SILENT MAJORITYOFFLINE TOOLS

147 free offline utilities

Fix CSV. Split PDFs. Format JSON.

Free tools that work in your browser, without uploading your files. No account required.

  • Runs in your browser
  • Files never leave your device
  • Keep a standalone copy

147 tools available

Tool directory

All offline tools

CSV Fixer

Repair encoding, normalize dates, and protect leading zeros before reopening data in Excel.

FeaturedDownloads: —
Open toolDownload ZIP

PDF Split & Merge

Split pages into separate PDFs or combine multiple documents in the order you choose.

FilesDownloads: —New
Open toolDownload HTML

Image Resizer

Resize and convert batches of JPEG, PNG, and WebP images without uploading them.

FilesDownloads: —
Open toolDownload HTML

JSON Formatter

Format, validate, sort, and minify JSON with clear syntax-error feedback.

DataDownloads: —
Open toolDownload HTML

Text Cleaner

Clean whitespace, blank lines, duplicates, sorting, and line endings in one pass.

TextDownloads: —
Open toolDownload HTML

File Hash

Calculate SHA-256, SHA-384, and SHA-512 checksums for local files.

SecurityDownloads: —
Open toolDownload HTML

Base64 Converter

Encode or decode Unicode text and small files with UTF-8-safe conversion.

DeveloperDownloads: —
Open toolDownload HTML

Timestamp Converter

Translate local dates, ISO 8601 values, and Unix timestamps precisely.

DeveloperDownloads: —
Open toolDownload HTML

Password Generator

Create strong passwords locally with cryptographically secure randomness.

SecurityDownloads: —
Open toolDownload HTML

URL Encoder

Encode and decode full URLs or individual query values with UTF-8-safe handling.

DeveloperDownloads: —New
Open toolDownload HTML

Markdown Preview

Draft common Markdown safely and export a clean, portable HTML document.

WritingDownloads: —New
Open toolDownload HTML

Text Diff

Compare two versions line by line and export a standard unified diff.

TextDownloads: —New
Open toolDownload HTML

Invisible Character Inspector

Reveal and remove zero-width spaces, direction marks, and hidden Unicode controls.

TextDownloads: —New
Open toolDownload HTML

Filename Sanitizer

Make filename lists unique and safe across Windows, macOS, and Linux.

FilesDownloads: —New
Open toolDownload HTML

JSON Lines Converter

Convert JSON arrays to JSONL or NDJSON and back with line-level error reports.

DataDownloads: —New
Open toolDownload HTML

IP Range Overlap Checker

Compare existing and planned IPv4 ranges to find overlaps before connecting networks.

NetworkDownloads: —
Open toolDownload HTML

Network Capacity Planner

Turn application demand, concurrency, growth, and utilization targets into a shared uplink requirement.

NetworkDownloads: —
Open toolDownload HTML

Availability & Downtime Budget

Calculate an availability target’s downtime allowance and remaining budget from outage durations.

NetworkDownloads: —
Open toolDownload HTML

TCP Window & BDP Calculator

Calculate bandwidth-delay product and the ideal throughput ceiling imposed by a receive window.

NetworkDownloads: —
Open toolDownload HTML

Optical Link Budget Calculator

Check minimum receive power, engineering margin, and receiver overload from supplied optical specifications.

NetworkDownloads: —
Open toolDownload HTML

DHCP Pool Planner

Remove gateways, reservations, and exclusions from a LAN scope and check dynamic lease capacity.

NetworkDownloads: —
Open toolDownload HTML

DNS Record Builder & Checker

Create A, AAAA, CNAME, and MX record lines from a spreadsheet and catch conflicting aliases.

NetworkDownloads: —
Open toolDownload HTML

Firewall Communication Matrix Checker

Compare a spreadsheet of expected traffic decisions with ordered IPv4 rules and export every mismatch.

NetworkDownloads: —
Open toolDownload HTML

Network Configuration Diff

Compare ordered configuration lines before and after a change, with original line numbers for review.

NetworkDownloads: —
Open toolDownload HTML

Network Acceptance Test Checker

Evaluate measured loss, latency, jitter, and throughput against explicit per-test acceptance thresholds.

NetworkDownloads: —
Open toolDownload HTML

Interface Counter Delta Analyzer

Calculate per-direction throughput and utilization from two 32-bit or 64-bit octet-counter snapshots.

