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Macro CalculatorDaily Protein, Carbs, Fat, Fiber & Water From Your Body Weight

Enter one number and get your full daily nutrition target instantly — including the fiber and water almost every other macro calculator leaves out.

Your details

30 kg200 kg
Your goal
Advanced coefficients

Your daily targets

Calories

1,820

kcal / day

26.0 kcal per kg

Protein

140

grams / day

31% of calories

Carbs

179

grams / day

39% of calories

Fat

61

grams / day

30% of calories

Fiber

25

grams / day

Counts inside carbs

Water

2.3

liters / day

33.3 ml per kg

Where your calories come from

1,820kcal
  • Protein140 g · 31%
  • Carbs179 g · 39%
  • Fat61 g · 30%

Per meal

Calories

607

kcal

Protein

47

g

Carbs

60

g

Fat

20

g

Spread across 3 meals a day. Aim for roughly 8 g of fiber and 0.8 L of water per meal to stay on track without thinking about it.

Show the math
TargetCalculationResultWhere the rule comes from
Daily calories70.0 kg × 26.0 kcal/kg1,820 kcalThe 25–30 kcal per kg rule of thumb clinical dietitians use for a quick energy estimate.
Protein70.0 kg × 2.0 g/kg140 gSits in the 1.6–2.2 g/kg range repeatedly shown to support muscle retention and growth.
Fat1,820 kcal × 30% ÷ 9 kcal/g61 g30% of calories from fat is the midpoint of the 20–35% acceptable range for adults.
Fiber1,820 kcal ÷ 1,000 × 14 g25 gThe Institute of Medicine adequate intake of 14 g of fiber per 1,000 calories.
Carbohydrates(1,820 − 560 protein kcal − 546 fat kcal) ÷ 4 kcal/g179 gCarbs fill whatever energy is left once protein and fat are set — that is what makes the split add up.
Water70.0 kg × 33.3 ml/kg2.33 LRoughly 33 ml per kg, the middle of the 30–40 ml/kg hydration guideline for healthy adults.

Disclaimer: These are rough estimates, not medical advice. They come from general population averages and cannot account for your medical history, medication, body composition or training load. Talk to a doctor or registered dietitian before changing your diet — especially if you are pregnant or breastfeeding, under 18, managing a chronic condition such as diabetes or kidney disease, or have any history of disordered eating.

What Is a Macro Calculator?

A macro calculator turns a single number — your body weight — into the four numbers that actually decide what you eat each day: how many calories to aim for, and how those calories split across protein, carbohydrates and fat. "Macros" is short for macronutrients, the three nutrients your body needs in gram-scale amounts. Protein and carbohydrates carry 4 calories per gram, fat carries 9, and every diet plan you have ever seen is just a different way of dividing those three.

Most calculators stop at those three. This one adds the two targets that quietly decide whether a plan is liveable: fiber and water. Fiber has no calories but drives satiety, digestion and cholesterol, and almost no one hits the recommended intake. Water is the single easiest variable to get wrong when you increase protein. Leaving both out is why so many macro plans technically add up and still feel awful by day four.

The method here is deliberately weight-based rather than a long questionnaire. Multi-step calculators ask for age, height, sex, body-fat percentage and an activity level, then feed it all through the Mifflin-St Jeor equation — which is excellent, but the activity multiplier you self-select swings the answer by 600 calories, so the extra precision is often an illusion. Anchoring to body weight gives you a defensible starting point in one input, and every coefficient is exposed so you can tune it as you learn how your body responds.

How to Use This Macro Calculator

  1. 1Enter your body weightType your weight or drag the slider. Switch between kilograms and pounds with the toggle — results recalculate as you type, with no Calculate button and no email wall.
  2. 2Pick your goalLose fat, maintain, or build muscle. Only your calorie target moves (22, 26 or 30 kcal per kg); protein stays at 2 g per kg in every mode, because that is what protects muscle in a deficit and builds it in a surplus.
  3. 3Read your six targetsCalories, protein, carbs, fat, fiber and water appear instantly, with a ring chart showing how your calories split. Open "Show the math" to see the exact arithmetic and the guideline behind every coefficient.
  4. 4Split them across your mealsChoose 2 to 6 meals a day to see per-meal grams — the number you actually cook to. Then copy, download or print your plan, or save a link that restores your setup on any device.

Why Use This Macro Calculator Instead of the Others

No email, no account, no upsell

The most popular macro calculators hold your results hostage behind an email form and follow up with a coaching pitch. Your numbers appear here the moment you type — there is nothing to sign up for and nothing to unsubscribe from.

Your health data never leaves the device

Body weight and diet goals are sensitive. Every calculation runs in JavaScript inside this tab, so nothing is posted, logged or profiled. Open your browser's Network panel and watch: there is no request to block.

