2026-09-15 8 min

TDEE Adjustment Calculator

Recalibrate maintenance across change: old vs new weight and activity with delta, percent, plateau diagnosis, and reset targets for the new body.

Calculator

Gender

Units

Height

Same height both ends (or current)

Age

yrs

Age now (both ends)

Before weight

lbs

Starting weight

Before activity

After weight

lbs

Current weight

After activity

Results update live as you type

Status:2,780 to 2,548 kcal-232 kcalTrue plateau math — reset targets down and consider a diet break first

Adjustment Results

Old maintenance2,780 kcal/day

New maintenance2,548 kcal/day

Shift-232 kcal (-8.3%)

DiagnosisTrue plateau math — reset targets down and consider a diet break first

New working target2,148 kcal

Maintenance Ledger

Line	Before	After
Maintenance (TDEE)	2,780 kcal	2,548 kcal
Shift	-232 kcal (-8.3%)
New working target	2,148 kcal
New protein (2.2/kg)	154 g/day

Recommendations

▸Maintenance moved -232 kcal (-8.3%) — true plateau math — reset targets down and consider a diet break first
▸New working target 2,148 kcal with 154 g protein at the new weight
▸Before deepening any cut, take 1-2 maintenance weeks at 2,548 — fatigue masks as plateau constantly
▸Re-adjust every 10 lbs or training-block change — maintenance is a subscription, not a purchase

Results

Normal

Shift

-232 kcal/day

New minus old maintenance

New TDEE

2,548 kcal

Maintenance for the current body and life

Diagnosis

True plateau math — reset targets down and consider a diet break first

What the shift size implies

New Target

2,148 kcal

Working intake reset to the new facts

Protein

154 g/day

2.2 g/kg at the new weight

Mifflin both ends with standard factors, so deltas are pure weight-plus-activity arithmetic. Plateau calls combine the math with adherence checks — numbers first, then honesty.

Visualizations

Old vs New Maintenance (kcal)

2,780Before

2,548After

Shift Magnitude

Shift232kcal

New vs Old

New2,548kcal

Formula

Both snapshots run identical Mifflin math with their own weights and activity factors, so their difference is pure journey arithmetic — mass moved plus lifestyle moved. Thresholds at -200/-50/+200 convert the shift into plateau, drift, hold, or upgrade diagnoses with a reset working target.

Delta = Mifflin(after) - Mifflin(before) with respective activities

Alternative Form

New target = new TDEE - 400; protein = 2.2 x new kg

Variables

Symbol	Name	Unit	Description
Delta	Maintenance shift	kcal/day	New TDEE minus old TDEE
Pct	Relative shift	%	Delta over old maintenance
Diagnosis	Verdict	—	Plateau/drift/hold/upgrade by size
New target	Working intake	kcal	New TDEE minus 400

Explanation

Maintenance follows mass down and activity wherever it goes. Repricing both ends with one method isolates exactly how far targets must move — the number stall forensics always needs first.

Derivation

Old = Mifflin(wB) x fB; new = Mifflin(wA) x fA. Delta = new - old. Target = new - 400. Protein = 2.2 x wA(kg).

Step-by-Step Calculation

Follow each step to understand how the result is calculated from your inputs.

Step 1

Price the before snapshot.

Mifflin at before weight and activity

Before:2,780 kcal

Intermediate: The maintenance old targets assumed

Result: Old TDEE = 2,780 kcal

Step 2

Price the after snapshot.

Mifflin at current weight and activity

After:2,548 kcal

Intermediate: The maintenance current targets must respect

Result: New TDEE = 2,548 kcal

Step 3

Subtract for the shift.

Delta = new - old; percent of old

Delta:-232 kcal

Intermediate: -8.3% of the old maintenance

Result: Shift = -232 kcal/day

Step 4

Diagnose the shift size.

-200 plateau math; -50 meaningful; +200 upgrade

Diagnosis:True plateau math — reset targets down and consider a diet break first

Intermediate: Thresholds separate noise from news

Result: True plateau math — reset targets down and consider a diet break first

Step 5

Reset the working target.

New target = new TDEE - 400

Target:2,148 kcal

Intermediate: Moderate continued pace off the new base

Result: Work from 2,148 kcal with 154 g protein

Step 6

Schedule the next adjustment.

