These calculators handle the unit conversions and layout math that developers reach for most. Subnet IP address ranges with the IPv4 Subnet Calculator, convert storage values with the Byte Conversion Calculator, switch between REM and PX for responsive CSS, translate RGB to CMYK for print workflows, and compute Pixels per Inch (PPI) or Aspect Ratio for any display or design asset.
Browse the most-used tools in the ranked list, or flip to the Trending tab to see what other developers are looking up right now. Every calculator is free, requires no account, and works on any device.
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Epoch Seconds to Human Date CalculatorConvert a Unix timestamp (epoch seconds) into a human-readable UTC date and time, with ISO 8601 output and full year/month/day/hour breakdown.
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Binary to Decimal ConverterConvert any binary (base 2) number to decimal (base 10) instantly. Enter your bits and get the decimal value using the positional weight formula.
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Current Unix Timestamp CalculatorConvert milliseconds to a Unix timestamp (epoch seconds). Get the current epoch now plus minutes, hours, and days since Jan 1, 1970 UTC.
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HSL to Hex Color ConverterConvert any HSL color (hue, saturation, lightness) into a hex code and RGB values instantly. Free online HSL → Hex converter with a live color preview.
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CRC Checksum CalculatorCompute CRC-8, CRC-16/CCITT-FALSE, and CRC-32 (IEEE) checksums from ASCII text. Get the cyclic redundancy check value in hex and decimal instantly.
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REM to PX ConverterCalculate REM to PX conversion with precision. Input REM value and root font size to instantly convert relative units to pixels. Streamline your web design process with this essential tool.
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Text to Binary / ASCII ConverterConvert text to binary, decimal ASCII codes, and hexadecimal. Each character becomes its 8-bit binary ASCII value. Free instant text-to-binary tool.
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F1 Score CalculatorCalculate the F1 score, precision, and recall from True Positives, False Positives, and False Negatives. Free machine-learning classification metric tool.
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Unix Timestamp to Time ConverterConvert any Unix timestamp (epoch seconds) into a UTC date and time — year, month, day, hour, minute, second, and day of the week, instantly.
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LLM VRAM Requirement CalculatorEstimate the GPU VRAM (GB) needed to run or serve a large language model from its parameter count, precision, and overhead factor.
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RGB to Hex Color ConverterConvert RGB color values (0-255) to a hex color code instantly. Enter Red, Green and Blue to get the #RRGGBB hex used in CSS and web design.
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Hex to Decimal ConverterConvert any hexadecimal (base 16) number to decimal (base 10) instantly. Enter a hex value like 1A3F and get the exact decimal result with the formula.
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Hex Color to RGB ConverterConvert any hex color code (e.g. #3498DB) to its RGB values instantly. Supports 3- and 6-digit hex codes with a live color swatch preview.
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IP Address to Binary CalculatorConvert any IPv4 address to binary, a 32-bit decimal integer, and hexadecimal. Enter four octets (0-255) for instant dotted-binary output.
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Data Storage Conversion CalculatorConvert between bytes, KB, MB, GB, TB and PB using binary (1024) or decimal (1000) systems. Fast, accurate data storage unit converter.
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Hex to Binary ConverterConvert hexadecimal (base 16) to binary (base 2) instantly. Each hex digit maps to a 4-bit nibble, plus the decimal value and digit count.
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Decimal to Hexadecimal ConverterConvert any decimal (base 10) number to hexadecimal (base 16) instantly. See the hex value and the 0x-prefixed form, with the conversion method explained.
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Hex to Decimal ConverterConvert hexadecimal (base 16) to decimal (base 10) instantly. Enter a hex value like 1A3F and get its exact decimal equivalent with the formula explained.
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PX to EM ConverterConvert pixels (px) to EM units for CSS. Enter a pixel value and base font size to get the exact em equivalent instantly.
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EM to PX ConverterConvert EM to pixels instantly. Enter an em value and your base font size (default 16px) to get the exact pixel equivalent for CSS.
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Two's Complement CalculatorConvert any decimal number to its two's complement binary form for 4, 8, 16, or 32 bits. See the stored pattern, signed value, and negation instantly.
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RGB to Hex Color ConverterConvert RGB color values (0-255) to a hex color code instantly. Enter red, green and blue to get the #RRGGBB hex string with a live color preview.
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Hex to RGB Color ConverterConvert any hex color code (#RRGGBB or #RGB) to RGB values instantly. Free, accurate hex-to-RGB converter with a live color swatch preview.
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HEX to RGB Color ConverterConvert any HEX color code to RGB values instantly. Supports 3- and 6-digit hex with or without #, and shows a live color swatch.
Frequently asked questions
What developer calculations are covered here?
You can calculate IPv4 subnets — network address, broadcast, host range, and CIDR mask — convert storage units from bits to terabytes, switch between REM and PX for any root font size, translate RGB to CMYK, compute PPI for monitors and screens, and determine aspect ratios for video or UI design work.
How accurate are the results?
These tools use deterministic formulas — binary subnet math, exact storage unit multipliers, and the CSS specification's defined REM-to-PX relationship — so outputs are precise for the values you enter. For production networking or print work, double-check critical values against your OS subnet tool, CSS spec, or color profile documentation before deploying.
Are these tools free?
Yes. Every tool is free with no login, subscription, or account required. Enter a subnet range, font size, resolution, or color value and get your result immediately on any device.
Do you store IP addresses, color codes, or other data I enter?
No. All calculations run entirely in your browser. We never collect, log, or transmit any IP addresses, pixel values, color codes, or other developer data you enter — everything stays on your device.
Which developer tools here are the most popular?
The list is ordered by real visitor usage, so the tools at the top are what developers reach for most. Check the Trending tab to see which calculators are rising in popularity lately, or Recently Added to find the latest tools in this category.