NetworkDownloads: —
Open toolDownload HTML

IPv4 Subnet Calculator

Calculate network boundaries, masks, host ranges, and /31 point-to-point addresses.

NetworkDownloads: —
Open toolDownload HTML

VLSM Subnet Planner

Allocate non-overlapping LAN subnets from a parent network using required host counts.

NetworkDownloads: —
Open toolDownload HTML

CIDR Aggregator & Range Converter

Convert IPv4 ranges to CIDRs and merge adjacent or duplicate networks without adding addresses.

NetworkDownloads: —
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CIDR Exclusion Calculator

Subtract IPv4 exceptions from network lists and export the exact remaining CIDRs.

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Open toolDownload HTML

IP Network Membership Checker

Check which IPv4 addresses belong to supplied networks, with every matching range shown.

NetworkDownloads: —
Open toolDownload HTML

IPv6 Subnet & Address Calculator

Normalize IPv6 text and calculate prefix boundaries and exact address counts.

NetworkDownloads: —
Open toolDownload HTML

VLAN & IP Plan Checker

Check a VLAN plan for duplicate IDs, overlapping subnets, and invalid gateway addresses.

NetworkDownloads: —
Open toolDownload HTML

Route Longest Prefix Match

Find the longest matching IPv4 routes and show equally specific next-hop candidates.

NetworkDownloads: —
Open toolDownload HTML

Subnet & Wildcard Mask Converter

Convert between IPv4 prefix lengths, contiguous subnet masks, and inverse wildcard masks.

NetworkDownloads: —
Open toolDownload HTML

MAC Address Normalizer

Convert 48-bit MAC addresses to colon, hyphen, and Cisco formats and inspect address bits.

NetworkDownloads: —
Open toolDownload HTML

Network Transfer Time Calculator

Estimate transfer duration from data size, line rate, and assumed effective utilization.

NetworkDownloads: —
Open toolDownload HTML

Required Bandwidth Calculator

Calculate the line rate needed to finish a backup or transfer within a specified window.

NetworkDownloads: —
Open toolDownload HTML

MTU & TCP MSS Calculator

Calculate inner MTU, advertised TCP MSS, and payload budget with explicit encapsulation overhead.

NetworkDownloads: —
Open toolDownload HTML

IPv4 Traffic Rule Checker

Evaluate an IPv4 packet against a simplified ordered rule list and identify the first matching rule.

NetworkDownloads: —
Open toolDownload HTML

tcpdump Capture Filter Builder

Build validated libpcap filters for protocol, source, destination, and destination ports.

NetworkDownloads: —
Open toolDownload HTML

Network Address Redactor

Replace recognized IPv4, IPv6, MAC addresses, and specified hostnames with consistent labels in logs.

NetworkDownloads: —
Open toolDownload HTML

Reverse DNS Name Generator

Generate in-addr.arpa and ip6.arpa owner names from IPv4 and IPv6 addresses.

NetworkDownloads: —
Open toolDownload HTML

CSV Merge & Deduplicate

Merge multiple CSV or TSV files and remove exact duplicate rows locally.

DataDownloads: —
Open toolDownload HTML

EXIF Metadata Cleaner

Remove embedded metadata from JPEG, PNG, and WebP images by re-encoding locally.

PrivacyDownloads: —
Open toolDownload HTML

Duplicate File Finder

Find byte-for-byte duplicate files in a selected folder using local SHA-256 hashes.

FilesDownloads: —
Open toolDownload HTML

QR Code Generator & Reader

Generate QR codes from text or read QR codes from local images without network access.

DataDownloads: —
Open toolDownload HTML

Title Case Converter

Capitalize the first letter of each word.

TransformDownloads: —
Open toolDownload HTML

Sentence Case Converter

Normalize text and capitalize sentence openings.

TransformDownloads: —
Open toolDownload HTML

Alternating Case Converter

Alternate lower and uppercase letters.

TransformDownloads: —
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Snake Case Converter

Convert words and identifiers to snake_case.

TransformDownloads: —
Open toolDownload HTML

Kebab Case Converter

Convert words and identifiers to kebab-case.

TransformDownloads: —
Open toolDownload HTML

Camel Case Converter

Convert words and identifiers to camelCase.

TransformDownloads: —
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Pascal Case Converter

Convert words and identifiers to PascalCase.

TransformDownloads: —
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Constant Case Converter

Convert words and identifiers to CONSTANT_CASE.