Fiber and water included

Virtually every competing calculator returns three numbers. You get six. Fiber is set from the 14 g per 1,000 kcal adequate intake and water from the 30–40 ml per kg guideline, so your plan is complete rather than half-finished.

Every coefficient is editable

Disagree with 26 kcal per kg or want 2.4 g of protein? Open the advanced panel and change the calories per kg, protein per kg, fat percentage, fiber density and water rate. Most calculators hard-code these and never tell you what they used.

It shows its work

A "Show the math" panel prints the substituted arithmetic for all six numbers plus the guideline each rule comes from. You can verify the result on paper — no black box, no proprietary formula.

Per-meal breakdown built in

Daily totals are hard to cook to. Divide your targets across 2 to 6 meals and get the grams per plate, which is the number you actually use when portioning chicken, rice and oil.

Take the results with you

Copy a formatted summary, download it as a text file, print a clean sheet for the fridge, or generate a shareable link that rebuilds your exact setup. No calculator that emails you a PDF is faster than this.

Instant, offline and ad-light

No server round trip means no spinner and no queue. Once the page has loaded it keeps working with the Wi-Fi off, on a phone, a tablet or a locked-down work laptop.

What Each Number Actually Does

Six numbers, six jobs. This is what each target is for, the rule the calculator uses by default, and what to keep in mind when you adjust it.

NutrientDefault ruleWhat it doesWorth knowing
Calories26 kcal per kgThe total energy budget. Sets the direction of your weight.Adjust to 22 to lose or 30 to gain. Change it slowly — a swing of more than 20% at once usually backfires.
Protein2 g per kgRepairs and builds muscle, and is the most filling macro per calorie.Held constant across all three goals. Spread it across meals rather than eating it all at dinner.
CarbohydratesWhatever calories remainYour main training fuel and the fastest lever for energy in the gym.Calculated last so the three macros always add up to your calorie target exactly.
Fat30% of caloriesHormone production, vitamin absorption, joint and skin health.Going below roughly 20% of calories for long stretches tends to cause problems. This sits safely above that.
Fiber14 g per 1,000 kcalSatiety, digestion, blood sugar control and cholesterol.Counts inside your carb total — it is not extra. Increase it gradually and drink the water target alongside it.
Water33 ml per kgDigestion, performance, temperature control and appetite regulation.Food and coffee count toward it. Add roughly 500–1,000 ml on hard training days or in the heat.

Common Use Cases for a Daily Macro Calculator

  • Starting a cutSet the goal to Lose fat for roughly 22 kcal per kg — a moderate deficit that keeps protein high so the weight you drop is fat rather than muscle.
  • Lean bulkingBuild muscle mode uses about 30 kcal per kg: enough of a surplus to add tissue without the fat gain that comes from eating with no target at all.
  • Setting up MyFitnessPal or CronometerTracking apps ask for gram goals before they are useful. Get all four numbers here in seconds and paste them into your app's custom goal screen.
  • Meal prep on SundayUse the per-meal split to portion a week of containers so every meal lands on target instead of eyeballing the totals and hoping.
  • Coaching a clientPersonal trainers and nutrition coaches can dial in the coefficients, print the sheet, and hand a client a plan whose arithmetic is fully visible and defensible.
  • Flexible dieting and IIFYM"If it fits your macros" only works when you know the macros. This gives you the daily envelope, and the fiber target keeps the approach honest about food quality.
  • Rebuilding after a breakComing back from an injury, holiday or a long stretch off plan, weight-based targets get you to a sensible baseline without a 12-field questionnaire.
  • Hitting a hydration and fiber targetEven if you already know your calories, the fiber and water outputs fill the two gaps almost every other macro plan leaves open.

How This Compares to Other Online Macro Calculators

The best-known macro calculators — IIFYM, Precision Nutrition, Healthy Eater, calculator.net and the various app-vendor tools — all share the same architecture: a multi-step form, a server that does the arithmetic, and in several cases an email gate in front of your own results. That architecture is what creates the friction, and removing it is what makes this one different.

FeatureThis calculatorTypical online macro calculator
Email required for resultsNeverCommon (IIFYM, Precision Nutrition, Macro Friendly Food)
Where the calculation runsIn your browser tabOn their server
Inputs neededBody weight only6–12 fields, often multi-step
Fiber targetIncludedRarely shown
Water targetIncludedAlmost never shown
Editable coefficientsAll six exposedHard-coded and undisclosed
Shows the arithmeticYes, step by stepNo
Per-meal split2–6 mealsOccasionally
ExportCopy, download, print, share linkEmailed PDF at best
Works offlineYesNo
CostFree, no tierFree tier with paid coaching upsell

How Accurate Are Weight-Based Macro Estimates?

