免費線上工具

Calculate sample size for surveys, mean estimates, A/B tests, and two-group comparisons. Set confidence level, power, margin of error, and effect size. Step-by-step formulas. Free, browser-based.

Countdown and stopwatch timer for lab work. Presets for 1, 5, 10, 15, 30, and 60 minute incubations. Lap times, audio alert on completion. Free, runs in your browser.

Plan serial dilutions with fold factors, transfer volumes, and concentration at each step. Find how many steps to reach a target, or set up CFU plate-count dilutions. Full table with log₁₀ values and lab procedure. Free, browser-based.

Generate formatted lab notebook entries from your experiment details. Full entries, procedure logs, or formal experiment reports with objective, materials, procedure, observations, results, and conclusions. Copy and paste into your notebook. Free, browser-based.

Plot data as line, scatter, or bar charts from x,y pairs or separate columns. Enter lab results, calibration curves, or trial data — get an instant SVG chart with axis labels. Free, browser-based.

Graph mathematical functions y = f(x) instantly. Enter expressions like sin(x), x^2, exp(x), or multiple functions — get an SVG plot with axes, grid, and auto-scaling. Free, browser-based.

Randomize experiment run order, assign samples to treatment groups, or shuffle replicate blocks. Fisher–Yates shuffle with optional seed for reproducible lab randomization. Free, browser-based.

Free online scientific file converter: CIF, PDB, XYZ, MOL, SDF, SMILES, POSCAR, XSF, JSON, STL, OBJ. Browser-based, private, no signup.

Free private recovery tracker: streaks, urge timer, triggers, journal, and relapse support. Browser-based, no signup, data stays on your device.

Build a calm, practical positivity plan with thought reframes, short habits, and self-compassion prompts — not therapy, not toxic positivity.

Browse free fake REST APIs for testing and prototyping — JSONPlaceholder, ReqRes, FakeStore, and more with live endpoints and copy-ready URLs.

Test favicons, Apple Touch icons, and Android manifest icons for any website URL. Free favicon checker, no signup.