Macro Calculator for Weight Loss

Use the Macro Calculator for Weight Loss

Apply a calorie deficit and see balanced cutting macros to preserve muscle while you lose fat.

How to Use Macro Calculator for Weight Loss

1. Step 1: Select units & sex

   Choose Metric or US units and select your sex for accurate BMR.

2. Step 2: Enter age, height, weight

   Add your details. Optionally enter body‑fat% to use the Katch–McArdle method.

3. Step 3: Pick activity level

   Select the option that best matches your typical week to estimate TDEE.

4. Step 4: Set your goal

   Use a deficit% (10–25% is common) or a weekly loss target to create your calorie goal.

5. Step 5: Choose protein & fat rules

   Set protein (g/kg or g/lb LBM) and fat (g/kg or % calories). Carbs auto‑fill the remainder.

6. Step 6: Review macros & adjust

   Copy your macros. Tweak settings until the plan feels sustainable on training and rest days.

Key Features

• Deficit presets
• Weekly loss estimate
• Protein safeguards
• Refeed options

Understanding Results

Formula

Your plan begins with basal metabolic rate (BMR) and total daily energy expenditure (TDEE). If you provide body‑fat%, we use the Katch–McArdle equation (BMR = 370 + 21.6 × lean mass in kg). Without body‑fat%, we use Mifflin–St Jeor (BMR = 10 × weight[kg] + 6.25 × height[cm] − 5 × age + s, where s = 5 for men and −161 for women). We estimate TDEE by multiplying BMR by an activity factor. Target calories are then set by either a percent deficit (e.g., 15%) or a weekly‑loss target converted to a daily deficit (≈7,700 kcal per kg, ≈3,500 kcal per pound).

Reference Ranges & Interpretation

Sustainable fat‑loss plans typically use a 10–25% calorie deficit. Protein commonly sits around 1.6–2.2 g/kg body weight (or ~0.7–1.0 g/lb lean mass) to help preserve muscle. Fat should remain above ~0.4 g/kg body weight to support hormones; carbohydrates fill the remainder. Many people feel and perform best by keeping more carbs on training days. A simple fiber target is ~14 g per 1,000 kcal.

Assumptions & Limitations

All estimations have error. Changes in steps, training volume, sleep, and hydration can shift daily weight independently of fat. If progress stalls for several weeks despite consistent tracking, reduce calories slightly, increase daily movement, or take a short maintenance break before resuming. This tool provides information, not medical advice—consult a clinician if you have a condition or take medications.

Complete Guide: Macro Calculator for Weight Loss

This macro calculator for weight loss applies a deficit and recommends protein, carbs, and fat to preserve muscle while cutting. Simple, clear, and effective.

Why macros matter for fat loss

Calories determine the direction of weight change, but macronutrients—protein, carbohydrates, and fat—shape how you feel, perform, and retain muscle while dieting. During a calorie deficit, sufficient protein helps preserve lean mass and supports satiety, carbs can fuel training and daily activity, and fat supports hormones and fat‑soluble nutrient absorption. A well‑constructed macro plan lets you lose fat while keeping energy, strength, and appetite in check.

Our macro calculator for weight loss ties these pieces together. It estimates your daily energy needs, applies a sensible deficit, and sets protein and fat to safe, practical levels—then fills the rest with carbs. The result is a complete, day‑to‑day plan you can start using immediately.

Think of macros as the dials you can turn without breaking the machine. Protein keeps the frame intact, carbs let you press the gas, and fat keeps the engine lubricated. Many people fail a diet not because the calorie number is wrong, but because the meal pattern is uncomfortable. Stable macros reduce that friction.

How this macro calculator for weight loss works

Behind the scenes, the tool estimates your basal metabolic rate (BMR) using either the Katch–McArdle equation (when you provide body‑fat%) or the Mifflin–St Jeor equation (when body‑fat% is unknown). BMR is then multiplied by an activity factor to estimate total daily energy expenditure (TDEE). From there, you choose either a percent deficit or a weekly weight‑loss target—both route to a daily calorie target.

