64 fast tools.
Zero backend.
Calculators, generators and diagnostics that solve one concrete task in seconds. For deeper system design, use Toolkit.
AI
Tokens, load, limits and budgets for model-powered applications.
Words to tokens
Estimate token count from word count for quick context and cost planning.
Open tool →AIPages to tokens
Estimate words and tokens from document pages to plan context windows.
Open tool →AIMonthly token volume
Size monthly token usage from users, requests and tokens per request.
Open tool →AIAPI retry cost
Measure how retries increase actual calls and monthly cost.
Open tool →AIAI image budget
Project daily, monthly and annual AI image-generation spend.
Open tool →AIAI transcription budget
Calculate transcription spend at scale from minutes and usage days.
Open tool →AIRPM / TPM planner
Check whether estimated load fits request-per-minute and token-per-minute limits.
Open tool →AIConcurrency estimator
Use Little’s Law to estimate concurrent in-flight requests.
Open tool →RAG
Chunks, overlap, embeddings, retrieval and context without a backend.
RAG chunk count
Estimate chunk count from corpus size, chunk size and overlap.
Open tool →RAGRAG overlap overhead
Quantify extra repeated tokens introduced by chunk overlap.
Open tool →RAGVector storage
Estimate raw embedding and metadata storage for a vector index.
Open tool →RAGEmbedding cost
Calculate embedding cost from corpus tokens and price per million tokens.
Open tool →RAGTop-k context budget
Check how many tokens retrieved chunks consume before the model call.
Open tool →RAGReranking budget
Project reranking volume and cost from candidates per query.
Open tool →RAGRAG corpus size planner
Convert documents and pages into approximate words and tokens.
Open tool →RAGRAG retrieval latency
Break down retrieval latency before the LLM call.
Open tool →Evals
Metrics, sample size, agreement and error budgets for better evaluation.
Precision, recall and F1
Calculate classification metrics from TP, FP and FN.
Open tool →EvalsClassification accuracy
Calculate overall accuracy and error from a binary confusion matrix.
Open tool →EvalsCohen’s kappa
Estimate binary-rater agreement corrected for chance agreement.
Open tool →EvalsPass@k
Estimate probability of at least one correct solution within k samples.
Open tool →EvalsSample size for proportions
Estimate sample size for a proportion at a target margin of error.
Open tool →EvalsProportion confidence interval
Calculate an approximate normal confidence interval for an observed rate.
Open tool →EvalsWeighted score
Combine four criteria with explicit weights for reproducible comparisons.
Open tool →EvalsSLO error budget
Turn a reliability SLO into allowed errors and remaining error budget.
Open tool →Development & data
Local transforms for JSON, JWT, hashes, bases and URLs.
JWT decoder
Decode JWT header and payload locally without claiming signature verification.
Open tool →Development & dataQuery string parser
Convert URL query parameters into readable JSON.
Open tool →Development & dataBase converter 2–36
Convert integers between binary, octal, decimal, hexadecimal and bases up to 36.
Open tool →Development & dataValidate and sort JSON
Validate JSON and recursively sort keys for more stable diffs.
Open tool →Development & dataSecure token generator
Generate cryptographically random bytes in-browser and return hex + Base64URL.
Open tool →Development & dataSHA-512 hash
Calculate SHA-512 locally with Web Crypto.
Open tool →Development & dataJSON minifier
Validate and remove unnecessary whitespace from JSON.
Open tool →Development & dataData size converter
Convert B, KiB, MiB, GiB and TiB using binary powers.
Open tool →SEO & web
Technical generators for metadata, hreflang, sitemaps and Firebase.
UTM Builder
Build a URL with correctly encoded UTM parameters.
Open tool →SEO & webCanonical tag generator
Generate a rel=canonical tag from a normalized URL.
Open tool →SEO & webES/EN hreflang builder
Generate reciprocal ES, EN and x-default hreflang tags.
Open tool →SEO & webMeta robots builder
Compose a robots meta tag with indexing, following and snippet controls.
Open tool →SEO & webOpen Graph builder
Generate basic OG tags for title, description, URL and image.
Open tool →SEO & webFAQ Schema Builder
Generate FAQPage JSON-LD for a question and answer.
Open tool →SEO & webSitemap entry builder
Build an XML <url> node for a sitemap.
Open tool →SEO & webFirebase redirect builder
Generate a firebase.json redirect block without deploying anything.
Open tool →Business
ROI, capacity, operating cost and automation decisions.
ROI calculator
Calculate return on investment from total benefit and cost.
Open tool →BusinessBreak-even calculator
Calculate units needed to cover fixed costs from unit contribution margin.
Open tool →BusinessTeam meeting cost
Convert attendees, hourly cost and duration into direct meeting cost.
Open tool →BusinessHuman review capacity
Size how many outputs a human review team can inspect per period.
Open tool →BusinessSupport deflection savings
Estimate gross savings when some support tickets avoid human handling.
Open tool →BusinessAI + human review cost
Combine model inference cost and human sampling cost for a review pipeline.
Open tool →BusinessAutomation capacity
Convert weekly workload and automatable share into monthly hours freed.
Open tool →BusinessPayback period
Estimate months to recover an investment from steady monthly savings.
Open tool →Media
Image, audio, video, subtitles and physical or digital sizes.
Megapixel calculator
Convert width and height into total pixels and megapixels.
Open tool →MediaPrint size by DPI
Calculate physical print size from pixel dimensions and DPI.
Open tool →MediaAspect ratio
Reduce width and height to an integer ratio and detect orientation.
Open tool →MediaUncompressed image size
Estimate raw image memory from resolution, channels and bits per channel.
Open tool →MediaPCM audio size
Estimate uncompressed PCM audio size.
Open tool →MediaVideo size by bitrate
Convert bitrate and duration into approximate video file size.
Open tool →MediaVoice-over duration
Estimate voice-over duration from word count and speaking rate.
Open tool →MediaSubtitle reading speed
Calculate characters per second to assess subtitle reading load.
Open tool →Text
Editorial metrics and fast transforms without sending text away.
Sentence statistics
Count words, sentences, characters and average sentence length.
Open tool →TextKeyword density
Measure keyword or phrase frequency against total word count.
Open tool →TextLines to CSV
Convert a line list into a correctly quoted one-column CSV.
Open tool →TextCSV to list
Extract the first column of a simple CSV as a line list.
Open tool →TextTitle Case
Convert text to title case with a simple predictable rule.
Open tool →TextText length budget
Compare text characters and words with a target limit.
Open tool →TextLexical diversity
Count unique words and calculate type-token ratio as a descriptive signal.
Open tool →TextRead-aloud time
Estimate spoken reading duration from word count and speaking rate.
Open tool →