Calculation guide: units, fractions, statistics and rounding

Choose a measurement type, enter a value, then select the units you have and need. Compatible units stay together; temperature conversions account for the different scale origins. Volume includes metric units and U.S. customary liquid units.

Steps

1. Choose Length, Area, Mass, Volume or Temperature and enter the value to convert.
2. Select the starting and target units, or use Swap units to reverse them.
3. Select Convert units. Check the displayed units with the result, then copy the number if needed.

Available options

Value

1

From unit

Metre · Centimetre · Millimetre · Kilometre · Inch · Foot · Yard · Mile · Square metre · Square centimetre · Square kilometre · Hectare · Acre · Square foot · Kilogram · Gram · Milligram · Tonne · Pound · Ounce · Litre · Millilitre · U.S. fluid ounce · U.S. cup · U.S. liquid pint · U.S. liquid quart · U.S. liquid gallon · Celsius · Fahrenheit · Kelvin

To unit

Metre · Centimetre · Millimetre · Kilometre · Inch · Foot · Yard · Mile · Square metre · Square centimetre · Square kilometre · Hectare · Acre · Square foot · Kilogram · Gram · Milligram · Tonne · Pound · Ounce · Litre · Millilitre · U.S. fluid ounce · U.S. cup · U.S. liquid pint · U.S. liquid quart · U.S. liquid gallon · Celsius · Fahrenheit · Kelvin

Decimal places

10

Capabilities and limits

• Supports the listed length, area, mass, volume and temperature units. Volume cups, fluid ounces, pints, quarts and gallons are U.S. customary liquid measures; temperatures below absolute zero are rejected.
• Results are calculated in your browser; refresh clears unsaved work.

Choose the question you need to answer. Each mode labels its two inputs and shows the formula, so you can see which value is the whole or starting point.

Steps

1. Choose whether to find a share, an amount from a percentage, or a percentage change.
2. Enter the two values using the labels shown for that calculation and check the formula.
3. Calculate, then read the result with its label and percent sign where applicable. Copy or download it if needed.

Available options

Calculation

What is X% of Y? · X is what % of Y? · Percent change

First value

20

Second value

100

Decimal places

10

Capabilities and limits

• A whole or starting value of zero makes a percentage ratio undefined and is rejected. The “percentage of a value” mode can use zero.
• Percent change compares two numbers; it cannot make periods, audience sizes, or measurement methods comparable. Normalize your data before interpreting the result.
• Results are calculated in this browser; refresh clears unsaved work.

Enter a pixel width and height to see their simplified ratio. Set a new width or height to calculate the other side. Fractional pixels are rounded to the nearest whole pixel.

Steps

1. Enter the original width and height in pixels.
2. Choose which new side to set, then enter its pixel size.
3. Calculate to see the simplified ratio and proportional new dimensions; copy or download the note.

Available options

Original width

1920

Original height

1080

Set new

Width · Height

New side (px)

1280

Capabilities and limits

• Dimensions must be positive whole pixels from 1 to 1,000,000,000. Results that round to zero or exceed this range are rejected.
• This calculates dimensions only; it does not resize, crop, or alter a file. All input stays in this browser.
• This is the pixel width-to-height ratio. Video with non-square pixels can have a different displayed aspect ratio.

Enter a data amount, choose source and target units, and compare decimal (powers of 1,000) with binary (powers of 1,024) sizes. The result always names its unit.

Steps

1. Enter an amount and choose a common pair, or select the two units directly.
2. Check whether each unit is in bits or bytes and whether its prefix is decimal or binary.
3. Convert, then copy the number with its target unit or download the full equality.

Available options

Value

1

From unit

bit · byte · kbit · Mbit · Gbit · Tbit · kB · MB · GB · TB · Kibit · Mibit · Gibit · Tibit · KiB · MiB · GiB · TiB

To unit

bit · byte · kbit · Mbit · Gbit · Tbit · kB · MB · GB · TB · Kibit · Mibit · Gibit · Tibit · KiB · MiB · GiB · TiB

Decimal places

10

Capabilities and limits

• Values must be nonnegative and no greater than 1e100; nonzero values too small to represent are rejected. Display rounding does not make a large or fractional result exact.
• This converts data amounts, not transfer rates such as Mb/s; it does not inspect or change a file. All input stays in this browser.
• Some interfaces label binary sizes as MB or GB. Check the source definition or raw byte count before selecting a unit.

