8 Free Developer Utilities Nobody Told You About

Every developer has that drawer of bookmarked sites they open three times a week and can't remember how they lived without. Today I'm opening mine and sharing 8 free utilities from ElysiaTools that handle the kind of small, annoying tasks that somehow eat up 20 minutes every time they come up.

These tools are completely free, run entirely in your browser, and require no sign-up.

1. Coordinate Format Converter

Your GPS gives you 40.7128, -74.0060. Your map API wants 40° 42′ 46.1″ N, 74° 0′ 21.6″ W. The Maidenhead locator system used by amateur radio operators wants something like FN30as — and some obscure GIS library you're using wants UTM format.

The Coordinate Format Converter handles all of these in one place. Paste in any format — decimal degrees, DMS, DM, or UTM — and get back any other format with configurable precision and separator styles.

This means no more hunting for the right formula every time you need to convert a coordinate for a different system.

Use it when: Integrating GPS data from multiple sources, building map features, or converting coordinates for GIS software.

2. Gregorian ↔ Islamic Calendar Converter

Islamic calendar dates follow a lunar system of roughly 354 days, making them about 11 days shorter than the Gregorian calendar. This means the same Islamic date drifts through the Gregorian calendar year — Ramadan shifts roughly 11 days earlier each Gregorian year.

The Gregorian to Islamic and Islamic to Gregorian converters handle bidirectional conversion. Each Islamic month is named — from Muharram ("The Sacred Month") through Dhu al-Hijjah ("The Month of Pilgrimage") — and the tool shows the meaning and Chinese name alongside the date.

Use it when: Building apps that serve Muslim users, calculating Islamic event dates for calendars, or working with historical Islamic records.

3. UTM Zone Calculator

The Universal Transverse Mercator (UTM) coordinate system divides the world into 60 zones, each 6° of longitude wide. If you've ever tried to manually figure out which UTM zone a set of coordinates falls into — and dealt with the edge cases like Norway and Svalbard — you'll appreciate having a tool that gets it right.

The UTM Zone Calculator takes a latitude/longitude pair and returns the zone number, zone letter, hemisphere, and central meridian. It handles the special cases for Norway (zones 32V) and Svalbard (zones 31X, 33X, 35X, 37X) automatically.

Use it when: Working with UTM-based coordinate systems, military/aviation applications, or topo map coordinate reference systems.

4. Geohash Generator & Decoder

Geohash encodes geographic coordinates into a short string — u4pruydqqrj9 represents a location accurate to roughly 153m × 153m. It's compact, URL-safe, and used by systems like MongoDB's geospatial queries and various geocoding APIs.

The Geohash Generator takes lat/lon coordinates and produces a geohash with configurable precision (1–12 characters). The Geohash Decoder reverses the process, accepting any valid geohash string and returning the decoded coordinates plus the bounding box and error margin.

The error margin changes dramatically with precision: 1 character gives you ~2,500 km accuracy, while 9 characters gives you ~2.4 m accuracy.

Use it when: Shortening GPS coordinates for URLs, storing locations in space-constrained databases, or building proximity-based features.

5. Maidenhead Locator Converter

Amateur radio operators don't use street addresses or decimal coordinates — they use the Maidenhead locator system, which encodes locations as short grid squares like FN31pr. A 6-character locator like FN31pr gives roughly 4.6 km × 2.3 km accuracy, while an extended 8-character locator can achieve ~115m accuracy.

The Coordinates to Maidenhead and Maidenhead to Coordinates converters handle both directions. The tool breaks down the locator into field (2 letters), square (2 digits), subsquare (2 letters), and extended square (2 digits) so you can understand the precision of any locator you encounter.

Use it when: Communicating with amateur radio operators, logging contacts for awards like WAS or DXCC, or decoding QTH locators in satellite tracking software.

6. Zodiac Date Calculator

Yes, it's for fun. But the Zodiac Date Calculator is actually well-built: it correctly handles the edge cases around cusp dates (Capricorn ends January 19, Aquarius starts January 20) and returns not just the zodiac sign but also the element (Earth, Air, Fire, Water), ruling planet, and key personality traits.

You can also show all 12 zodiac signs with their date ranges, elements, and ruling planets in one view — useful if you're building a horoscope feature or just need to settle a debate at a dinner party.

Use it when: Building astrology-related features, generating birthday content, or prototyping gamified user profiles.

7. Checksum Comparator

You download a file and the download page says the SHA-256 hash should be e3b0c44298fc1c149afbf4c8996fb924. You run your local copy through a tool and get e3b0c44298fc1c149afbf4c8996fb924. Do they match? Yes. Did you actually check, or did you just assume? The Checksum Comparator makes it fast and obvious.

Paste two checksums, and it normalizes them (strips spaces, colons, and hyphens), detects the hash type (CRC-32 through SHA-512), and tells you definitively whether they match — and if they don't, it tells you exactly how many characters differ and in what way.

Use it when: Verifying software downloads, checking file integrity after transfers, or auditing cryptographic checksums in CI/CD pipelines.

8. British-American English Converter

English spelling varies between the US and UK — color/colour, honor/honour, recognize/recognise. If you've ever had to produce content for both audiences and manually searched for every instance of "ize" vs "ise" endings, this one saves a ton of time.

The British-American English Converter uses AI to intelligently handle context — so it won't, for example, mangle a proper noun or a technical term that shouldn't be converted.

Use it when: Adapting documentation for different English markets, localizing content, or converting between British and American English style guides.

Wrapping Up

These 8 tools represent a small slice of what's available at elysiatools.com, which offers over 1,600 free browser-based utilities. The pattern across all of them: no sign-up, no ads, no API key required, just a URL you can bookmark and use immediately.

The most useful ones on this list for developers are probably the Coordinate Format Converter and the Checksum Comparator — the kind of utilities that come up unexpectedly and waste your afternoon if you don't have them handy.

Which utilities are in your permanent bookmark bar? I'd love to hear what you're using — drop a comment below.