Free tools

Practical utilities for learners, teachers, and people building courses—no account required.

• Reading time, word count & readabilityEstimate how long your lesson or article takes to read, with Flesch readability scores—runs in your browser.
• Course workload & study hours plannerSpread modules across weeks, set hours per module, and see a week-by-week calendar with optional weekly caps.
• Spaced repetition schedule generatorGenerate review dates from your learn date—fixed 1-3-7-style intervals or a simplified SM-2 curve.
• Module outline generatorTurn a topic into a draft module outline with objectives and lesson titles—then build the full course in Ailurn.
• Quiz grade calculatorPoints or percentage to pass/fail, US letter & GPA, or rough UK / German / 1–10 mappings—all in your browser.
• Syllabus week counterCurrent syllabus week, exam week, and days or calendar weeks until your final—from week 1 and exam dates.
• Prompt & token length estimatorRough token size for teaching prompts and lesson drafts, with context-window comparison—all in your browser.
• Open Graph & Twitter Card previewFetch public pages and preview how shared links may look using og: and twitter: tags.
• SERP snippet previewTune title and meta description length with a Google-style snippet mockup for course and lesson pages.
• JSON-LD generator (Course, FAQ, Article, Breadcrumb)Build schema.org JSON-LD for educational pages—copy into a script tag and validate.
• UTM campaign URL builderTag links for launches, email, and social with presets for cohorts and webinars.
• Markdown previewPreview lesson notes and READMEs in Markdown—rendered locally in your browser.
• URL slug generatorTurn titles into clean slugs for modules, lessons, and glossary paths.
• Title case & headline formatterAP-style, Chicago-style, or sentence case for lesson titles and email subjects.
• Duplicate line & paragraph removerDeduplicate pasted notes or transcripts before turning them into lessons.
• Robots.txt generatorDraft crawler rules for your course site—snippets, quick checks, optional fetch of public robots.txt.
• XML sitemap checkerFetch a public sitemap or index and review URL entries for your learning site.
• HTTP header & redirect checkerFollow redirects and inspect headers when migrating lesson or course URLs.
• SSL / TLS certificate checkerView certificate metadata for an https:// host—quick HTTPS sanity check.
• Keyword Golden Ratio (KGR) calculatorKGR from your own search volume and allintitle counts—niche course topics.
• AI crawler rules checkerPaste or fetch robots.txt and compare common AI training crawlers.
• Sitemap → internal link ideasPath-prefix ideas from your XML sitemap to strengthen hubs between modules.
• Conversion rate calculatorVisitors to enrollments or completions—funnel math for cohorts.
• Meeting & office-hours costPeople × hours × rate for live cohort sessions and training blocks.
• CPC & ROAS calculatorAd spend, clicks, and revenue—paid metrics for course and webinar campaigns.
• Discount & sale price calculatorPercent off and final price for courses, bundles, and promotions.
• SaaS metrics calculatorMRR, churn, LTV:CAC, and implied lifetime for subscription learning products.
• Writing style signalsSentence and vocabulary stats for lesson drafts—not an AI/human detector.
• Regex testerJavaScript RegExp against sample text—matches, flags, and copy for docs/API examples.
• JSON formatter & minifierPretty-print or minify JSON for READMEs, tutorials, and API snippets.
• Cron expression helperField order and labels for Unix-style cron—jobs, reminders, and automation.
• Base64 encoder & decoderUTF-8 safe encode/decode for API learning and small payloads.
• Hashtag generatorTags from lesson titles and launch copy—optional stop-word filtering.