NumLM Tools

Online calculator with an editable history tape, exact decimal mode (0.1 + 0.2 = 0.3), variables and list statistics. Keyboard-first, no ads.

Find X% of a number, what percent one number is of another, percent change, and percent difference — instantly, with the formula shown.

Count tokens and estimate API cost for GPT, Claude and Gemini. Paste text, compare models side by side. Runs entirely in your browser.

Compress JPG, PNG and WebP images in your browser. Batch, unlimited size, compress to a target KB — no upload, no signup.

Compress JPG, PNG and WebP images in your browser. Batch, unlimited size, compress to a target KB — no upload, no signup.

Convert HEIC, PNG, JPG, WebP, AVIF, GIF, BMP and SVG images in your browser. Resize, set a JPG background colour, batch convert and download as ZIP.

Fix exposure, highlights, white balance and sharpness in your browser. Auto-correct, before/after compare, full-resolution saves. No upload.

Lighten dark or backlit photos with exposure, shadows and highlights, or one-click auto brightness. Full resolution, no upload, no sign-up.

Sharpen photo edges with an unsharp mask and check the result at 100%. Saves at full resolution in your browser. Does not fix motion blur.

Remove yellow or blue casts with temperature and tint, or use auto white balance that explains what it changed. Runs in your browser.

Convert iPhone HEIC photos to JPG in your browser. Batch conversion, resize, EXIF options and ZIP download. No photo upload.

Convert iPhone HEIC photos to PNG in your browser. Batch conversion, resize, EXIF options and ZIP download. No photo upload.

Convert iPhone HEIC photos to WebP in your browser. Batch conversion, resize, EXIF options and ZIP download. No photo upload.

Convert PNG to JPG in your browser. Pick the background for transparent areas, set quality, batch convert and download a ZIP. Nothing is uploaded.

Convert JPG photos to lossless PNG in your browser, in batches with ZIP download. See how each file’s size changes before you save. No upload.

Turn WebP images saved from websites into JPG files that open in any app. Batch convert, set quality and background, download a ZIP. No upload.

Convert WebP to PNG in your browser and keep transparent backgrounds. Batch convert, resize and download a ZIP for your editing apps. No upload.

Convert JPG to WebP for faster web pages. Set quality, compare file sizes per image, batch convert and download a ZIP. Runs in your browser.

Convert PNG to WebP and keep the alpha channel while cutting file size. Set quality, batch convert and download a ZIP. Nothing leaves your device.

Render SVG icons and logos to sharp PNG at 1×–4× or an exact pixel size, with transparency kept. Batch convert and ZIP, all in your browser.

Convert AVIF images to JPG that opens in older apps and upload forms. Uses your browser’s built-in AVIF decoder; batch convert and ZIP. No upload.

Convert AVIF to lossless PNG for editing, keeping transparent areas. Resize large results, batch convert and download a ZIP. Runs in your browser.

Convert GIF images to PNG with transparency kept. Animated GIFs are detected and their first frame is saved. Batch convert and ZIP, no upload.

Convert MP3, WAV, FLAC, M4A, OGG and AIFF to MP3, WAV or FLAC in your browser. Batch + ZIP, tags kept, bit-exact lossless check. No upload.

Extract the sound from MP4, MOV, MKV and WebM videos as MP3, WAV, FLAC or the original audio without re-encoding. Big files OK, nothing is uploaded.

Convert FLAC to MP3 (128–320 kbps) in your browser. Batch + ZIP, tags and cover art kept, exact length, no upload and no size limit.

Convert FLAC to WAV without losing a bit: 24-bit and 96 kHz kept, MD5-verified, batch + ZIP. Runs in your browser, no upload.

Convert WAV to MP3 (64–320 kbps) in your browser. 24-bit and 32-bit float WAV, clipping check, exact length, batch + ZIP. No upload.

Convert MP3 to WAV for editors and CD burning. Exact length with encoder delay removed, sample rate kept, batch + ZIP. No upload.

Compress WAV to FLAC losslessly: MD5-verified bit-exact output, 16/24-bit, tags and cover art, batch + ZIP. Runs in your browser.

Convert MP3 to FLAC in your browser for apps and devices that need FLAC. Honest note: quality stays at the MP3's level. No upload.

Convert M4A (iPhone voice memos, AAC music) to MP3 in your browser. Tags and cover kept, batch + ZIP, no upload, no sign-up.

Convert MP4 videos to MP3 in your browser, even multi-GB phone videos. Pick the bitrate, cut a section, batch + ZIP. Nothing is uploaded.

