Random BigInt Generator

What it does

The Random BigInt Generator produces integers of arbitrary size — specify any digit count from 1 to 1,000 and get numbers far beyond JavaScript’s safe-integer limit (2⁵³−1, just 16 digits). Optionally allow negatives, generate up to 1,000 values per run, and receive them as strings, since no native number type can hold them.

Common use cases

• BigInt library testing — arbitrary-precision arithmetic verified against inputs of controlled magnitude.
• Cryptography-adjacent fixtures — numbers at RSA-like scales (a 2048-bit number is ~617 digits) for exercising big-number code paths — as test data, never as real key material.
• Overflow hunting — values just past 2⁵³ and 2⁶⁴ expose silent precision loss in JSON parsers, databases, and languages.
• Financial and scientific edge cases — precision testing where floats quietly betray you.

Settings

• Digits — 1 to 1,000; the first digit is non-zero so the count is exact.
• Allow negative — include negative values.
• How many — 1 to 1,000 numbers per run.
• Seed — identical seed + settings = identical numbers.

Privacy note

Numbers are generated locally in your browser and never uploaded. They are seeded, reproducible test values — never use them as cryptographic keys or secrets, which must come from secure randomness.

FAQ

Why strings instead of numbers? JavaScript’s Number silently corrupts integers above 2⁵³−1. Strings survive JSON and every pipeline; convert with BigInt(value) at the edges.

The JSON trap to test for: JSON.parse turns big numeric literals into lossy floats. Send your parser a 30-digit value from this tool and check what comes out — that one test catches a famously sneaky bug class.

Are these primes? No — uniform random digits. For primes, use the Random Prime generator.