Free Online Tools

Your public IP address and geolocation

What your browser reveals about you

Look up DNS records for any domain — A, AAAA, MX, CNAME, TXT and more.

Inspect HTTP response headers for any URL.

Look up domain registration details — owner, registrar, expiry date.

Check SSL/TLS certificate details for any domain.

Identify vendor from MAC address OUI prefix

Look up Bluetooth Company ID (e.g. 0x004C = Apple)

Frequency ↔ wavelength for antenna design

Find mobile network operators by country

Reduce image file size without visible quality loss. Free online image compressor and photo optimizer.

Change dimensions for web or social media

Convert between PNG, JPG, WebP and more. Free online image format converter.

Trim and reframe your photos

Length, weight, volume and more

Celsius to Fahrenheit, Kelvin — instant temperature conversion calculator.

Live exchange rates worldwide. Free online currency converter and forex calculator.

HEX, RGB, HSL and CSS values

Generate QR codes for URLs, text, WiFi, and more. Free online QR code maker.

Combine multiple PDFs into one. Free online PDF merger and combiner.

Extract pages from a PDF. Free PDF splitter and page extractor.

Shrink PDFs for email or upload. Reduce PDF size online — free PDF compressor.

Encode or decode Base64 strings. Free Base64 encoder and decoder tool.

Count words, characters, sentences and paragraphs. Free online character counter.

UPPER, lower, Title, camelCase and more

Generate placeholder text instantly

Remove duplicate lines from lists

Write Markdown with live HTML preview. Toolbar shortcuts and syntax highlighting.

Beautify, validate and format JSON. Free JSON beautifier, validator, and pretty printer.

Encode or decode URL strings. Free URL encoder and decoder tool.

Generate SHA-1, SHA-256, SHA-512, and MD5 hashes online.

Generate strong, secure, random passwords on demand.

Test and debug regular expressions with real-time matching and capture groups.

Generate random UUID v4 identifiers. Bulk generate up to 100 UUIDs.

Convert Unix timestamps to dates and back. Epoch converter with timezone support.

Build and explain cron schedule expressions visually. See next execution times.

Minify HTML, CSS, and JavaScript. See size savings instantly.

Calculate CIDR notation, network address, broadcast, and host ranges.

Create beautiful CSS gradients with a visual editor. Copy CSS code.

Create CSS box shadows visually with live preview. Copy CSS code.

Convert between binary, decimal, octal and hexadecimal.

Convert between bytes, KB, MB, GB, TB and more data sizes.

Decode and inspect JSON Web Tokens. View header, payload and signature.

Compare two texts side by side and see the differences highlighted.

Calculate percentages — tip calculator, discount calculator, percentage increase and more.

Calculate your exact age from any birth date. How old am I today?

Convert numbers to Roman numerals and back. Free Roman numeral converter.

Calculate speed, distance, or time from the other two. Free SDT triangle calculator.

Add, subtract, multiply and divide fractions with step-by-step solutions.

Calculate your GPA from course grades and credit hours.

Calculate tip amount and split the bill between people.

Convert numbers to written words for checks and invoices.

Mortgage calculator, EMI calculator — monthly payment, total interest and amortization schedule.

Track income vs. expenses

Straight-line and declining balance methods

Estimate electricity and gas bills

Compare fuel costs between vehicles

Compare deals side by side and find the best price per item. Free discount calculator.

Compare products by price per unit weight or volume. Find the best value instantly.

Convert salary between hourly, weekly, monthly and annual amounts.

Calculate compound interest with monthly contributions over time.

Estimate income tax using progressive tax brackets.

Estimate take-home pay after taxes and deductions.

Translate text to Morse code and back. Free Morse code translator.

Convert text to Braille characters

Spell out words using NATO phonetic alphabet. Free phonetic alphabet converter.

Body mass index calculator in metric or imperial. Free BMI checker with chart.

Calculate blood alcohol level and when you reach 0.0‰. Free BAC calculator with graph.

Calculate your exact age from any birth date. How old am I today?

Test your typing speed in WPM with accuracy tracking.

Calculate how long a battery will power your device — input Ah, voltage and watts

Size your solar panel and battery for off-grid Raspberry Pi and homelab setups

Calculate voltage, current, resistance, or power from any two known values.

Plan container memory — pick services from presets and check against available RAM

Estimate SD card or SSD lifespan from daily write volume and endurance rating

Calculate max requests per second from worker count and response time

Estimate inference latency and FPS for ML models on Raspberry Pi and edge devices

Interactive periodic table — click any element for weight, melting point, boiling point and more

Calculate molar mass and composition from any chemical formula.

Balance chemical equations instantly with step-by-step explanation.

Convert between pH, pOH, and hydrogen ion concentration.

Solve C₁V₁ = C₂V₂ for any missing variable.

Visualize electron configurations and orbital filling for any element.

Simulate radioactive decay with interactive charts.

Simulate projectile trajectories with adjustable angle, speed, and gravity.

Calculate voltage, current, resistance, and decode resistor color bands.

Visualize wave interference with adjustable frequency, amplitude, and phase.

Solve SUVAT equations for displacement, velocity, acceleration, and time.

Ray diagram generator for converging and diverging lenses.

Compare planets side by side: gravity, size, weight on other worlds.

Explore the solar system to scale with zoomable visualization.

Find the moon phase, illumination, and age for any date.

Translate DNA to RNA to protein with codon table visualization.

Calculate basal metabolic rate and daily energy expenditure.

Generate Punnett squares for monohybrid and dihybrid crosses.

Free running calculators, workout builders, file converters, and more.

Decode 4-band and 5-band resistor color codes instantly. Free visual resistor calculator.

Calculate the resistor needed for an LED circuit. Enter supply voltage, LED forward voltage and current.

Decode 3-digit ceramic capacitor codes (e.g. 104 = 100nF). Instant conversion to pF, nF, µF.

Calculate output voltage from a resistive voltage divider. Enter Vin, R1, R2.

Calculate frequency, duty cycle, and timing for 555 timer circuits in astable and monostable modes.

Calculate minimum PCB copper trace width for a given current, using IPC-2221 standards.

AWG wire gauge reference table with diameter, area, resistance, and max current ratings.

Calculate the time constant, charge time, and discharge curves for RC circuits.

Decode 4-band inductor color codes to inductance in µH and mH.

Calculate voltage, current, resistance, or power from any two known values.

Decode 3-digit, 4-digit, and EIA-96 SMD resistor codes to resistance values.

Convert times between cities and time zones worldwide. Free world clock.

Add or subtract days from a date, find days between two dates.

Online countdown timer and stopwatch. Set any duration.

How many weeks in a year, seconds in a day, and more time conversions.

Convert cups, tablespoons, teaspoons, ounces, ml, grams and more.

Scale recipe ingredients up or down by servings.

Convert between Celsius, Fahrenheit and Gas Mark for cooking.

Generate HTML meta tags for SEO, Open Graph and Twitter Cards.

Preview how your page looks when shared on social media.

Preview how your page appears in Google search results.

Generate a robots.txt file for search engine crawlers.

Analyze keyword density and word frequency in any text.

Generate harmonious color palettes from any base color.

Calculate and convert aspect ratios for video and images.

Calculate screen PPI/DPI from resolution and display size.

Generate favicons from text, emoji or uploaded images.