RandomNr

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Random Number Table Generator

Build a classic random number table with the rows, columns and digit width you set.

Random Number Table Generator

39281 04716 ...

10 rows by 5 columns

Table size

Digits per cell

Each cell is a group of this many digits

How to use the random number table

  1. Set the rows, the columns and the digits per cell.
  2. Press Generate table for a fresh grid of random digits.
  3. Copy it with tabs between cells, or download a CSV that opens as a grid.

The book that made random digits famous

Before computers were common, statisticians drew their randomness from printed tables, and the most famous is the RAND Corporation's A Million Random Digits with 100,000 Normal Deviates, published in 1955. Its digits were produced from 1947 onward by an electronic roulette wheel wired to a computer, then filtered and tested before printing. The book became a standard reference for statisticians, pollsters, quality control engineers and Monte Carlo simulation, and it stayed in use for decades. Each grid this page generates is the same kind of object, drawn instead from your browser cryptographic source.

How to draw a sample from the table

The classic procedure still works and is a good classroom exercise. Number your population, say 1 to 80. Pick an arbitrary starting cell in the table. Read digits in fixed size groups, two digits for a population up to 99. Accept each group that falls inside your range, skip groups outside it and any repeats, and continue until you have your sample. Reading across rows or down columns both work, as long as you fix the rule before you start.

StepExample with digits 39281 04716
Read in pairs39, 28, 10, 47, 16
Keep values 1 to 8039, 28, 10, 47, 16 all valid
Skip repeatsnone here, so the sample is 39, 28, 10, 47, 16

What a fair table looks like

In a table of truly random digits every digit from 0 to 9 is equally likely, so each should appear about a tenth of the time. A default grid here holds 10 rows of 5 cells with 5 digits each, 250 digits in all, so each digit should turn up roughly 25 times, with ordinary variation either side. Counting digit frequencies in an exported table is a neat first statistics exercise, the same check RAND ran, at book scale, before publishing.

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Frequently asked questions

What is a random number table

It is a grid of random digits arranged in rows and columns, the kind printed in statistics textbooks for drawing samples by hand.

Can I set the digit width

Yes. Choose how many digits sit in each cell, for example five digit groups, up to twelve digits per cell.

How big can the table be

Up to 200 rows by 20 columns, with up to twelve digits per cell.

How do I export it

Copy places the table on your clipboard with tabs between cells, and download CSV writes one row per line for a spreadsheet.

Is it free

Yes, free and with no sign up. Every table is built in your browser and nothing you enter leaves your device.

Related generators

For a single draw rather than a table, use the random number generator, or build a long single column with the random number list generator.