免費線上工具

Simulate DNA/RNA mutations — substitutions, insertions, deletions, and seeded random SNPs with highlighted output and mutation log. Free, browser-based.

Create professional invoices with line items, tax, and totals — preview, print, or download as PDF.

Free UTM campaign link lab — build, preview, and parse UTM-tagged URLs for ads and campaigns. Fully client-side.

Free Minecraft stack calculator — convert item counts into stacks of 64, 16, or unstackable leftovers. Copy a clear shopping summary.

Find codons in RNA or DNA — search AUG, stop codons, scan reading frames, and view codon frequencies. Free, instant, browser-based.

Generate Instagram hashtag sets by niche, topic, and style — instant, curated, and ready to paste.

Free vocabulary match practice tool — tap matching word and meaning pairs. Optional timer and instant pair feedback.

Calculate safety factor, margin of safety, and utilization from strength and stress or load and capacity. Modes: SF from stress, SF from load, allowable stress, required strength, and design pass/fail check. Material yield presets. Metric (MPa, kN) and imperial (ksi, lbf). Free, browser-based.

Calculate microscope total magnification, field of view from FN, and actual specimen size from image measurements — eyepiece × objective. Free, browser-based.

Free online audio volume booster — amplify quiet MP3, WAV, or M4A files in your browser. Boost gain up to +20 dB privately with no upload or signup.

Create printable sales receipts with items, tax, payment details — preview, print, or download as PDF.

Download YouTube video thumbnails in every available resolution from a link or video ID.