Small tools that get one thing done.
Twenty-three tools for the numbers, documents and small jobs you deal with every week. Everything runs in your browser — no install, no account, no uploads.
All 23 tools, sorted by what you need
Splitting, discounts, loans and what things add up to over time.
TipSplit
Split a bill between up to 20 people, choose a tip, round up, and screenshot the receipt.
Percent Calculator
X% of a number, what percent one number is of another, and percent change — three answers in one screen.
Discount Calculator
Final price after a percent off, money saved, or the real discount when you only know the sale price.
Loan Calculator
Monthly payment, total interest and the full payoff figure for any fixed-rate loan.
Mortgage Calculator
Monthly payment, total interest and payoff date — plus what one extra payment a month would save.
Compound Interest
What a starting amount plus monthly contributions turns into over time, with the interest split out.
Salary Converter
Hourly pay to a yearly salary, or a salary back to an hourly rate. Monthly, weekly and daily figures included.
Retirement Calculator
What your savings grow into by the time you stop working, and what that is worth in today’s money.
Merge, split and shrink files without sending them anywhere.
Merge PDF
Several PDFs into one file, in the order you pick. Your documents are never uploaded.
Split PDF
Pull out a page range like 1-3, 7 — or save every page as its own file.
Images to PDF
Photos and scans into one PDF, on A4, Letter, or a page that matches the image.
Image Compressor
Shrink a photo inside the tab — no upload, no signup. JPEG or WebP, straight to your downloads.
Count, convert and clean up words and structured data.
Word Counter
Words, characters, sentences and paragraphs, plus reading and speaking time. Nothing leaves your browser.
Case Converter
UPPERCASE, Title Case, camelCase, snake_case — seven styles, one click each.
JSON Formatter
Format, minify or validate JSON, and get told exactly which line broke it.
Password Generator
Cryptographically random passwords with a live entropy readout. Generated locally, never stored.
Days between dates, and what time it is somewhere else.
Date Calculator
Days between two dates, or the date N days from now. Weekdays and month lengths handled.
Time Zone Converter
Compare a time across cities, including the day change and daylight saving.
Age Calculator
Exact age in years, months and days, total days lived, and a countdown to your next birthday.
Body metrics, unit conversions and a QR code for a link.
BMI Calculator
Body mass index in metric or imperial, the range it lands in, and the healthy weight band for your height.
Calorie Calculator
Daily calories for your goal, with the protein that goes with it. Metric or imperial.
Unit Converter
Length, weight, volume and temperature. Type a value once and read every unit at the same time.
QR Code Generator
Turn a link into a QR code on your own device. Nothing uploaded, and the code never expires.
Pricing
- Lifetime access — pay once, use forever
- Every tool on this site, fully unlocked
- Every tool added later, included free
- No subscription, no renewal, no ads
- Works on phone, tablet and desktop
Early birdUse code EARLY40 at checkout for 40% off — $17.40 instead of $29. First 50 buyers.
Get All-Access — $29Instant delivery by email · 30-day refund policy
Runs on your device
Your numbers and text are processed in the browser. Nothing is sent to a server to get a result.
No account
Open the page and use it. There is nothing to sign up for, and nothing to verify by email.
Fast pages, no clutter
Each tool is a single lightweight page. No pop-ups, no countdowns, no newsletter wall.
More tools every week
Twenty-three tools are live today and more are added every week. If there is a small task you do repeatedly and hate doing, tell us — support@koumen.net. The most requested ones get built first.
Get All-Access — $29