Next, you set protein using a simple rule of thumb: either grams per kilogram of body weight or grams per pound of lean body mass when you know body‑fat%. Fat is set either as grams per kilogram or as a percentage of calories. The remaining calories go to carbohydrates. Finally, the calculator reports grams per day for each macro, plus the overall macro split and a helpful daily fiber target.

You can revisit the inputs weekly. As you lose weight, your TDEE usually trends down a bit; small adjustments keep your plan realistic. Notice that your scale weight can fluctuate daily from water, glycogen, and gut content. Focus on the rolling average, not any single morning.

For reference, the Mifflin–St Jeor paper is indexed on PubMed, and the lean‑mass method (Katch–McArdle) is a common field equation. You can skim the abstract for Mifflin–St Jeor on PubMed. For protein ranges during energy restriction, see a meta‑analysis on PubMed (e.g., Morton et al.). These external sources are descriptive, not prescriptive, and this tool does not offer medical advice.

Picking your deficit: percent vs weekly target

Both options lead to the same place—a daily calorie target—but they feel different when you plan your week. A percent deficit (for example, 15%) automatically scales with your TDEE. Many people find 10–25% sustainable for a slow, steady cut. A weekly loss target (for example, 0.45 kg/1.0 lb per week) converts to a daily calorie deficit (≈7,700 kcal per kg, ≈3,500 kcal per pound) and can be easier to relate to the scale.

If you are new to tracking food, start with a mild deficit (10–15%). You’ll get feedback quickly without crushing hunger. If you are smaller or already lean, favor a smaller deficit to protect training quality. If you have a lot of weight to lose, you may tolerate the higher end of the range initially—then taper the deficit as progress slows.

Weekly loss targets are appealing, but remember that the scale includes more than fat. If your strength training volume increases or if you reintroduce carbohydrates, water weight can mask fat loss. Use waist measurements and progress photos alongside the scale for a complete picture.

Protein: how much, why, and how to set it

Protein is the anchor macro while dieting. Higher protein helps preserve lean mass, improves satiety, and supports recovery. Practical cutting ranges are roughly 1.6–2.2 g/kg of body weight per day, or ~0.7–1.0 g per pound of lean mass when you know body‑fat%. Distribute protein across 3–4 meals to make each meal satisfying and to keep hunger predictable.

In the calculator, choose whether you’d like to base protein on body weight (g/kg) or on lean mass (g/lb LBM). If you have a reliable body‑fat% estimate, the lean‑mass method is often a touch more precise for smaller framed or higher body‑fat individuals. Otherwise, g/kg body weight is simple and works well. The app pulls the rest of your plan around this protein choice.

Practical tip: don’t chase perfection—chase consistency. If your daily target is 140 g of protein, hitting 130–150 g is fine. Build repeatable meals you like (for example, Greek yogurt + berries, eggs + toast, chicken + rice + vegetables) and rotate sauces for variety without changing the macro backbone.

Carbs vs fat: choosing the split you can stick to

After protein, there is plenty of flexibility. Some prefer higher carbs to support training and daily steps; others feel better with a bit more fat for slower‑digesting meals. A safe minimum for fat intake is about 0.4 g/kg body weight per day. Above that, choose what helps you stay consistent. The calculator lets you set fat as g/kg or as a percent of calories; carbs then fill the remainder.

If you’re highly active or focus on performance, keep carbs higher on training days. If you sit most of the day or prefer low‑carb foods, a modest‑carb split can be fine as long as protein and calories are in place. There is no single best macro split—there is the split you can sustain.

Fiber helps appetite control regardless of the split. A simple heuristic is ~14 g per 1,000 kcal. That usually lands around 20–35 g/day for most cutting plans. Spread fiber across meals and stay hydrated to keep digestion comfortable.

Activity level and TDEE: get the starting point right

TDEE is the backbone of your plan. Over‑ or under‑estimating activity skews everything. Use the lowest activity level that honestly reflects your typical week. Re‑estimate TDEE every few weeks as your weight and routine change.

If you want a second opinion on your calorie baseline, try our TDEE Calculator and compare results. You can also cross‑check with the Maintenance Calorie Calculator. Consistent readings within a narrow range are a good sign your inputs are solid.