TransformDownloads: —
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Dot Case Converter

Convert words and identifiers to dot.case.

TransformDownloads: —
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Trim Lines

Remove leading and trailing whitespace from every line.

TransformDownloads: —
Open toolDownload HTML

Collapse Spaces

Replace repeated horizontal whitespace with one space.

TransformDownloads: —
Open toolDownload HTML

Line Shuffler

Randomize line order with device-generated randomness.

TransformDownloads: —
Open toolDownload HTML

Line Number Remover

Remove common numeric prefixes from lines.

TransformDownloads: —
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Paragraph Unwrapper

Join wrapped lines while preserving paragraph breaks.

TransformDownloads: —
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Spaces to Tabs

Replace repeated indentation spaces with tabs.

TransformDownloads: —
Open toolDownload HTML

Line Ending Normalizer

Normalize mixed CRLF and CR line endings to LF.

TransformDownloads: —
Open toolDownload HTML

Final Newline Adder

Ensure text ends with exactly one newline.

TransformDownloads: —
Open toolDownload HTML

Punctuation Remover

Remove Unicode punctuation while keeping letters and numbers.

TransformDownloads: —
Open toolDownload HTML

HTML Tag Stripper

Extract readable text from an HTML fragment.

TransformDownloads: —
Open toolDownload HTML

HTML Escaper

Escape HTML-sensitive characters for safe display.

TransformDownloads: —
Open toolDownload HTML

JSON String Escaper

Escape text as a valid JSON string value.

TransformDownloads: —
Open toolDownload HTML

JSON String Unescaper

Decode JSON backslash escapes into plain text.

TransformDownloads: —
Open toolDownload HTML

JavaScript String Escaper

Escape text for a double-quoted JavaScript string.

TransformDownloads: —
Open toolDownload HTML

CSV Field Quoter

Quote and escape one CSV field per input line.

TransformDownloads: —
Open toolDownload HTML

ROT13 Converter

Apply the reversible ROT13 letter substitution.

TransformDownloads: —
Open toolDownload HTML

Word Order Reverser

Reverse words while retaining simple spacing.

TransformDownloads: —
Open toolDownload HTML

Unique Word Extractor

List each distinct word once, ignoring case.

TransformDownloads: —
Open toolDownload HTML

Duplicate Word Remover

Remove immediately repeated words from prose.

TransformDownloads: —
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Diacritic Remover

Remove combining accent marks from letters.

TransformDownloads: —
Open toolDownload HTML

Fullwidth ASCII Converter

Convert fullwidth ASCII and spaces to halfwidth forms.

TransformDownloads: —
Open toolDownload HTML

Smart Quote Normalizer

Replace typographic quotes and dashes with plain equivalents.

TransformDownloads: —
Open toolDownload HTML

Whitespace Visualizer

Reveal spaces, tabs, and line endings with visible marks.

TransformDownloads: —
Open toolDownload HTML

Reading Time Calculator

Estimate reading and speaking time from word count.

AnalyzeDownloads: —
Open toolDownload HTML

Keyword Density Checker

Measure exact keyword use within a passage.

AnalyzeDownloads: —
Open toolDownload HTML

Palindrome Checker

Check text while ignoring case and punctuation.

AnalyzeDownloads: —
Open toolDownload HTML

Anagram Checker

Compare two values while ignoring spaces and punctuation.

AnalyzeDownloads: —
Open toolDownload HTML

Regular Expression Tester

List every JavaScript regular-expression match.

AnalyzeDownloads: —
Open toolDownload HTML

Email Extractor

Extract unique email-like addresses from text.

AnalyzeDownloads: —
Open toolDownload HTML

Phone Number Extractor

Extract likely international phone numbers for review.

AnalyzeDownloads: —
Open toolDownload HTML

Hex Color Extractor

Extract unique three-, four-, six-, and eight-digit hex colors.

AnalyzeDownloads: —
Open toolDownload HTML

Duplicate Line Finder

Report repeated non-empty lines and their counts.

AnalyzeDownloads: —
Open toolDownload HTML

Longest Line Finder

Rank the ten longest lines with their original numbers.

AnalyzeDownloads: —
Open toolDownload HTML

Text Statistics

Summarize lines, words, characters, bytes, and sentence count.

AnalyzeDownloads: —
Open toolDownload HTML

UUID v4 Generator

Generate cryptographically random UUID version 4 values.

GenerateDownloads: —
Open toolDownload HTML

Nano ID Generator

Generate compact URL-safe random identifiers.

