Free Nutrition & Cooking Calculators: Plan Your Diet Without Paying a Coach (2026)

You don’t need a paid coach or a subscription app just to work out how much to eat. The maths behind a diet plan — calories, macros, hydration, portion sizes — is well understood, and you can get every number you need from a handful of free calculators.

We built a full set of them, free and with no sign-up, at swoodie.app/tools. This guide walks through them in the order you’d actually use them — from “how many calories should I eat?” all the way to “how do I halve this recipe?”

Step 1 — Find your calorie target

Everything starts with energy balance. First find your maintenance level, then adjust it for your goal.

• TDEE Calculator — your Total Daily Energy Expenditure (maintenance calories) and resting metabolism (BMR), using the Mifflin-St Jeor equation. This is the number everything else builds on.
• Calorie Deficit Calculator — pick a pace and it gives you the daily calories to lose weight, plus a realistic estimate of how long it’ll take to reach your goal.
• BMI Calculator — a quick sense-check of where your weight sits and a healthy range for your height. (It’s a blunt tool — it can’t tell muscle from fat — so treat it as a starting point, not a verdict.)

Step 2 — Dial in your macros

Calories decide whether you lose or gain; macros decide how good you feel and whether you keep muscle while you do it.

• Protein Intake Calculator — protein is the macro most people under-eat. This sets a daily target (in grams) based on your weight and goal.
• Keto Macro Calculator — eating low-carb? This splits your calories into net carbs, protein, and fat for a keto approach.

Step 3 — Account for exercise and hydration

• Calories Burned Calculator — estimate what you burn across 30+ activities. Useful for context, though remember you can’t reliably out-train a big calorie surplus.
• Water Intake Calculator — a daily water target based on your weight, activity, and climate.

Step 4 — Time your eating (optional)

If you fast, the hard part is remembering when your window opens and closes.

• Intermittent Fasting Calculator — enter when you stop eating and it shows exactly when you can eat again for 16:8, 18:6, OMAD, and custom protocols. More on the approach in intermittent fasting with Swoodie.

Step 5 — Actually cook the food

The numbers are useless if the recipe fights you. These remove the friction in the kitchen:

• Cooking Measurement Converter — cups to grams, ounces, millilitres and back, with ingredient density baked in (a cup of flour and a cup of sugar do not weigh the same).
• Oven Temperature Converter — °C, °F, gas mark, and fan-oven temperatures in one place.
• Recipe Scaler — halve, double, or resize any recipe to the number of servings you actually need.
• Safe Cooking Temperatures — the safe internal temperature for chicken, beef, pork, and fish in °F and °C, so you cook it through without drying it out.

From numbers to meals

Free calculators give you the targets; the daily grind is hitting them. That is the part Swoodie automates — it works out your TDEE and macros from your profile, then logs every meal against them when you scan a plate or a barcode, generates recipes that fit your remaining budget, and builds a weekly plan with a shopping list. If weight loss is the goal, the weight-loss guide ties the whole workflow together.

Two related reads to go further: our guide to free 7-day diet meal plans (keto, high-protein, paleo and more), and — if you pair the calculators with a step tracker — whether your steps count as calories.

Bookmark the full set at swoodie.app/tools — all free, no account, no ads.

These tools give general estimates for healthy adults and are not medical advice. For therapeutic diets or medical conditions, consult a registered dietitian or doctor.