Interactive calculators
Wellness Tools
Four small calculators we built for our own routines — caffeine timing, protein targets, daily fluids, and a working-backwards evening schedule. Free, no sign-up, nothing stored.
Built from published reference values
Each tool encodes the same public numbers our articles cite — caffeine half-life, protein ranges per kilogram, National Academies fluid intakes — so you can apply them to your own day instead of doing the arithmetic yourself.
Estimates, not prescriptions
Every output is a starting range for a healthy adult. Medication, pregnancy, and medical conditions move these numbers, sometimes a lot. When a tool touches one of those situations, it says so.
Caffeine cutoff calculator
Interactive tool
Caffeine cutoff calculator
Estimates your latest low-regret caffeine time from a ~5-hour average half-life. Individual clearance varies widely (roughly 1.5–9.5 hours), so treat this as a starting point, not a rule.
Last caffeine by about 5:52 PM — roughly 4.6 hours before your 10:30 PM bedtime, for ~95 mg to decay below your ~50 mg comfort level.
Simplified model for healthy adults; pregnancy, some medications, and liver conditions slow caffeine clearance substantially. General information, not medical advice.
Background and the research behind the numbers: Caffeine and sleep: timing coffee for better rest
Wind-down schedule builder
Interactive tool
Wind-down schedule builder
Enter your wake time and sleep target; get a realistic evening timeline working backwards from lights-out.
- 12:30 PMLast caffeine. Gives an average metabolism ~10 hours to clear most of a coffee.
- 7:30 PMLast large meal. Lighter evenings make it easier to fall and stay asleep.
- 9:00 PMDim the lights. Lower, warmer light signals your body clock that night has started.
- 9:45 PMStart winding down. Same short sequence nightly: tidy, prep tomorrow, then something quiet.
- 10:00 PMScreens away. Less about blue light, more about not feeding your brain one more feed.
- 10:30 PMLights out. 8 hours before your 6:30 AM alarm.
Most healthy adults need 7 or more hours of sleep per night (CDC / American Academy of Sleep Medicine). Persistent insomnia or daytime sleepiness deserves a clinician's input.
Why each step is in the schedule: Building a wind-down ritual you'll actually keep
Protein target calculator
Interactive tool
Daily protein target calculator
A body-weight-based estimate using published reference ranges — not a personalized prescription.
Daily target
84–112 g
1.2–1.6 g per kg of body weight
Per meal, across 3–4 meals
18–28 g
~0.25–0.4 g/kg per meal spreads intake where research suggests it is used best
Meta-analysis of resistance-training studies found muscle-building benefits plateau around 1.6 g/kg/day (Morton et al., 2018).
Ranges assume healthy adults. Kidney disease, pregnancy, and some medical conditions change protein needs — those call for a clinician or registered dietitian, not a calculator.
Where the ranges come from: Protein basics: a simple guide for every meal
Daily fluid estimator
Interactive tool
Daily fluid estimator
A rough beverage target built from the National Academies adequate-intake values, adjusted for activity and climate. Thirst and urine color remain better guides than any number.
Rough beverage target
2.4–2.6 L
about 10–11 cups across the day, from water, tea, coffee, milk, and other drinks combined — food typically adds another ~20% on top
Estimates for healthy adults; heart or kidney conditions, pregnancy, and some medications change fluid needs in both directions. When in doubt, ask a clinician what range is right for you.
The fuller picture on fluids: How much water you actually need for steady energy