GenerateDownloads: —
Open toolDownload HTML

Random Hex Generator

Generate secure random hexadecimal tokens.

GenerateDownloads: —
Open toolDownload HTML

Random Integer Generator

Generate unbiased integers from zero through one million.

GenerateDownloads: —
Open toolDownload HTML

Lorem Ipsum Generator

Generate temporary Latin-style layout copy.

GenerateDownloads: —
Open toolDownload HTML

Sample Name Generator

Generate clearly fictional names for mockups and tests.

GenerateDownloads: —
Open toolDownload HTML

Sample Email Generator

Generate reserved example-domain email addresses.

GenerateDownloads: —
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Color Palette Generator

Generate random hex colors for quick visual exploration.

GenerateDownloads: —
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Random Date Generator

Generate ISO dates between 2000 and 2030.

GenerateDownloads: —
Open toolDownload HTML

Sample CSV Generator

Generate harmless sample rows for spreadsheet testing.

GenerateDownloads: —
Open toolDownload HTML

Sample JSON Generator

Generate a valid JSON array for parser and UI tests.

GenerateDownloads: —
Open toolDownload HTML

Number Sequence Generator

Generate a one-based integer sequence.

GenerateDownloads: —
Open toolDownload HTML

Placeholder Slug Generator

Generate predictable placeholder slugs for prototypes.

GenerateDownloads: —
Open toolDownload HTML

Binary / Decimal Converter

Convert binary integers to decimal.

ConvertDownloads: —
Open toolDownload HTML

Hex / Decimal Converter

Convert hexadecimal integers to decimal.

ConvertDownloads: —
Open toolDownload HTML

Decimal Base Converter

Convert a decimal integer to any base from 2 through 36.

ConvertDownloads: —
Open toolDownload HTML

Roman Numeral Converter

Convert decimal integers from 1 through 3999 to Roman numerals.

ConvertDownloads: —
Open toolDownload HTML

Byte Unit Converter

Convert bytes to binary and decimal storage units.

ConvertDownloads: —
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Length Converter

Convert meters to common metric and imperial lengths.

ConvertDownloads: —
Open toolDownload HTML

Mass Converter

Convert kilograms to metric and imperial weights.

ConvertDownloads: —
Open toolDownload HTML

Temperature Converter

Convert Celsius to Fahrenheit and Kelvin.

ConvertDownloads: —
Open toolDownload HTML

Volume Converter

Convert liters to common liquid-volume units.

ConvertDownloads: —
Open toolDownload HTML

Speed Converter

Convert kilometers per hour to other speed units.

ConvertDownloads: —
Open toolDownload HTML

Duration Converter

Break a duration in seconds into larger units.

ConvertDownloads: —
Open toolDownload HTML

Angle Converter

Convert degrees to radians, turns, and gradians.

ConvertDownloads: —
Open toolDownload HTML

HEX to RGB Converter

Convert a three-, six-, or eight-digit hex color to RGB values.

ConvertDownloads: —
Open toolDownload HTML

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Your data stays on your deviceLocal processing keeps sensitive work private
No purchase or account requiredJust download the tool you need
Free tools, built to lastMore useful tools will be added over time

Privacy by design

Your work files
stay with you.

Our offline tools process files locally instead of sending them to a web service. That makes them a practical choice for client data and internal documents.

  1. 01
    No uploads

    Your files are processed locally and never sent to our servers.

  2. 02
    No account

    We do not ask for your email address or a user registration.

  3. 03
    No subscription

    Use the tools you download without another monthly bill.

Support the project

Pay what it was
worth to you.

Every tool is free. If one saved you a little time, a coffee-sized contribution helps fund the next one. Supporting us is always optional and never unlocks extra features.

Support via Stripe

Give only if you want to. Secure payment is handled on Stripe's hosted checkout page.

FAQ

Good to know

Are these tools really free?

Yes. Every tool listed here is free to download. Optional contributions help fund future development and maintenance.

Do you receive the contents of my files?

No. The offline version processes files on your device without uploading them to an external server.

How are download counts measured?

The hosted site records aggregate page views, visible tool cards, clicks, successful processing, copies, and download actions so we can improve the directory. The counter stores no cookie, account, IP address, filename, referrer, or tool input, and downloaded offline tools send no analytics.

Will you add more tools?

Yes. We plan to keep adding small, practical tools for file management and everyday office work.