The Ultimate Guide to Calculating Your Calorie Deficit
· by The Calorie Deficit Diet
If you’ve ever wondered “How big should my calorie deficit be?” this guide is for you. Below you’ll learn a simple, accurate way to calculate your deficit using BMR (Basal Metabolic Rate) and TDEE (Total Daily Energy Expenditure), see a complete worked example, set protein & macro targets, and troubleshoot plateaus—so you can lose fat consistently without wrecking your energy or sanity.
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What is a calorie deficit?
A calorie deficit is when you consistently eat slightly fewer calories than your body burns. Your body then uses stored energy (mostly fat) to make up the difference. The art is picking a deficit that’s large enough to see progress, but small enough to sustain.
As a rule of thumb, aim to lose roughly 0.5–1.0% of body weight per week. Faster is possible at higher body weights, but pushing too hard usually backfires (hunger, low energy, and rebound overeating).
You can calculate your deficit with three numbers: BMR → TDEE → Target Calories. Let’s do it step by step.
Step 1: Calculate your BMR
Your Basal Metabolic Rate (BMR) is the calories your body would burn in a day at rest. The most-used formula for the general population is the Mifflin–St Jeor equation:
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Don’t want to do the math by hand? Use our fast tool here:
Open the TDEE & Deficit Calculator (auto‑converts between lbs/in and kg/cm).
Step 2: Estimate your TDEE
Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor:
| Activity Level | Multiplier | What it looks like |
|---|---|---|
| Sedentary | 1.2 | Desk job, little formal exercise |
| Lightly active | 1.375 | 3–4 light workouts or 6–8k steps/day |
| Moderately active | 1.55 | 4–5 moderate workouts or 8–12k steps |
| Very active | 1.725 | Physical job or daily hard training |
| Extra active | 1.9 | Athlete, two‑a‑days, or very high NEAT |
Step 3: Choose a smart deficit
Pick a deficit you can repeat week after week:
- Gentle (≈10–15%): Best for busy or leaner folks; easiest to sustain.
- Moderate (≈20%): Great balance of speed and adherence for most people.
- Aggressive (≈25%): Short sprints only; plan diet breaks.
Target calories = TDEE × (1 − chosen deficit). Keep your weekly average below maintenance; day‑to‑day can flex for lifestyle.
Make choosing meals effortless
The Calorie Deficit Deck (52 cards) helps you build plates that fit your target: pick a veggie, pick a protein, pick a grain. Simple.
Worked Example
Let’s say Alex (35, 5′9″, 180 lb, lightly active) wants steady fat loss.
- BMR (Mifflin–St Jeor, metric): weight 81.6 kg, height 175 cm → Men formula → ~1,770 kcal.
- TDEE: 1,731 × 1.375 (lightly active) → ~2,380 kcal.
- Moderate 20% deficit: 2,435 × 0.80 → ~1,880 kcal/day target.
Numbers are estimates—track your 7‑day weight average for 2–4 weeks and adjust ±100–150 kcal if needed.
"Pick one from each" idea
Veggie
Protein
Grain
Setting Macros (that actually help adherence)
- Protein: ~0.7–1.0 g per lb of goal bodyweight (or 1.6–2.2 g/kg). Prioritize lean sources to protect muscle and improve satiety.
- Fat: Allocate ~20–35% of calories (don’t go too low—hormones & flavor matter).
- Carbs: Fill the remainder based on preference and training.
- Fiber: Aim for 25–35 g/day from fruits, veg, legumes, and whole grains.
Fast track: use our TDEE & Macro Calculator to auto‑split these numbers.
How to Track (without going crazy)
- Pre‑log your day when possible—plan, then eat.
- Weigh portions for a couple weeks to recalibrate your eye.
- Measure the trend: weigh daily, average weekly; also track waist and photos.
- Audit weekends: small “untracked” bites can erase a week’s deficit.
Common Mistakes to Avoid
- Overestimating activity and underestimating intake.
- Chasing huge deficits that trigger binges and burnout.
- Ignoring protein and fiber—your natural hunger brakes.
- Letting one off‑plan meal become a weekend free‑for‑all.
Plateaus, Refeeds & Diet Breaks
Stalled for 2+ weeks? First confirm adherence (food scale, alcohol, sauces, weekends). If still stuck:
- Increase steps by 2–3k/day or trim 100–150 kcal from your daily target.
- Consider a planned refeed day (back to maintenance) or a diet break (maintenance for 1–2 weeks) to restore compliance.
- Prioritize resistance training 2–4×/week to preserve muscle.
Plan smarter with the Calorie Deficit Deck
52 illustrated cards grouped by veggies, proteins, grains, fruits and fats—each with volume per 100 calories, protein & fiber stats, and a simple rating. Great for visual meal planning, grocery lists, and staying on track when life gets busy.
- See how much you can eat for 100 calories (volume matters)
- Compare protein and fiber at a glance for better satiety
- Build plates by mixing one from each category
Next Step: Get Your Numbers in 60 Seconds
Use the free TDEE & Calorie Deficit Calculator, then grab the eBook for meal templates and the 52‑card Food Deck to make sticking to the plan easy.
Buy the eBookFrequently Asked Questions
How fast should I lose weight?
About 0.5–1.0% of bodyweight per week works well for most people. Larger bodies may safely lose faster early on; very lean folks should go slower.
Do I have to track forever?
No. Track until you’ve built portion awareness and habits. Many people transition to a “calorie budget + protein + portion visuals” approach for maintenance.
Will a small deficit put me in “starvation mode”?
True metabolic shutdown is not a concern in normal dieting. What most people feel is hunger & water weight changes. Keep protein high, lift, sleep, and adjust gradually.
Should I eat back exercise calories?
If your TDEE already includes typical activity, you usually don’t need to. For unusually long or intense sessions, eat a portion back based on performance and hunger.