Calculators

Seven calculators that turn your numbers into a plan

Each tool runs in your browser, so your inputs stay on your device. Move a slider or type a stat and the answer updates as you watch. Pick one below, or scroll the full set grouped by sleep, body, and nutrition.

Sleep

How much sleep debt are you carrying?

Set your average night and the amount you need. The tool turns the nightly gap into a weekly number, because the shortfall compounds across the week.

Sleep

Sleep Debt Calculator

12.6
hours of weekly sleep debt
Sleep

What is left in your system at bedtime?

Caffeine clears with a half-life near five hours. Enter your dose and timing to see how much is still circulating when you try to sleep.

Caffeine

Caffeine at Bedtime Calculator

53
mg still in your system at bedtime (7.5 h later)
Based on a 5-hour half-life.
Body

A BMI number with its limits attached

BMI screens populations. The scale below shows where you land, and the note explains why the number alone never tells the whole story.

Body

BMI With Context

24.3
BMI, Normal range
1518.5253040

A normal-range weight for 178 cm lands near 58.6 to 78.9 kg (129 to 174 lb).

BMI screens populations. It cannot separate muscle from fat, so a lean lifter can read high while carrying little body fat. Use it as one signal next to waist measurement and how you feel, not a verdict.

Body

Daily targets you can set right now

Hydration

Daily Water Target

3.08
liters of water per day (13 cups)
Food and other drinks count toward this. Thirst and pale urine stay the best daily check.

Strength

One-Rep-Max Estimator

263
estimated one-rep max (lb), Epley formula
Training loads from this max
Target repsSuggested load
1 rep263 lb
2 reps255 lb
3 reps247 lb
5 reps232 lb
8 reps213 lb
10 reps202 lb
12 reps192 lb
Nutrition

Set a daily protein target

Protein need scales with bodyweight and how hard you train. Pick your weight and activity to read a gram-per-day goal.

Protein Target Calculator

123
grams of protein per day
Nutrition

Estimate the calories you burn in a day

The Mifflin-St Jeor equation finds your resting rate, then an activity factor scales it to your total daily burn.

Calorie / TDEE Calculator

2,695
calories per day to maintain weight
Resting metabolic rate: 1,739 kcal.
Evidence library

Compounds behind these numbers

The goals these calculators point at have well-studied compounds attached. Tap through for mechanism, dose, and sources.

Frequently asked questions
How accurate are these calculators?
They give you a solid starting estimate, not a clinical measurement. Each one uses a published formula or a well-supported rule of thumb. Real bodies vary, so treat the output as a baseline you adjust from once you track how you respond.
Does my data leave the browser?
No. Every calculation runs on your device in JavaScript. Nothing you type is sent to a server or stored anywhere.
How is the one-rep max estimated?
The tool uses the Epley formula: estimated 1RM equals the weight lifted times one plus reps over thirty. It stays close for sets up to about ten reps, then drifts high, so a heavier test set gives a tighter number.
Why does BMI come with so many caveats?
BMI is a screening number built for populations, not individuals. It divides weight by height squared and cannot separate muscle from fat. A lean, muscular person can read overweight while carrying little body fat, so pair it with a waist measurement and your own goals.
How much water do I actually need?
The tool starts from roughly thirty-five milliliters per kilogram of bodyweight and adds for activity and heat. Food and other drinks count toward the total. Thirst and pale-yellow urine remain the most reliable daily check.
How is my protein target calculated?
Bodyweight in kilograms times an activity factor: about 1.2 sedentary, 1.6 active or lifting, and 2.0 for athletes. Pounds convert to kilograms first. The result lands in the range research links with muscle maintenance and growth.
What is TDEE?
Total daily energy expenditure, the calories you burn in a day. The tool finds your resting rate with the Mifflin-St Jeor equation, then multiplies by an activity factor for a maintenance estimate.