Look up any HTTP status code — 200 to 511 — with plain-English explanations, common causes, and what to do next.

Calculate percentages, percentage increase, decrease, difference, and reverse percentages instantly with step-by-step formulas.

Calculate your exact age in years, months, weeks, days, hours, and minutes. Includes next birthday countdown, birth info, zodiac signs, and milestone tracker.

Convert Unix timestamps to human-readable dates and vice versa. Live clock, timezone conversions, and common duration cheat sheet.

Decode JWT tokens to view header, payload, and signature with expiry countdown and validation.

Generate and validate UUIDs (v1, v4, v5) with formatting options and batch generation.

Validate cron expressions with human-readable explanations and next execution times.

Count words, characters, and sentences with reading time estimation and live updates.

Calculate your Body Mass Index using your height and weight. Understand your BMI category and healthy weight range with this simple calculator.

Calculate your Basal Metabolic Rate using the Mifflin-St Jeor equation. Estimate your daily calorie needs based on activity level.

Convert between length, weight, area, volume, temperature, speed, time, digital storage, energy, and pressure units instantly.