Every 10 lbs or training-block change

Cadence:subscription, not purchase

Intermediate: Re-adjust every 10 lbs or training-block change — maintenance is a subscription, not a purchase

Result: Maintenance moved -232 kcal (-8.3%) — true plateau math — reset targets down and consider a diet break first

Final Answer

-232 kcal/day

Worked Examples

See how the calculator works with different scenarios.

Scenario

A man 175.3 cm, 187 lbs moderate to 154 lbs moderate, age 31.

Inputs

Before:187 lbs moderate

After:154 lbs moderate

Calculation

Old BMR 1793.84 → TDEE 2780. New BMR 1644.16 → TDEE 2548. Delta = -232 (-8.3%). Diagnosis: true plateau math. New target = 2148.

Result

Shift -232 kcal; new target 2,148

Interpretation

Two hundred thirty-two invisible kcal explain the stall completely — reset and resume.

Understanding Your Result

Your Result: Shift: -232 kcal/day

Typical range: Loss shifts typically -100 to -300; activity jumps ±500+; diagnoses at -200/-50/+200 thresholds.

What This Means

The recalibration brief: old and new maintenance, shift with percent, threshold diagnosis, reset working target with protein, and the ledger proving it.

Why It Matters

Stale maintenance is the top cause of mystery stalls and surprise regains. Repricing on new facts converts both into scheduled arithmetic.

Professional Interpretation

Treat -200+ shifts as program events (breaks, resets), small shifts as awareness, upgrades as permission to eat. Re-adjust on subscription cadence.

Threshold triage

Subscription maintenance

Recommendations

•Re-price maintenance per 10 lbs or block change
•-200 shifts earn diet breaks before deeper cuts
•Small shifts need awareness, not overhauls
•Upgrades license eating — take the permission
•Protein follows new weight at 2.2/kg

Educational Content

Introduction

The TDEE Adjustment Calculator re-prices maintenance across your changes. Before/after weight and activity in — shift, diagnosis, reset target, and protein out.

Concept Explanation

Bodies and lives both move; maintenance follows both. Identical math on both snapshots isolates the shift exactly, and thresholds convert its size into the right response.

Applications

▸Diagnosing cut plateaus

▸Resetting post-diet maintenance

▸Pricing activity upgrades

▸Seasonal routine recalibration

▸Post-injury output repricing

▸Bulk-to-cut transitions

Benefits

•Weight and activity shifts separated
•Threshold diagnosis included
•Reset target computed
•Ledger proves the shift
•Break guidance attached

Limitations

•Tissue math only, no adaptation
•Single age both ends
•Snapshot pair per run
•Thresholds are conventions

Best Practices

•Re-run per 10 lbs without exception
•Log activity honestly both ends
•Take breaks on -200+ shifts
•Raise food on upgrades promptly
•Keep protein at new weight

Common Misconceptions

Myth: Plateaus mean broken metabolisms.

Truth: Most plateaus are stale maintenance: the math moved, targets did not. Re-price first, diagnose bodies second.

Myth: Old maintenance returns after dieting.

Truth: Only old habits return it. New bodies keep new numbers until behavior or mass changes them back deliberately.

Myth: Small shifts are not worth tracking.

Truth: Untracked small shifts compound across phases into mystery stalls. Fifty kcal ignored quarterly becomes noticeable yearly.

Practical Tips

•Screenshot old-vs-new with dates in logs
•Take the break the diagnosis suggests
•Raise food fast on upgrades; cut slowly on drifts
•Weigh and measure in the morning before food for repeatable inputs
•Re-run the numbers after every 10-15 lbs of weight change
•Validate any estimate against 2-4 weeks of weight-trend data

Common Mistakes

Deepening cuts into a -200 shift

Big negative shifts already strain recovery; deeper cuts stack fatigue on math. Break at new maintenance first, then resume milder.

Ignoring +500 lifestyle upgrades

New sports need new food promptly. Athletes who diet through upgrades fade, break, and blame training instead of fueling.

One adjustment per year

Bodies move quarterly; annual math guarantees three stale quarters. Subscription cadence or bust.

Using goal weight instead of current weight

Equations describe the body you have, not the one you want. Current weight sets today's burn; goal weight enters only when planning the next phase.

Confusing BMR with maintenance

BMR is the resting floor. Eating at BMR while active is an automatic deficit — multiply by activity (TDEE) before setting intake.

Assumptions

This calculator makes the following assumptions to provide estimates:

Identical method: Mifflin both ends isolates journey math.

