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Free online tools for time, dates, text, images, audio, PDFs, SEO, DNS, and network checks

Calculators, converters, text, image, audio, PDF, SEO, DNS, and network tools, plus developer utilities. Tool pages explain their methods, examples and limits so you can check whether a result fits your task.

Processing and privacy explained on tool pages
Calculation methods, examples and limits explained
Free tools with no account required

Browse tools by category

Pick a category to see every tool in it, or jump straight to one of the tools below.

Calculators

70 tools

Loan, mortgage, interest, health, date, time, percentage, and everyday calculators.

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Converters

41 tools

Unit, number, text, time zone, data size, and data format converters.

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Developer Tools

87 tools

Formatters, validators, generators, and testers for everyday coding work.

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Internet Tools

26 tools

Subnet, IP address, domain, bandwidth, download time, and browser tools.

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Image Tools

25 tools

Compress, resize, crop, and convert images, and clean up SVG files.

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PDF & Document Tools

17 tools

Merge, split, rotate, and convert PDFs, and pull text out of PDF and Word files.

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Text Tools

10 tools

Count words, sort lines, remove duplicates, split or merge text, and clean up CSV data.

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Audio Tools

13 tools

Convert and edit audio, measure musical tempo and transcribe speech locally.

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SEO Tools

13 tools

Check page SEO, headings, canonicals, schema, links, and sitemap data, and generate the tags pages need.

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DNS Tools

4 tools

Look up A, MX, TXT, NS, and other DNS records, or compare a record across public resolvers.

Network Tools

9 tools

Ping, HTTP, whois, ASN, MAC vendor, certificate, headers, and redirects.

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Latest guides

Short how-tos that walk through a real task with one of the tools, step by step.

All guides

Oct 28, 2026

WAV vs MP3 for a voice recording

Choose between a PCM WAV source and an MP3 delivery copy for a voice recording, compare file-size settings, and keep the original for later edits.
Oct 28, 2026

Convert a voice memo to MP3

Save a Voice Memos recording as a file, convert the M4A to MP3 in Audio Converter, and check size, playback and the limits of the converted copy.
Oct 28, 2026

HEIC vs JPEG: choosing an original and a sharing copy

Understand HEIC, HEIF and JPEG, compare a measured conversion example, and choose a sharing copy without discarding the original photo.
Oct 28, 2026

Open a JSON file and find the value you need

Open a JSON file in a local editor or browser viewer, locate a value in its tree, and make a readable copy while keeping the original.

What you can do on Utilza

Calculators: add up hours, count days between dates or working days, fill in a weekly time card, find an exact age, and work out percentages and discounts.
Converters: switch data sizes between bytes, KB, MB, GB, and TB, and convert data between JSON, CSV, and YAML.
Developer tools: format and validate JSON and SQL, generate hashes and file checksums, verify JWTs, build cron schedules, and send test requests to an API.
Internet tools: work out subnets, estimate download times, and find the IP addresses and sitemaps of a domain.
Image tools: compress, resize, crop, and convert photos, and clean up SVG files.
Audio tools: convert, trim, join and edit recordings, estimate BPM and musical key, practice with a metronome, and transcribe speech on compatible WebGPU devices.
PDF & document tools: merge, split, rotate, and watermark PDFs, and turn text into PDF or Word files.
Text tools: count words, sort lines, remove duplicates, split or merge text, and clean up pasted CSV data.
SEO tools: check titles, headings, canonicals, links, and schema on a page, and build meta tags and sitemaps.
DNS tools: look up A, MX, TXT, NS, and other records, or check whether a DNS change has reached public resolvers.
Network tools: ping a host and check HTTP from many locations, look up whois and ASN, and read a certificate, headers, or a redirect chain.

How the tools work

Most tools process the numbers, text and local files you enter in your browser. DNS lookups, network checks, some SEO checks and API request tools use a server. Load From URL may also send the address to our server when a direct browser request fails. The privacy policy explains these routes and external services.

Tool pages describe their inputs, processing steps and limits. Calculator pages define their formulas so you can check a result by hand. Automated tests cover worked examples for a range of calculators and converters; this does not establish a test for every example or every tool.

Audio files are processed in your browser. Local speech transcription may download a model on first use and requires a compatible WebGPU device. Review transcripts, BPM and key estimates before using them. File size, duration and device memory limits apply.

All tools A–Z

The full list of Utilza tools in one place.