Random numbers

How to use a random number generator fairly

Published 25 May 2026 · 4 min read

A random number generator is simple, but the setup around it matters. Most disputes come from unclear ranges, duplicate entries, or changing the rule after the result appears. Decide those things first and the actual draw becomes boring in the best possible way.

Start with a clear range

Write down the lowest and highest possible number before you generate anything. If you have 100 tickets, the range is 1 to 100. If spreadsheet rows 2 through 251 contain entries, either renumber them 1 to 250 or make it clear that row 2 is part of the draw.

For custom ranges, use the Random Number Generator. For common ranges, presets such as 1 to 10, 1 to 20 and 1 to 100 save setup time.

Remember that endpoints are included

On Spinnit, a range of 1 to 100 can return 1, 100, or any integer between them. That is usually what people expect, but it is worth saying out loud for public draws: "I am drawing one number from 1 through 100, inclusive."

Use multiple results carefully

If you need three winners, decide whether you want three separate draws or one draw that returns three numbers. For everyday use, generating several numbers at once is fine. For a public giveaway, a cleaner approach is often to draw the main winner first, then draw backups in order so everyone understands the sequence.

Avoid accidental bias

• Do not redraw just because the result "feels weird". Streaks and surprising numbers are normal.
• Do not change the range after seeing the result.
• Do not map names to numbers after the draw. Assign numbers first, then generate.
• For names, handles or options, use a name picker tool instead of numbering them by hand.

Document simple public draws

For a classroom activity, you probably do not need proof. For a giveaway, raffle or community draw, record the entry list, the range, the draw time and the result. A screen recording or screenshot is usually enough for small informal draws, as long as the rules were clear before the draw happened.

The rule of thumb is simple: define the range, generate once, keep the result. The tool does the random part; your job is to make the setup clear enough that nobody has to guess what the result means.