Convert a large signed integer between bases 2–36 without losing digits. Choose a common base pair or select both bases, then copy the exact result.

Steps

1. Choose a common conversion or set the input and output bases from 2 to 36.
2. Enter one integer in the selected input base. For example, use 0xff with input base 16.
3. Select “Convert number base”, check the labeled result, then copy its digits or download them.

Available options

Input base

10

Output base

16

Capabilities and limits

• One integer at a time, up to 4,096 input characters including sign, prefix and separators. The converted value can be longer.
• Only whole numbers are supported. Matching 0b, 0o and 0x prefixes and single underscores between digits are accepted; other punctuation, internal spaces and fractions are rejected. Surrounding whitespace is trimmed.
• Output digits a–z are lowercase. Leading zeros, prefixes and a negative sign on zero are not preserved. Negative values use a mathematical minus sign, not a fixed-width two's-complement bit pattern.

Draw one or more whole numbers from an inclusive range. Choose independent draws or a sample without repeats, then copy or download the ordered list.

Steps

1. Choose whether numbers may repeat. Use No repeats when selecting distinct numbered items.
2. Enter inclusive minimum and maximum integers, then the number of draws. Check the range capacity shown below the fields.
3. Generate a new draw, then copy or download the ordered numbers, one per line.

Available options

Minimum (inclusive)

1

Maximum (inclusive)

100

Number of results

10

No repeated numbers

Off by default

Capabilities and limits

• Generates 1–1,000 integers per draw within the browser's safe-integer range. A no-repeats draw cannot exceed the number of integers in the range.
• The browser's cryptographic random source is required. Results are not saved or independently verifiable as lottery records.

Use exact fraction arithmetic for tape measurements, recipes and other values that should not be rounded before calculation. Enter two values, choose an operation and see the reduced fraction, readable mixed number and decimal.

Steps

1. Enter two values, such as 21 3/8 and 1 7/16.
2. Choose add, subtract, multiply or divide and check the live preview.
3. Calculate, then copy the mixed number, reduced fraction or decimal. The downloaded TXT contains the exact fraction.

Capabilities and limits

• Enter numbers only. This tool does not convert feet, inches, cups or other units; use the same unit for both measurements.
• Accepts simple fractions, mixed numbers with a space, whole numbers and finite decimals up to 18 decimal places. Each input is limited to 120 characters.
• The decimal is rounded to 12 places when it does not terminate; the fraction remains exact. Calculation stays in your browser.

Choose a number list for population or sample variance and standard deviation. Choose CSV to analyze one numeric column without converting decimal strings to floating-point numbers; check blank and missing cells before exporting the report.

Steps

1. Choose number list or CSV column. Paste numbers for a list; for CSV, paste a table or choose one UTF-8 file.
2. For a list, choose population or sample. For CSV, choose delimiter, header setting and a numeric column; check blank, missing and invalid cells.
3. Calculate and inspect the result. Copy the list standard deviation or the complete JSON report; download the full JSON. Switching input modes keeps each input in this tab and clears the prior result.

Available options

Input mode

Number list · CSV column

List mode uses floating-point variance; CSV mode preserves exact decimal strings for a selected column.

Numeric column

Enter as needed

Header row

First row is a header · No header row

Input delimiter

Comma · Semicolon · Tab · Pipe

Missing-value markers

Enter as needed

Capabilities and limits

• List: up to 10,000 finite numbers and 100,000 characters; commas, semicolons, whitespace and scientific notation are accepted. No headers, units or thousands separators. Magnitudes must be at most 1e100; nonzero values that underflow to zero are rejected.
• List variance and standard deviation use floating-point arithmetic and the selected population or sample divisor. CSV mode provides count, minimum, maximum, sum, mean and median; it does not calculate CSV variance or a maximum-minus-minimum range.
• CSV: up to 1 MiB of pasted UTF-8 text or one 10 MiB UTF-8 CSV/TSV/TXT file, 200,000 cells including a header row, and 1,000 columns. Headers must be unique and nonempty when used; every row must have equal width.
• CSV numeric cells accept signed decimals or scientific notation: at most 110 characters per token, 100 coefficient digits and an exponent of at most three digits with magnitude at most 100. Blank cells are counted separately; exact, case-sensitive missing markers are optional (up to 20 markers, 100 characters each and 2,048 characters in the marker input).
• CSV minimum, maximum, sum and median are exact decimal strings. The mean is rounded half away from zero when required to at least 18 decimal places, or the largest input scale if greater; meanRounded and meanDecimalPlaces record this. Five original numeric records are previewed, with all statistics and counts in the JSON report. Processing stays in this browser.

