. |
| ~12k+ steps | ×1.03 | Slight upward nudge for consistently high daily walking. |
Physical Job TDEE Calculator
Match the physical demand of the average shift.
| Option | Factor | Note shown on the page |
|---|---|---|
| On feet, light carrying | ×0.98 | Slight downward nudge if the job is walking-heavy but not strenuous lifting. |
| Labour / lifting | ×1.00 | No extra adjustment on top of a high activity base. |
| Heavy / all-day grind | ×1.04 | Slight upward nudge for truly grinding physical days. |
TDEE Calculator for Runners
Pick the load that matches this training block.
| Option | Factor | Note shown on the page |
|---|---|---|
| Base / easy volume | ×0.98 | Slight downward nudge for easy-volume blocks. |
| Build with workouts | ×1.00 | No extra adjustment on a very-active base. |
| Peak / high mileage | ×1.05 | Slight upward nudge for high-mileage peak weeks. |
TDEE Calculator for Lifters
How many hard lifting days land in a normal week?
| Option | Factor | Note shown on the page |
|---|---|---|
| 2 days / week | ×0.98 | Slight downward nudge if lifting is twice weekly and the job is quiet. |
| 3–4 days / week | ×1.00 | No extra adjustment. |
| 5–6 days / week | ×1.03 | Slight upward nudge for high-frequency lifting blocks. |
TDEE Calculator for Cyclists
Choose the block you are in right now.
| Option | Factor | Note shown on the page |
|---|---|---|
| Recovery / low hours | ×0.96 | Downward nudge for recovery weeks — do not eat like camp week. |
| Build / steady hours | ×1.00 | No extra adjustment. |
| High volume / camp | ×1.06 | Upward nudge for high-volume weeks; still verify with energy and weight trend. |
TDEE Calculator for Athletes
Energy availability should rise with load.
| Option | Factor | Note shown on the page |
|---|---|---|
| Off-season | ×0.96 | Downward nudge — do not eat like peak season in the off-season. |
| Prep / preseason | ×1.00 | No extra adjustment on a high-activity base. |
| In-season | ×1.04 | Upward nudge to protect in-season energy availability. |
What we do not claim
Publishing these equations is not a dietitian endorsement, and it is not a statement that an academy or society recommends this website. Protein ranges shown on variant pages are targets printed in the interface. A citation for them belongs in the source list below once you add one.
Sources
These are placeholder references. Add a full citation before relying on them.
- Mifflin et al. 1990. [ADD FULL CITATION]
- Katch-McArdle. [ADD FULL CITATION]
- ISSN protein position stand. [ADD FULL CITATION]