Free Online Tools & Calculators
ToolNest brings together quick, practical calculators for health, money and everyday life. No sign-up, no downloads — just clear answers in seconds.
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Health
Body, sleep and nutrition calculators that turn simple numbers into useful daily guidance.
9 toolsFinance
Everyday money calculators for budgeting, saving, tax estimates and paying down debt.
6 toolsProductivity
Timers, trackers and planners that help you focus and keep habits on course.
2 toolsCreative
Prompt builders for AI music, image, video and writing tools — the text, never the generation.
2 toolsFun
Light, playful tools for decisions, games and passing time well.
2 toolsPopular right now
The tools people reach for most.
BMI Calculator
HealthCalculate your body mass index (BMI) from weight and height in seconds, see your WHO weight category and the healthy weight range for your height.
TDEE Calculator
HealthCalculate your total daily energy expenditure (TDEE) from BMR and activity level, and see the calories to lose, maintain or gain weight.
Tip Calculator
FinanceCalculate the tip and total on any bill and split it evenly between any number of people, with preset tip percentages from 10% to 25%.
Pomodoro Timer
ProductivityPlan focused work in 15, 25, or 50-minute blocks with short breaks, a progress ring, and a daily session count.
From the blog
The thinking behind the calculators — how each formula works, where it holds up and where it does not.
My TDEE Was Wrong for Months, And It Was My Own Fault
I picked 'moderately active' on a calculator and ate to that number for four months. Nothing happened, and the reason took me embarrassingly long to find.
Read articleBetter Sleep, Backed by Simple Math
Sleep runs on repeating cycles and a wake time you control. Working backwards from tomorrow morning takes less willpower than trying to force yourself to feel tired at night.
Read articleThe 50/30/20 Budget Rule, Explained with Real Numbers
One rule, three buckets, and a monthly income that has to stretch across all of them. Here is how the split works on a real paycheck, and what to change when it does not fit.
Read articleReady when you are
A growing library of free calculators and tools — no accounts, no spam, just answers. New tools are added regularly.
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