Enter one value and weight per row to combine scores, quantities or other comparable values. Inspect the total weight and each contribution before using the result.

Steps

1. Enter one value and its weight per row, or paste two spreadsheet columns.
2. Check that every row uses the same weight style and that the total reflects the group you intend to average.
3. Calculate, inspect the normalized weight shares, then copy the average or download the JSON details.

Capabilities and limits

• Use 1–100 pairs. Values may be negative; weights must be nonnegative. Each number can have up to nine decimal places and magnitude up to one billion.
• Use the same weight style in every row: plain relative numbers or percentages. The calculator normalizes by the actual total, which need not be 100.
• Numbers are calculated from decimal input exactly before a repeating answer is rounded to 12 places. Input stays in this browser.

Round one decimal number with a clear tie rule. Choose fixed decimal places, significant figures, or scientific notation. Negative places round to tens and larger powers of ten.

Steps

1. Enter one number, then choose decimal places, significant figures, or scientific notation.
2. Set the number of places or significant digits and choose a rounding rule. Inspect the live preview.
3. Format the number, then copy the result or download it as text.

Available options

Task

Exact decimal · Scientific notation · Significant figures

Decimal places

2

Rounding rule

half-up · half-even · floor · ceil · truncate

Significant digits

6

Significant figures

3

Capabilities and limits

• Accepts up to 300 decimal digits and exponents from −300 to 300. Decimal places range from −12 to 100; significant digits from 1 to 100.
• Uses decimal-string arithmetic, not binary floating-point conversion. Match the tie rule used by your target system.
• Input is processed in this browser. No account is needed.

Enter two known X/Y pairs and a target X to estimate Y on the straight line between them. The result is extrapolation when the target lies outside the known X interval.

Steps

1. Enter two known X/Y coordinate pairs and keep each axis in consistent units.
2. Enter the target X and check the live estimate and any extrapolation warning.
3. Calculate, copy Y or the full JSON, or download the JSON with the exact rational result.

Capabilities and limits

• One pair of known points and one target X; X₁ must differ from X₂. No table lookup, curve fitting or inverse X-at-Y mode.
• Plain decimal values within ±1 trillion, at most 12 decimal places and 40 characters each. Y is rounded to 12 places when its exact decimal repeats.
• Inputs remain in this browser; measurement uncertainty and the physical validity of a linear assumption are not assessed.

Enter how many distinct items you have (n) and how many you choose (r). Compare combinations, where order is ignored, with permutations, where order changes the result. Each item can be chosen once.

Steps

1. Enter the total number of distinct items n and the number selected r in the visible fields.
2. Read nCr for groups where order does not matter, or nPr for arrangements where positions matter.
3. Copy either exact count, expand long results, or download the JSON containing both counts.

Capabilities and limits

• Whole numbers only: 0 ≤ n ≤ 10,000 and 0 ≤ r ≤ min(n, 1,000). The items are distinct and selected without replacement.
• Both results are exact integers. Long answers show a short preview; copy, expand or download the full digits.
• This counts outcomes, not the possible lists themselves or the probability of a particular outcome. No account or upload is needed.

Paste one candidate per line, choose how many to draw, and decide whether identical labels count once or as separate entries. The selected lines are returned in random order.

Steps

1. Paste or type one candidate per line. Check how many eligible entries remain after the duplicate choice.
2. Set the visible pick count from 1 to the number of eligible entries; choose whether to remove identical labels first.
3. Draw once, then copy or download the selected lines. Run again for an independent draw.

Capabilities and limits

• Up to 50,000 input lines per draw. Blank lines are ignored and surrounding spaces are trimmed; duplicate matching is exact and case-sensitive.
• Each input position can be chosen only once in one draw. If repeated labels are kept, the same label may appear more than once; each new run starts over and can pick past winners again.
• Uses browser cryptographic random values. It does not provide a public seed, audit trail or certification for an externally governed raffle. Input stays in the browser.