On very low step counts (e.g., under 4,000 per day), your TDEE may be lower than expected. Adding a short daily walk is one of the simplest ways to protect your calorie budget without increasing hunger. Small changes in daily movement add up quickly over a week.

Refeed days and diet breaks: when and how to use them

Refeeds are planned days where you temporarily increase carbs—often keeping calories similar—to refill glycogen and provide a mental break. The calculator includes an optional refeed day suggestion: it keeps protein the same, boosts carbs by a percentage you choose, and reduces fat to maintain your target calories that day.

Diet breaks are longer (for example, a full week at maintenance). They can help adherence during long cuts. If the scale stalls for several weeks despite accurate tracking and steps, you can hold calories steady or take a short break before resuming a smaller deficit.

Not everyone needs refeeds. If you prefer routine, skip them and let your plan do the work. If you train hard or enjoy social meals on weekends, refeed days can be a structured way to enjoy more carbs without derailing progress.

Common mistakes and simple fixes

Overshooting the deficit is the most common issue. Hunger spikes, workouts suffer, and adherence drops. If your target intake is far below 1,200–1,500 kcal/day (women/men) or more than ~40% below TDEE, our tool nudges the plan to a safer level. Smaller, steadier deficits usually produce better long‑term results.

Another frequent pitfall is under‑estimating protein or skipping it at breakfast and lunch. Spread protein evenly. For guidance specific to fat loss, see the Protein Calculator for Weight Loss and the general Protein Calculator if you’re not cutting.

Weekend drift is another silent progress killer. If weekdays are on target but weekends run 800–1,200 kcal above plan, your weekly average creeps to maintenance. Planning a higher‑carb, lower‑fat refeed meal—rather than an untracked day—often keeps the week on rails.

If your weight trends down but strength collapses, increase carbs around training or slightly raise calories and reassess in 1–2 weeks. Remember: progress is the trend, not any single day.

Helpful companion calculators

Pair this macro calculator with tools that refine your inputs and expectations:

• Calorie Deficit Calculator: sanity‑check your weekly target.
• Body Fat Percentage Calculator: estimate LBM for protein by lean mass.
• BMR Calculator: compare basal estimates and see method differences.
• TDEE Calculator: confirm your daily energy needs.
• Weight Loss Calorie Calculator: translate goals into a simple daily number.

Example plans and scenarios

Here are three quick examples to show how the numbers come together. These are illustrations—not prescriptions. Use your own inputs in the calculator above to generate a personalized plan.

Example A: A 30‑year‑old woman, 167 cm and 70 kg, lightly active, chooses a 15% deficit. She sets protein at 1.8 g/kg and fat at 0.8 g/kg. Her plan lands around a moderate carb split with a fiber target in the mid‑20s (g/day). She splits protein across three meals and sets one higher‑carb day every other week to support long runs.

Example B: A 41‑year‑old man, 178 cm and 92 kg, estimates body‑fat at 24% and trains 4 days per week. He uses grams per pound of lean mass for protein (~0.8 g/lb LBM) and sets fat at ~25% of calories. Carbs fill the rest. He begins at a 12% deficit to protect training quality and adds steps on rest days to support adherence.

Example C: A petite 25‑year‑old with a desk job stalls at a large deficit and feels exhausted. She reduces the deficit to ~12%, keeps protein high, and raises carbs on training days. Two weeks later, weight trends down again and she reports better energy. Small changes often fix big problems.

In every case, the macro plan is a starting point. Use weekly averages, trend weight, and how you feel to fine‑tune the numbers. Most sustainable plans share three traits: adequate protein, a moderate deficit, and meals you enjoy.

Where to go next

Bookmark this page and re‑calculate macros as your weight, routine, or goals change. If you need a quick calorie check without macros, use the Calorie Calculator. For a compact daily target, see the Daily Calorie Calculator. When you’re ready to maintain, the Maintenance Calorie Calculator helps you transition smoothly.

Two final sanity checks: keep water intake steady and salt your food to taste. Rapid swings in water and sodium can mask fat loss on the scale. If you’re curious about hydration targets, our Water Intake Calculator provides a helpful range.

Frequently Asked Questions