Yaya Tools

Yaya Tools is a free browser-based suite of 58 single-purpose calculators and utilities for finance, math, dates, text processing, and developer encoding tasks, usable without an account or install.

What is Yaya Tools?

Yaya Tools (yayatool.com) is a website that hosts 58 free online tools, each on its own page, covering money math, statistics, dates and time zones, text cleanup, and developer encoding. You pick a tool, type values into its form (a pre-tax amount, a JSON document, a cron expression, a course credit list), and get results rendered in the browser as numbers, formatted text, or downloadable output such as a QR code image. Everything runs on the web — there is no desktop app, browser extension, or mobile app listed — and the site opens with a ⌘ K search box plus a Recent list for tools you have visited.

What makes Yaya Tools stand out?

• 58 tools grouped by task — finance and payroll (time card, overtime pay, hourly to salary, tip, discount, sales tax, compound and simple interest, loan, debt payoff, savings goal, ROI, gas cost), math and statistics, dates, text, and developer utilities.
• Developer helpers in the same place — JSON formatter/minifier/validator, JSON Diff checker, JSON to TypeScript type inference, Base64 encoder/decoder, MD5/SHA-1/SHA-256/SHA-512 hash generator, AES encrypt/decrypt, JWT decoder, URL encoder/decoder, URL parser, regex tester, crontab next-run lister, IPv4 subnet calculator, and an integer base converter for binary, octal, decimal, and hexadecimal.
• Text utilities with regex support — case converter for camelCase, snake_case, and kebab-case; line deduplicator; bulk find-and-replace; ascending, descending, or random line sorter; and a Chinese word counter that counts Hanzi, English words, and paragraphs.
• Local processing on several tools — the JWT decoder, JSON Diff checker, AES tool, and Gemini image watermark remover state that data is handled in the browser and nothing is uploaded.
• Color and QR tools — a color picker with format conversion, an image color picker that returns HEX, RGB, HSL, and a dominant palette, plus a QR code generator and a QR decoder that reads codes from an uploaded image.
• Health, school, and measurement calculators — BMI, BMR/TDEE, GPA, weighted grade calculator with the score still needed on remaining work, average/median/mode, standard deviation and variance, fraction, ratio, area and volume, concrete volume and bag estimates, pace, age, and a US unit converter.

Who should use Yaya Tools?

• Hourly workers and freelancers: the time card, overtime pay, and hourly-to-salary tools turn daily clock times into weekly hours, overtime, and estimated pay.
• Students and teachers: the GPA and grade calculators convert credits and grades into a weighted average and show the score needed on remaining work; the standard deviation and average tools handle dataset statistics.
• Developers and sysadmins: format and validate JSON, compare two JSON documents, decode a JWT locally, generate hashes, parse cron expressions, and work out subnet ranges from an IPv4 address and CIDR prefix.
• Writers and editors: strip duplicate lines, switch text between casing styles, run regex-based replacements, and count mixed Chinese and English text.

What can you do with Yaya Tools?

• Shoppers and diners: work out a sale price after discount, add sales tax to reach a final total, and split a restaurant tip across a bill.
• Commuters planning a trip: estimate fuel cost from distance, MPG, and price per gallon, or compute running or cycling pace from time and distance.
• Remote teams scheduling calls: use the time zone meeting planner to find overlapping working hours, then convert Unix timestamps to local dates.
• Developers reviewing API payloads: decode a JWT header and expiry, diff two JSON documents for added or removed fields, and infer TypeScript types from a JSON sample.

How does Yaya Tools work?

Open the tool list or press ⌘ K to search, then fill in the form fields for that calculator — for example a principal, annual rate, and term for simple interest, or two date ranges for the interval tool. The result appears on the same page, and tools such as the hash generator, subnet calculator, and QR generator produce copyable or downloadable output.

Pricing

The site presents all 58 tools as free and ready to use, with no account, signup, or paid tier mentioned on the page.

Alternatives

Omni Calculator and Calculator.net both host large free libraries of online calculators, while Yaya Tools mixes those everyday calculators with developer utilities such as JWT decoding, JSON diffing, and crontab parsing.

FAQ

Is Yaya Tools free?

Yes. The site describes its tools as free and ready to use and lists no paid plans, accounts, or download requirement. Every tool is reached through the website at yayatool.com, either from the tool list or by searching with ⌘ K.

Does Yaya Tools upload my data?

Several tools state that processing happens locally in the browser with nothing uploaded — the JWT decoder, JSON Diff checker, AES encrypt/decrypt, and the Gemini image watermark remover. For tools where the page does not say, the site does not describe a server-side storage step.

What kinds of calculators does Yaya Tools include?

It lists 58 tools: payroll and time cards, tips, discounts, sales tax, loans, debt payoff, savings goals, ROI, BMI, BMR/TDEE, GPA and grades, percentages, fractions, ratios, area and volume, concrete, pace, unit conversion, date intervals, timestamps, and time zone planning.

Are there developer tools on Yaya Tools?

Yes. The developer set includes a JSON formatter and minifier, JSON Diff, JSON to TypeScript, Base64, MD5/SHA-1/SHA-256/SHA-512 hashing, AES encryption, JWT decoding, URL encoding and parsing, a regex tester, crontab next runs, an IPv4 subnet calculator, and a GUID generator.