Extract MP3 from iPhone and Mac MOV videos in your browser. HEVC video is fine, spatial-audio tracks handled, camera PCM kept lossless. No upload.

Pull the AAC soundtrack out of an MP4 as M4A without re-encoding: identical audio in seconds, even from huge files. Runs in your browser, no upload.

Shrink MP4, MOV, MKV and WebM videos in your browser: pick a quality or an exact target size, or lower the resolution and fps. No upload.

Make MP4 files smaller in your browser: three quality levels with a live size estimate, or an exact MB target. The result is still an MP4.

Fit any clip under Discord's upload limit: 20 MB free (raised Aug 2026), 50 MB Nitro Basic, 500 MB Nitro. Size is checked after encoding. No upload.

Convert MOV to MP4 by rewrapping, not re-encoding: same quality, done in seconds even for GB files. Or choose H.264 for maximum compatibility.

Lower a video's frame rate to 30, 24 or 15 fps by timestamp, so length and audio sync stay exact even for variable-frame-rate phone clips.

Lower video resolution to 1080p, 720p, 480p or 360p, measured on the short side so vertical phone videos stay sharp and upright. Never upscales.

Turn WebM screen recordings and downloads into H.264 MP4 that plays everywhere. Handles files without a duration and keeps the sound. No upload.

Rewrap MKV as MP4 in seconds when the video is H.264 or HEVC; other codecs are converted to H.264, and the sound to AAC when needed. No upload.

Shrink a video to attach to email: about 18 MB for Gmail's 25 MB and 14 MB for Outlook's 20 MB, since attachments grow by a third when sent.

Fit long videos under KakaoTalk's 300 MB per-file limit, or make them smaller to send faster. Runs in your browser; nothing is uploaded.

Detect and blur, pixelate or black out every face in an MP4 in your browser. Review flagged moments, add regions by hand, keep the original sound. No upload.

Put a mosaic over every face in an MP4 automatically, in your browser. Choose the block size, add regions by hand, keep the sound, download the MP4. No upload.

Cover every face in an MP4 with an opaque shape that cannot be reversed, in your browser. Automatic detection plus hand-drawn regions, sound kept. No upload.

Free online timer with alarm. Set hours, minutes and seconds or pick a preset; it keeps exact time even in a background tab and works on phones. No sign-up.

A free 1 minute timer that starts with one click. It keeps exact time in a background tab, rings until you stop it, and works on your phone. No sign-up.

A free 3 minute timer that starts with one click. It keeps exact time in a background tab, rings until you stop it, and works on your phone. No sign-up.

A free 5 minute timer that starts with one click. It keeps exact time in a background tab, rings until you stop it, and works on your phone. No sign-up.

A free 10 minute timer that starts with one click. It keeps exact time in a background tab, rings until you stop it, and works on your phone. No sign-up.

A free 15 minute timer that starts with one click. It keeps exact time in a background tab, rings until you stop it, and works on your phone. No sign-up.

A free 20 minute timer that starts with one click. It keeps exact time in a background tab, rings until you stop it, and works on your phone. No sign-up.

A free 30 minute timer that starts with one click. It keeps exact time in a background tab, rings until you stop it, and works on your phone. No sign-up.

A free 45 minute timer that starts with one click. It keeps exact time in a background tab, rings until you stop it, and works on your phone. No sign-up.

A free 1 hour timer that starts with one click. It keeps exact time in a background tab, rings until you stop it, and works on your phone. No sign-up.

Free online stopwatch accurate to 10 ms. Record laps and splits, see the fastest, slowest and average lap, copy or export CSV. Keeps running after a reload.

Count down to any date and time: days, hours, minutes and seconds, with a title and time zone. One shared link shows the same moment everywhere. Alarm at zero.

Live countdown to midnight on 1 January in your time zone: days, hours, minutes and seconds to the New Year, with an alarm at zero and a share link.

How many days until Christmas? A live countdown to 25 December in your time zone, with hours, minutes and seconds, that moves to next year by itself.

How many days until Halloween? A live countdown to 31 October in your time zone with days, hours, minutes and seconds, rolling over to next year.

How many days until Valentine's Day? A live countdown to 14 February in your time zone with days, hours, minutes and seconds, rolling over each year.

Free online Pomodoro timer: 25 min focus, 5-min breaks and a 15-min long break every 4 cycles. Presets 50/10, 45/15, 90/20, custom lengths and today's count.

Free interval timer for HIIT, Tabata, EMOM and boxing: work, rest, rounds, warm-up and cool-down with 3-2-1 beeps, a 10 s get-ready and the total time. No app.

