무료 온라인 도구

Calculate blackbody peak wavelength, Stefan–Boltzmann flux, and Planck spectral radiance from temperature. Wien's law and σT⁴. Free, browser-based physics tool.

Generate product SKU codes from brand, category, product, color, size, and variant fields with custom separators and sequences.

Visually build CSS gradients with a stop rail, color harmony, mesh layers, and copy-ready CSS variables.

Calculate exact age in years, months, and days from a birth date, with next birthday countdown.

Free meeting cost calculator — estimate the real cost of meetings from attendees, hourly rates, and duration. Client-side only.

Estimate body fat percentage using the US Navy circumference method with neck, waist, and hip measurements.

Free resume ATS checker — compare your resume to a job description for keyword match, missing skills, and ATS formatting risks. Private, in your browser, no signup.

Percent yield calculator free — find % yield, actual yield, or theoretical yield in grams or moles. Stoichiometry lab prep, no signup.

Generate placeholder Lorem Ipsum text by paragraphs, sentences, or words for mockups and design.

Calculate percent error, absolute error, relative error, and percent difference between measured and accepted values. Step-by-step formulas for physics and chemistry lab reports. Free, instant, browser-based.

Calculate cell count after binary fission — solve for N, N₀, divisions, generation time, or elapsed time with step-by-step growth table. Free, browser-based.

Generate prime numbers in a range or list the first N primes using the Sieve of Eratosthenes with copy-ready output.