Free calculators and converters

This website contains a bunch of web-based tools (you don't need to install anything, just run them here) that I have developed through the years. Use them like you want (within reason) and if you really like them, let me know.

How could you use these tools?

Calculator tools

Acceleration calculator
Convert m/s² into in/s², g
Battery calculator
What does the kWh of a battery mean?
Distance calculator
Speed x time → distance
EV mileage calculator
How much $ does your EV car use in kWh per year?
Exponential growth
Exponential growth / logarithmic decay
Fuel Cost calculator
How much $ does your car fuel cost per year?
Natural Gas calculator
How much $ does your heating gas cost?
Gladwell's 10000 hours
Deliberate practice according to Malcolm Gladwell
Speed converter
m/s ⇆ km/h, mph, mach
Frequency Calculator
Hertz -> wavelength, spectrum
Electrical power
Volt x Amp → Watt, kWh, Ah, Joule, calorie
Wavelength Calculator
Wavelength -> Hz, spectrum
Mortgage loan calculator
Calculate monthly payments for a mortgage loan

Code tools

Bash boilerplate
Create bash scripts fast with a slick boilerplate

Color tools

CMYK conversion
HTML Color list
List of named HTML colors
RGB conversion
Websafe Color list
List of websafe colors

Data tools

Bandwidth convert
Mbps ⇆ KB/s, GB/day, TB/week ...
Download calculator
file size & network speed ⇆ time to download
Data size calculator
Calculate 10 Mbps x 6.5 hours = ? GB

Music tools

Convert BPM to Hz, bar length, fractions
Audio delay
Calculate audio delay length in msec
Music Frequency
Convert pitch to musical note and wavelength
Song length
Calculate song length from BPM
Music Scale
Generate scales with frequencies
Tap your tempo
Tap to find the BPM of a song or a heartbeat

Photo tools

Aspect ratio
Image Width x Height → aspect ratio
Composition Calculator
Focal length, distance, crop factor → image composition
Depth-of-Field Calculator
Aperture, focal length, subject distance, crop → depth-of-field
DPI calculator
Print Width x Height and dpi → megapixels
Image filesize calculator
Image Width x Height JPG/RAW/PNG → bytes
Light calculator (EV)
Aperture, shutter time, ISO → Exposure Value
Megapixel calculator
Image Width x Height → megapixels
Megapixel Aspects
See megapixels in different aspect ratios

Video tools

Audio file size calculator
Estimate audio file size for (un)compressed audio
Common bitrates
List of common video bitrates (Prores, DV, DCP, MPEG...)
DCP file size
Calculate DCP audio and video filesizes
Foot-Lambert Calculator
Foot-Lambert Calculator for luminance of a screen
Screen size
Calculate screen size from diagional and aspect ratio
Video bitrate
Estimate video bitrate based on resolution, fps and bit depth
Frame rate convert
Framerate conversion with ffmpeg and sox
Video file size calculator
Estimate video file size from resolution and duration

Web tools

Content Security Policy
Create your Content Security Policy header fast!
Redirection check
Is your site redirection correctly configured?
Security Policy Framework check
Is your SPF correctly configured?
HTTPS config check
Is your site correctly configured for HTTPS?
HTML char map
View all special HTML characters «»
Emoji char map
View all special Unicode characters 🥠
HTML encoder
(HTML/URL) Encode text full of àçčéñtš
SEO Performance
Check your site on 10+ performance test sites

About this site

Development blog
New tools and other announcements
Remarks about this site? Let me know!
How grew since 2006 until now
Privacy Statement
Privacy statement (GDPR compliant)
Terms & Conditions
Terms & conditions
How to use the tools
Show me how I can use these tools