Free Tabata timer: 20 seconds work, 10 seconds rest, 8 rounds, 4 minutes, with a 10-second get-ready, 3-2-1 beeps and a tone on every change. No app.

Free HIIT timer set to 30 s work, 15 s rest, 8 rounds, with presets for 40/20, 45/15, Tabata, EMOM and boxing, 3-2-1 beeps and the total time. No app.

Free study timer with a night-library theme and rain sounds that play only while you focus. 50-minute block, full screen, exact in a background tab.

White, pink and brown noise generated in your browser, plus rain and wind — no time limit. Mix volumes and add a sleep timer that fades out.

Rain sounds with a separate thunder slider, wind and white noise to mix in, and a timer that fades everything out for sleep. Free, no sign-up.

A focus timer that runs 25-minute sessions with 5-minute breaks and plays your ambient mix only while you focus, dipping to 30 % on breaks.

A pretty full-screen timer with eight scenery themes, a quiet tick ring and optional ambient sound. Still images, so it stays light on battery.

Online calculator with an editable history tape, exact decimal mode (0.1 + 0.2 = 0.3), variables and list statistics. Keyboard-first, no ads.

Find X% of a number, what percent one number is of another, percent change, and percent difference — instantly, with the formula shown.

Exact age in years, months and days, total days and hours, the weekday you were born and a next-birthday countdown — from a solar or Korean lunar birth date.

Calculate BMI in metric or imperial units, see your WHO category on a visual scale, the healthy weight range for your height, and Asian-Pacific thresholds.

Work out the tip and total instantly, split the bill between any number of people, round the total or the per-person amount up, and tip pre-tax or post-tax.

Count the days, weeks, months and business days between two dates, or add and subtract days, weeks, months and years from any date — with the weekday shown.

Calculate compound interest with regular contributions, any compounding frequency, and inflation-adjusted results. Year-by-year table and growth chart included.

Calculate your monthly loan payment, total interest, payoff date and full amortization schedule. Add extra payments to see the interest and time you save.

Estimate your monthly mortgage payment with taxes, insurance, PMI and HOA. See the full amortization schedule, payoff date, and when PMI drops off.

Calculate ROI, net gain and annualized return (CAGR) from what you invested and got back, or project future growth from monthly contributions.

Track every subscription and see your real monthly, yearly and 5-year cost. No signup, data stays in your browser. Export renewal dates to your calendar.

See how much more to spend to hit each card's minimum spend: amount left, days remaining, daily pace and a deadline countdown for several cards. No login.

Enter your booking’s cancellation tiers and get the exact deadline date and time for each, the penalty you’d pay, and a .ics reminder set 6 hours before.

Convert length, weight, temperature, area, volume, speed, time, data, pressure and energy — live, with every unit in the category converted at once.

Convert length and distance between centimetres, inches, feet, metres, yards, miles and more — with every unit in the category listed at once.

Convert weight and mass between kilograms, pounds, ounces, stones, grams and tonnes, using exact definitions, with all units shown side by side.

Convert Celsius, Fahrenheit, Kelvin and Rankine with the formula shown and a check against absolute zero — the conversion most calculators get wrong.

Convert between seconds, minutes, hours, days, weeks, months and years, with averaged units clearly marked so the numbers are never misleading.

Convert between 30 currencies using European Central Bank reference rates, with the rate date shown, no ads and no transfer upsell. Works offline from cache.

Count words, characters, sentences, paragraphs and lines as you type, with reading time, keyword density and Unicode-correct counting. Nothing is uploaded.

Count characters, code points, UTF-16 units and UTF-8 bytes at once, with live limit meters for X, SMS segments, meta descriptions and title tags.

Compare two texts by line, word or character. Side-by-side and unified views, ignore whitespace, case and line endings — in your browser.

Format, validate and minify JSON in your browser. 2/4/tab indent, sort keys, exact line and column errors, and big-integer safe mode. Nothing is uploaded.

Encode and decode Base64 in your browser — text, files, URL-safe, MIME line wrap and data URLs. UTF-8 correct, no uploads, no size limit.

Percent-encode and decode URLs in your browser. Choose encodeURIComponent or encodeURI, handle + as space, and break any URL into its parts.

Test JavaScript regular expressions live: match highlighting, capture group table, named groups and replace preview — with a catastrophic-backtracking guard.

Get MD5, SHA-1, SHA-256, SHA-384 and SHA-512 at once for text or a file, with HMAC, hex/Base64 output and checksum verification. All in your browser.

