Cryptographically Secure · Range Settings · Lottery Mode · Batch Generation · Distribution Statistics
Zero Dependencies · Local Processing · Never Uploads DataOur online random number generator is a pure frontend tool — no software installation required, just open the page and use it. It supports everything from simple random number draws to complex batch generation and statistical analysis, suitable for lotteries, data sampling, teaching demonstrations, game randomization, and more.
All random numbers are generated via the browser's built-in Web Crypto API, the highest-security random number generation interface available in browsers, based on the high-entropy random source provided by the operating system, ensuring that each number has an exactly equal probability of appearing.
In Single or Batch mode, you can freely set the minimum and maximum values. Supports any integer interval, such as 1-100, 1000-9999, or even negative ranges like -50 to 50. The system automatically validates range legality, ensuring the maximum is greater than the minimum.
Lottery mode provides two methods: Range Lottery is ideal for drawing by number (e.g., drawing 10 winning numbers from 1-500 at an annual party); List Lottery is ideal for drawing by name (e.g., drawing winners from a participant list). Both modes guarantee no duplicates — a number or person that has already won will not be drawn again.
Batch Generation mode can generate up to 10,000 random numbers at once, supporting copy to clipboard or direct download as a text file. Enabling the "comma-separated" option allows you to paste directly into Excel for further analysis.
Distribution Statistics mode lets you verify the uniformity of random numbers. Under ideal conditions, each number should appear roughly the same number of times. We provide a frequency histogram plus statistical metrics such as average, median, and standard deviation to help you intuitively understand the characteristics of random distribution.
Select "Single Generation" mode, set the minimum and maximum values, and click the "Generate" button to get a random number. Batch mode generates up to 10,000 numbers at once, supporting copy to clipboard or direct download as a text file. Enabling the comma-separated option lets you paste directly into Excel for analysis.
Lottery mode offers two methods: "Range Lottery" for drawing by number (e.g., drawing 10 winners from 1-500) and "List Lottery" for drawing by name (e.g., drawing winners from a participant list). Both modes guarantee no duplicates.
Distribution statistics mode verifies random number uniformity. The system generates a specified number of random values and calculates frequency for each, displayed as a histogram, along with average, median, and standard deviation metrics.
Random number generators are widely used in both technical and everyday contexts. In tech, cryptographically secure random numbers generate keys, session tokens, and verification codes. In data analysis, random sampling is fundamental to statistical surveys and quality control. In game development, random numbers drive loot drops, damage calculation, and procedural map generation.
In daily life, random numbers are used in raffles, random grouping, and random sorting. This tool uses a cryptographically secure random number generator (based on the Web Crypto API), ensuring fairness and unpredictability for formal raffles and sensitive scenarios.
Generating "true" random numbers on a computer is extremely difficult because computer programs are inherently deterministic. The common solution uses physical entropy sources (hardware noise, mouse movement, keyboard timing, etc.) to produce a seed, then generates cryptographically secure pseudo-random numbers. This tool's Web Crypto API uses the operating system's entropy source, producing cryptographically secure randomness.
Ordinary Math.random() is not suitable for security-sensitive scenarios because its deterministic implementation can be predicted. A Cryptographically Secure Pseudo-Random Number Generator (CSPRNG) uses complex mathematical transformations to ensure that even knowing part of the output does not reveal the rest. Always use CSPRNG for high-security scenarios like raffles, password generation, and encryption keys.
Yes, completely fair. We use the browser's built-in Web Crypto API (crypto.getRandomValues) to generate cryptographically secure random numbers, not ordinary Math.random(). This algorithm is based on entropy sources provided by the operating system (such as hardware noise, mouse movement, keyboard timing, etc.), ensuring that each number within the specified range has an exactly equal probability of appearing and cannot be predicted or manipulated.
Lottery mode supports two forms: ① Range lottery — set a minimum and maximum value, and draw a specified number of unique winning numbers from the range, supporting ranges up to millions; ② List lottery — paste a list of participants (one per line), and randomly draw a specified number of winners from the list. There is no hard limit on list length (recommend keeping it under 10,000 for performance). All drawing is done locally in your browser.
Batch generation mode supports generating up to 10,000 random numbers per session. If the "avoid duplicates" option is enabled, the count cannot exceed the range size (for example, a range of 1-100 allows at most 100 unique numbers). Results support one-click copy and export as a text file download.
The distribution statistics feature visually shows the statistical characteristics of generated random numbers, including: a frequency histogram for each number, plus metrics such as average, median, standard deviation, maximum, and minimum. This helps verify the uniformity of random distribution and is suitable for teaching demonstrations and data analysis scenarios.
Ordinary Math.random() is a pseudo-random number generator (PRNG) based on a deterministic algorithm seed. While sufficient for daily use, it is not suitable for security-sensitive scenarios. Our tool uses crypto.getRandomValues(), which calls the operating system's high-entropy random source (such as /dev/urandom, Windows CSP, hardware RNG). This is a cryptographically secure random number generator (CSPRNG) that meets cryptographic security requirements and is better suited for lotteries, key generation, and other scenarios that demand fairness.
Absolutely not. All random number generation, list drawing, and statistical calculations are performed locally in your browser. No data is uploaded to any server. You can use this tool offline, and you can safely enter any participant information knowing your data is processed entirely on your device.