Calculators

Free online tools for weather, statistics, dates, and demographics.

Weather

3 tools

Wind chill, heat index, dew point, and other meteorological conversions.

Wind ChillHeat IndexDew Point

Statistics

4 tools

Percentages, averages, standard deviation, and statistical analysis tools.

PercentageMean, Median & ModeStandard Deviation +1

Date & Time

2 tools

Age calculations, date differences, and time-based computations.

AgeDays Between Dates

Demographics

1 tools

Population projections, growth rate modeling, and demographic analysis.

Population Growth

Weather

Weather 13.12 + 0.6215T − 11.37V⁰·¹⁶

Wind Chill Calculator

Calculate the perceived temperature based on air temperature and wind speed.

WindTemperature
Weather −42.379 + 2.049T + 10.14H

Heat Index Calculator

Calculate the perceived temperature based on air temperature and relative humidity.

HeatHumidity
Weather (237.3 × α) / (17.27 − α)

Dew Point Calculator

Calculate the dew point temperature from air temperature and relative humidity.

MoistureHumidity

Statistics

Statistics (part / whole) × 100

Percentage Calculator

Calculate percentages: what is X% of Y, X is what % of Y, and percentage change.

PercentagesRatios
Statistics Σxᵢ / n

Mean, Median & Mode Calculator

Calculate mean, median, mode, standard deviation, and variance for a set of numbers.

AveragesDistribution
Statistics √(Σ(xᵢ − x̄)² / n)

Standard Deviation Calculator

Calculate the standard deviation and variance of a dataset.

VarianceSpread
Statistics ((new − old) / old) × 100

Percentage Change Calculator

Calculate the percentage increase or decrease between two values.

GrowthChange

Date & Time

Date & Time

Age Calculator

Calculate exact age from date of birth in years, months, and days.

BirthdayYears
Date & Time

Days Between Dates Calculator

Calculate the number of days between two dates.

DurationInterval

Demographics

Demographics P₀ × (1 + r)ᵗ

Population Growth Calculator

Project future population based on initial population, growth rate, and time period.

ProjectionGrowth Rate

Frequently Asked Questions

Free online calculators for wind chill, heat index, percentage, standard deviation, BMI, age, and more. Each shows step-by-step formulas and worked examples.

Each calculator uses the standard published formula for its domain (e.g. NWS wind chill formula, Rothfusz heat index regression). Results update instantly as you type.

Yes, all calculators are free to use with no registration or download required.