Generate UUID v4 or time-ordered v7 in bulk, with uppercase, braces and no-hyphen formats. Plus a UUID inspector that decodes version and timestamp.

Convert Unix timestamps to dates and back, in seconds, milliseconds, microseconds or nanoseconds. Any IANA timezone, ISO 8601, RFC 2822 and batch conversion.

Count tokens and estimate API cost for GPT, Claude and Gemini. Paste text, compare models side by side. Runs entirely in your browser.

Turn DAU, requests per user and token sizes into a monthly LLM bill. Compare models on one chart, with prompt caching and multi-turn chat. In-browser.

Paste text and see every token as a coloured block — token IDs, whitespace, chat special tokens, and which characters cost the most. Runs in your browser.

See exactly where your text is split and where chunks really overlap. Recursive and character splitters with real BPE token counts, in your browser.

Generate up to 100,000 rows of realistic fake data as CSV, JSON, NDJSON or SQL. Seeded and reproducible, 100% in your browser. No signup.

Interactive calculator for seven probability distributions: adjust sliders and watch the curve, shaded area, probability and quantiles update instantly.

Interactive normal distribution calculator: drag mean and SD sliders to see the bell curve, shaded probability, z-score and percentile update live.

Convert between z-score, probability and percentile in both directions. Live bell curve with shaded tails, one- and two-tailed critical values, full z table.

Binomial probability calculator with a live bar chart: exact P(X=k), cumulative, inverse and the normal approximation with continuity correction.

Merge, split, rotate PDFs, turn images into a PDF and export PDF pages as images — all in your browser. No upload, no signup, no file size limit.

Convert HWP, HWPX, HML, PDF, XLSX and DOCX to Markdown in your browser, then save as Word, Excel, Hangul (.hwpx) or text. No upload.

Create QR codes for links, Wi-Fi, vCards, email, SMS and phone numbers. PNG and SVG download, custom colours and error correction.

Measure download, upload, latency, jitter and bufferbloat in your browser. See whether your line is fast enough for 4K, Zoom and gaming.

Measure browser ping to a nearby edge or selected AWS regions. Shows median, p95, jitter, timeouts and the fibre-distance floor.

Measure jitter twice in the browser: at idle and under load. Shows jitter increase, loaded latency, bufferbloat and voice or gaming suitability.

Find packet-loss signals from the browser: request timeouts plus server-side TCP retransmission, with clear notes on what a browser can and cannot see.

Look up DNS records with six public resolvers. Inspect TTL, DNSSEC flags, mail records and reverse DNS, then copy a zone file or raw JSON.

Compare DNS records across six public resolvers, check expected values and remaining TTL, and monitor changes with optional repeat checks.

Inspect SPF lookup chains, DKIM public keys, DMARC policy and MX records. Get a transparent DNS configuration score and practical diagnostics.

See your public IPv4 and IPv6 address instantly. Country, nearest CDN and VPN status are shown; ISP and city are looked up only when you ask.

Look up any IP address or domain: ISP, AS number, country, city and reverse DNS. Private and reserved ranges are explained instantly, without a lookup.

Compare HTTPS and WebRTC addresses using two STUN providers. Inspect IPv4, IPv6 and local candidates without microphone or camera permissions.

Enter an IP and prefix to get network and broadcast addresses, host range, netmask, wildcard, reverse DNS name and a subnet split table — IPv4 and IPv6.

See your browser, version, OS, screen, time zone and feature support — everything a website can read about you. Nothing is sent anywhere; there is no server.

Paste a page's HTML to check 30 on-page items — title, description, headings, canonical, robots, alt text, Open Graph and JSON-LD — with the score shown.

Paste a title, description and URL to see the desktop and mobile Google result side by side, with the exact pixel width and where each one is cut.

Fill in a form to generate meta, Open Graph and Twitter Card tags, and see the link preview for Google, Facebook, X, LinkedIn, Discord, Slack and KakaoTalk.

Build a robots.txt and test any URL against it. RFC 9309 matching shows which line wins, for Googlebot, Bingbot, GPTBot and more.

Paste a URL list to build sitemap.xml — auto-split at 50,000 URLs or 50MB with an index. Or paste an existing sitemap to validate it.

Build JSON-LD for Article, Product, LocalBusiness, Event and 9 more — or paste markup to validate it. Shows which types still earn a rich result.

Count word and phrase frequency in text or HTML, with Korean, Japanese and Chinese word segmentation, stop words and a keyword placement checklist.

Build campaign URLs with utm_source, utm_medium and utm_campaign. Warns about capitals, spaces, gclid conflicts and internal links. Bulk CSV included.