Free Health & Wellness Calculators

18 evidence-based tools for fitness, nutrition, sleep and family health

Health guidance is full of formulas — BMI percentiles for children, blood-pressure categories, macronutrient splits, mg/kg dosing references, sleep-cycle timing — that are published in clinical literature but annoying to compute by hand. These tools implement the standard published versions: CDC growth-chart methodology for kids' BMI, AHA blood-pressure categories, Mifflin-St Jeor-based macro math, 90-minute sleep-cycle arithmetic.

Two honest caveats, stated up front. First, these are educational references, not medical advice — they're the same formulas your clinician uses for orientation, but a formula can't examine you. Second, precisely because health data is sensitive, every tool runs entirely in your browser: no measurement, symptom or date you enter is ever transmitted anywhere.

All Health Tools at a Glance

What Each Tool Does

Every tool below opens instantly, needs no account, and processes your data locally in your browser. Here is what each one is for:

BMI for Kids

Child BMI scored the correct way — against CDC age-and-sex percentiles, not adult cutoffs — with honest guidance on what the number can and can't say. Open the BMI for Kids →

Blood Pressure

Any reading classified against the AHA's five categories, the measurement technique that makes home numbers valid, and the thresholds that mean 'today, not someday.' Open the Blood Pressure →

Sleep Cycles

Bedtimes back-computed from your alarm through 90-minute cycles — wake between cycles instead of mid-slow-wave, and mornings change. Open the Sleep Cycles →

Running Pace

Solve any of pace/time/distance, predict race times across distances with Riegel's formula, and get the split table for race day. Open the Running Pace →

Water Intake

Weight- and activity-based fluid targets in ounces, liters and bottles — with the myths (8 glasses, coffee dehydrates) retired by the actual evidence. Open the Water Intake →

Macros

TDEE → goal calories → gram targets, protein anchored first the way the evidence says — with per-meal translation and food examples. Open the Macros →

Cholesterol Ratio

The lipid panel translated: total/HDL and triglyceride/HDL ratios computed and graded, LDL targets by risk, and the levers that move each line. Open the Cholesterol Ratio →

Stress Score

Ten questions across the Maslach dimensions — exhaustion, cynicism, efficacy — scored into honest bands with the interventions that have evidence. Open the Stress Score →

Vitamin D Sun

Synthesis minutes by skin tone, season and latitude — with the honest winter verdict (above ~37°N, the sun clocks out) and the supplement math. Open the Vitamin D Sun →

Pollen Guide

The tree/grass/ragweed calendar by US region, your exposure score from symptoms and season, and the start-meds-two-weeks-early strategy. Open the Pollen Guide →

Dosage Reference

Weight-based OTC dosing (the accurate method) for children's acetaminophen and ibuprofen in mL — with intervals, maximums and the never-cross lines. Open the Dosage Reference →

Cycle Tracker

Three cycles predicted ahead — periods, ovulation, fertile window — plus the phase map and when irregularity deserves a doctor. Open the Cycle Tracker →

Pregnancy Gain

Your IOM range from pre-pregnancy BMI, the week-specific band you should be in, and the anatomy of where pregnancy weight actually goes. Open the Pregnancy Gain →

Diaper Usage

Changes per day by age, monthly and first-year totals by brand tier, the cloth-vs-disposable ledger, and what to actually stockpile. Open the Diaper Usage →

Milestones

The CDC 'most children do' milestones by age band across all four domains — with the act-early flags and the honest range-not-race framing. Open the Milestones →

Fall Risk

The STEADI screening questions scored into risk bands, the 12-second timed test, and the interventions with real trial evidence. Open the Fall Risk →

Hearing Age

Your noise-exposure history converted to an estimated 'hearing age,' the decibel-dose table that governs it all, and the checkup thresholds. Open the Hearing Age →

Skin Cancer Risk

Risk factors scored honestly — skin type, burns, tanning beds, family history — with the ABCDE checklist and who needs annual dermatology. Open the Skin Cancer Risk →

How to Choose the Right Tool

Fitness and nutrition: the Macro, Water Intake and Running Pace calculators cover training basics. Sleep, use the Sleep Cycle calculator to pick a wake-friendly bedtime. Heart health, the Blood Pressure and Cholesterol Ratio tools classify readings against published categories. Parents get BMI for Kids, Pregnancy Weight Gain, Newborn Diaper and Toddler Milestone references; for older adults, the Fall Risk and Hearing Age assessments flag when a professional evaluation is worth scheduling. The Cycle Tracker handles period and fertility-window prediction privately.

Frequently Asked Questions

Are these tools medically reliable?

They implement standard published formulas and categories (CDC, AHA, ACOG, WHO sources are cited on each tool). They're reliable as references — but they are not a diagnosis and don't replace a clinician.

Is my health data private?

Completely. Weights, dates, readings and answers are processed locally in your browser and never uploaded, logged or stored.

Why do results sometimes differ from other sites?

Usually because a different formula version is used (there are several body-fat and hydration formulas, for example). WiserWork tools name the formula they use so you can compare like with like.

Can I use these for my children?

The pediatric tools (BMI for Kids, dosage reference, milestones) use age-specific published data. For any medication or health concern, always confirm with your pediatrician.

Explore More WiserWork Categories

WiserWork offers 295 free browser-based tools across 22 categories — all private, all free, no sign-up required.