Single age: Age held at current for both snapshots.

Honest activities: Both rungs match logged life.

Metric internals: Imperial converts before math.

Threshold conventions: -200/-50/+200 diagnostic edges.

Limitations

Be aware of these limitations when using this calculator:

No adaptation: Beyond-tissue slowdown excluded.

Snapshot pair: Path between endpoints unmodeled.

Age frozen: Multi-year journeys undercount aging slightly.

Convention thresholds: Edges guide, not govern.

Frequently Asked Questions

Answers to common questions about this calculator.

When should I recalculate my TDEE?

Every 10 lbs of change, every training-block switch, every season that moves steps — and immediately when loss stalls 3+ weeks despite adherence.

My weight dropped but TDEE barely moved — why?

Small losses move maintenance ~70 kcal per 10 lbs at moderate activity. Below -50 total, holding course beats overhauling — bank the awareness.

I move more but weigh the same — do I eat more?

Yes if output rose sustainably: +577 for a rung jump funds real food. Undereating new output fades performance within weeks.

What is a diet break and when do I take one?

One to two weeks at new maintenance, indicated on -200+ shifts or 8-12 week cuts. Breaks relieve fatigue and hormonal drag, then cuts resume sharper.

What is TDEE?

Total Daily Energy Expenditure — every calorie burned in 24 hours: basal metabolism (60-75%), food digestion TEF (~10%), daily movement NEAT (15-30%), and deliberate exercise (5-10%). Eating at TDEE holds weight steady.

How is TDEE calculated?

Estimate BMR (usually Mifflin-St Jeor), then multiply by an activity factor: 1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 heavy, 1.9 athlete. The product is maintenance.

What is NEAT and why does it matter?

Non-Exercise Activity Thermogenesis — walking, standing, chores, fidgeting. It varies 200-800+ kcal/day between people and is the most adjustable TDEE lever after formal exercise.

How accurate are TDEE estimates?

Within about 10-15% for most people when activity is honestly rated. Validate by eating at the estimate 2-4 weeks: stable weight confirms it, drift corrects it.

How do I use TDEE to lose weight?

Eat 250-500 kcal below TDEE for 0.5-1 lb weekly loss, keep protein high and lift to protect muscle, and never hold intake below your BMR floor for long.

How do I use TDEE to gain muscle?

Eat 250-350 kcal above TDEE with progressive resistance training and 1.6-2.2 g/kg protein. Bigger surpluses mostly accelerate fat gain, not muscle.

How often should I recalculate TDEE?

Every 4-8 weeks while changing, or per 10-15 lbs. Smaller bodies burn less, so yesterday maintenance becomes today surplus silently.

Related Calculators

Explore more calculators related to this topic.

Related Guides

Deepen your understanding with these educational resources.

Metabolism Basics

BMR, TDEE, and where your calories actually go.

Setting Calories for Fat Loss

From TDEE to deficit without muscle loss.

Protein and Strength While Dieting

Keep the engine while shrinking the chassis.

Glossary

Technical terms used in mortgage calculations explained in plain language.

Delta: New minus old maintenance.
Plateau math: -200+ shifts demanding resets or breaks.
Reset target: New TDEE minus 400 working intake.
Subscription cadence: Per-10-lb re-pricing habit.
BMR: Basal Metabolic Rate: resting calorie burn for vital functions.
TDEE: Total Daily Energy Expenditure: BMR plus all activity and digestion.
Lean body mass: Weight minus fat mass; the engine room equations like Katch use.
Metabolic adaptation: Down-regulation of expenditure during prolonged dieting beyond what tissue loss predicts.

Authoritative References

Trusted sources and standards referenced by this calculator.

Academy of Nutrition and Dietetics — Energy expenditure guidance ACSM — Metabolism and body composition resources PubMed — Predictive equation literature (Mifflin, Harris-Benedict, Cunningham, Owen) FAO/WHO/UNU — Schofield human energy requirements (1985) CDC — Finding a healthy weight and activity guidance MedlinePlus — Metabolism and weight management

Applicable Standards

Mifflin-St Jeor (AJCN 1990)Harris-Benedict original (1919) and Roza-Shizgal revision (1984)FAO/WHO/UNU Schofield requirements (1985)

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Page Information

Last Updated:

2026-09-15

Version:

2.0.0

References:

License:

Free to use for educational and professional purposes.