All calculators
Fifteen technical tools, each with a formula, assumptions and shareable state.
- File Transfer Time Network & data · Estimate upload or download time from file size, transfer speed and efficiency. See exact unit conversions, formula and assumptions.
- Required Transfer Speed Network & data · Calculate the bandwidth required to move a file within a target duration, including an efficiency allowance.
- Data Rate Converter Network & data · Convert network data rates between bits and bytes per second with a complete unit table.
- Storage Unit Converter Network & data · Convert decimal and binary storage units without mixing GB and GiB.
- Bitrate, Size & Duration Network & data · Calculate media file size, average bitrate or duration from the other two values.
- Aspect Ratio Calculator Image & screen · Simplify image or screen dimensions into an aspect ratio and compare common formats.
- Image Resize Dimensions Image & screen · Calculate new pixel dimensions by width, height, percentage or maximum box while preserving aspect ratio.
- Pixel Density / PPI Image & screen · Calculate screen PPI, pixel pitch and physical width and height from resolution and diagonal.
- Print Size from Pixels Image & screen · Convert image pixel dimensions to print dimensions in inches, centimetres and millimetres.
- CSS Unit Converter Image & screen · Convert CSS px, rem, em and pt with explicit root and element font-size context.
- Ratio Simplifier Ratio & proportion · Reduce a two-part integer or decimal ratio with GCD steps and normalized signs.
- Proportion Solver Ratio & proportion · Solve one missing value in a:b = c:d with cross-multiplication and verification steps.
- Time Duration Date & time · Calculate elapsed hours, minutes and seconds between two clock times, including overnight intervals.
- Days Between Dates Date & time · Calculate calendar days and weeks between ISO dates without daylight-saving errors.
- Add or Subtract a Date Date & time · Add or subtract calendar periods with explicit end-of-month and leap-year clamping.
Network & data
Transfer time, bandwidth, bitrate and unambiguous digital units.
Estimate upload or download time from file size, transfer speed and efficiency. See exact unit conversions, formula and assumptions.
→Network & data Required Transfer SpeedCalculate the bandwidth required to move a file within a target duration, including an efficiency allowance.
→Network & data Data Rate ConverterConvert network data rates between bits and bytes per second with a complete unit table.
→Network & data Storage Unit ConverterConvert decimal and binary storage units without mixing GB and GiB.
→Network & data Bitrate, Size & DurationCalculate media file size, average bitrate or duration from the other two values.
→Image & screen
Ratios, resizing, pixel density, print dimensions and CSS lengths.
Simplify image or screen dimensions into an aspect ratio and compare common formats.
→Image & screen Image Resize DimensionsCalculate new pixel dimensions by width, height, percentage or maximum box while preserving aspect ratio.
→Image & screen Pixel Density / PPICalculate screen PPI, pixel pitch and physical width and height from resolution and diagonal.
→Image & screen Print Size from PixelsConvert image pixel dimensions to print dimensions in inches, centimetres and millimetres.
→Image & screen CSS Unit ConverterConvert CSS px, rem, em and pt with explicit root and element font-size context.
→Ratio & proportion
Simplify ratios and solve proportions with visible steps.
Date & time
Elapsed time and timezone-safe calendar arithmetic.
Calculate elapsed hours, minutes and seconds between two clock times, including overnight intervals.
→Date & time Days Between DatesCalculate calendar days and weeks between ISO dates without daylight-saving errors.
→Date & time Add or Subtract a DateAdd or subtract calendar periods with explicit end-of-month and leap-year clamping.
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