Every calorie calculator on the internet produces an estimate, including the ones with twelve input fields. The Mifflin-St Jeor equation, the most respected of them, predicts resting metabolic rate within about 10% for most people — and then a self-selected activity multiplier is applied on top, which is where the real error creeps in. Two honest people with identical bodies routinely pick multipliers that differ by 25%.

A weight-based rule such as 26 kcal per kg lands in a similar range for adults of average build, with one advantage: it has one assumption instead of three, so when reality disagrees with the number you know exactly which dial to turn. It is less reliable at the extremes — if you are very lean, very tall, very short, carrying a lot of fat mass, or training twice a day, the estimate will drift.

Treat any starting number as a hypothesis, not a prescription. Eat to it for two full weeks while weighing yourself under the same conditions each morning, then compare the fortnight's average against the one before. Losing faster than about 1% of body weight per week, or gaining faster than about 0.5%, means adjust calories by 10% and repeat. That feedback loop beats any formula, which is exactly why every coefficient in this calculator is editable.

Frequently Asked Questions About the Macro Calculator

How do I calculate my macros?

Start with calories, then set protein and fat, and let carbs absorb the remainder. This calculator does it as: body weight in kg × 26 = daily calories; body weight × 2 = protein in grams; 30% of calories ÷ 9 = fat in grams; calories × 0.014 = fiber in grams; and finally (calories − protein calories − fat calories) ÷ 4 = carbs in grams. Water is body weight ÷ 30 in liters. Enter your weight above and all six appear at once.

Why does this only ask for my body weight?

Because body weight is the input that carries most of the signal. Longer calculators add age, height, sex and an activity multiplier, but that multiplier is self-reported and can swing the result by hundreds of calories, so the added precision is often false precision. If you want to account for those factors, open the advanced panel and adjust the calories per kg directly — that is the same dial the extra questions were turning.

Is my weight and health data sent anywhere?

No. There is no backend involved in the calculation. Everything runs in JavaScript inside your browser tab, nothing is transmitted, stored on a server or logged, and your saved settings live only in your own browser's local storage. You can confirm it by opening the Network panel, or by switching off your connection — the calculator keeps working.

How much protein should I eat per day?

The default here is 2 g per kg of body weight, which sits in the well-supported 1.6–2.2 g/kg range for anyone doing resistance training or trying to hold muscle while losing fat. Sedentary adults with no body-composition goal can do fine at 1.2–1.6 g/kg; people in an aggressive deficit sometimes push toward 2.4 g/kg. All of those are a single edit in the advanced panel.

What is the best macro split for weight loss?

There is no single best ratio — total calories decide whether you lose weight, and adherence decides whether you keep going. What matters is holding protein high enough to protect muscle and fat high enough for hormone health, then letting carbs fill the rest. That is what the defaults do: choose the Lose fat goal, keep protein at 2 g/kg and fat at 30%, and carbs adjust automatically to the smaller calorie budget.

Should I count fiber toward my carbohydrate total?

Yes. Fiber is a carbohydrate, so the fiber target sits inside your carb number rather than on top of it. Hitting roughly 14 g per 1,000 calories from vegetables, fruit, legumes and whole grains is one of the highest-return changes most people can make, and it also keeps you full on fewer calories. Increase it gradually over a week or two and drink your water target alongside it.

Do I need to eat exactly these numbers every day?

No. Aim to land within roughly 10% of your calorie and protein targets, and treat carbs and fat as a weekly average rather than a daily test. Consistency across a week matters far more than precision on any single day, and chasing exact grams is the fastest route to giving up on tracking entirely.

Can I use this calculator in pounds?

Yes — the unit toggle switches weight between kilograms and pounds, and water between liters and US fluid ounces. Everything is converted internally to metric for the calculation, so you get identical results either way.

Important Health Disclaimer

The numbers this calculator produces are rough estimates generated from general population averages. They are not medical advice, not a diagnosis, and not a personalised nutrition prescription. No calculator can account for your medical history, medications, body composition, genetics, training load or lab work.

Speak to a doctor or a registered dietitian before changing your diet if you are pregnant or breastfeeding, under 18, over 65, managing diabetes, kidney or liver disease, heart conditions, thyroid disorders or any chronic illness, taking medication affected by diet, recovering from surgery or injury, or have any history of disordered eating. Very low calorie intakes in particular should only be undertaken with medical supervision.

If a target here looks extreme for your situation, trust that instinct over the arithmetic and get professional guidance. Stop and seek help if a plan leaves you dizzy, exhausted, unable to concentrate, or anxious about food.

Privacy note: this calculator has no backend. Your body weight, goal and coefficients are multiplied together in JavaScript inside this tab, saved only to your own browser's local storage, and never transmitted. There is no upload to block, no account attached to your health data, and no retention policy to trust — which is why the whole thing keeps working with your connection switched off.

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Works offline

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Verify it yourself

Open your browser's DevTools → Network tab. You'll see zero requests carrying your data.