무료 온라인 도구
268+ free online tools for PDF, images, SEO, developers, color, and productivity. Fast, browser-based, and private — no signup, no installs, no limits. Search above or browse by category below.
Total tools26810.8K total uses
Categories13Active categories
Most usedJSON Formatter4.1K uses
Recently addedExperiment RandomizerNewest tool
Astronomical Unit Converter
Convert astronomical units (AU) to light-years, parsecs, kilometers, meters, and miles. Enter any distance and get instant conversions with formulas. Free, browser-based.
Used 0 times•Updated never
Exoplanet Habitability Calculator
Assess exoplanet habitability with habitable zone, equilibrium temperature, and Earth Similarity Index (ESI). Presets for Earth, Proxima b, and Kepler-186f. Free, browser-based.
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Constellation Finder
Find constellations by RA/Dec coordinates, search all 88 IAU constellations by name, or list what's visible tonight from your location. Free, browser-based.
Used 0 times•Updated never
Earthquake Magnitude Converter
Convert between earthquake magnitude scales — Mw, Ms, ML (Richter), mb, and Md. Estimates seismic moment, energy in joules, and TNT equivalent. Free, browser-based.
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Richter Scale Calculator
Calculate Richter magnitude from seismograph amplitude and distance, explore effects and energy for any ML value, or compare two magnitudes. Free, browser-based.
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Wind Chill Calculator
Calculate wind chill (feels-like temperature) from air temperature and wind speed. Uses the official NWS / Environment Canada 2001 formula with frostbite risk guidance. Free, browser-based.
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Humidity Calculator
Calculate relative humidity, dew point, wet-bulb temperature, vapor pressure, absolute humidity, and mixing ratio from dry-bulb readings. Free, browser-based.
Used 0 times•Updated never
Air Density Calculator
Calculate air density from temperature, pressure, and humidity, or from altitude. Shows kg/m³, virtual temperature, speed of sound, and comparison to sea-level standard. Free, browser-based.
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Altitude Pressure Calculator
Convert between altitude and atmospheric pressure using the barometric formula or ISA standard atmosphere. Pressure in hPa, inHg, kPa, and more. Free, browser-based.
Used 0 times•Updated never
Soil Density Calculator
Calculate soil bulk density, moisture content, porosity, and void ratio from sample mass and volume. Supports metric (g, cm³) and imperial (lb, ft³). Free, browser-based.
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Carbon Footprint Calculator
Estimate your annual carbon footprint from car travel, flights, home electricity, and natural gas. Compare to global averages with regional grid factors. Free, browser-based.
Used 0 times•Updated never