Section 1: Questions about the Service and Software

Q1.1: I use RANDOM.ORG a lot. How can I show my appreciation?

Excellent question! We suggest you either register for a RANDOM.ORG account or make a donation to Concern. In case you don’t know them, Concern is a charity that helps poor people in the third world achieve self-sustainable improvements in their lifestyles. We recommend them because we agree with their mission statement (which they unfortunately removed as per January 2010, but it used to be here) and because they are pretty efficient compared to many of the other charities we have looked at. If you decide to make a donation to Concern because of RANDOM.ORG, it’d be great if you could tell us about it, since Concern don’t automatically do that. (We suppose they have better things to do.) And it makes us so happy!

Q1.2: Is the source code for the generator available?

Not currently, no. Maybe we’ll make it available as open source some day.

Q1.3: Can I download the generator software and run it on my own computer?

No. It’s not just the software you’d need, but also three radios (or one, at any rate), which must be carefully adjusted to pick up atmospheric noise at the right volume. It’s not completely trivial to set up.

Q1.4: Could someone affect the numbers by broadcasting a radio signal?

RANDOM.ORG uses radio receivers to pick up atmospheric noise, which is then used to generate random numbers. The radios are tuned between stations. A possible attack on the generator is therefore to broadcast on the frequencies that the RANDOM.ORG radios use in order to affect the generator. However, radio frequency attacks of this type would be difficult for a variety of reasons. First, the frequencies that the radios use are not published, so an attacker would have to broadcast across all frequencies of all bands used for FM and AMbroadcasting. Second, this is not an attack that can be launched from anywhere in the world, only reasonably close to the generator. RANDOM.ORG currently has radio receivers in several different countries, which would make it difficult to coordinate this type of attack. Third, if an attacker actually did succeed at broadcasting highly regular signals (e.g., perfect sine waves) at exactly the right frequencies from the right locations, then the RANDOM.ORG real-time statistics would pick up the drop in quality very rapidly. In particular, the Source Purity and Information Entropy tests would start failing dramatically, which would raise an alert.

Q1.5: Will RANDOM.ORG be around in X years?

Probably, depending on your value for X. We have run the service since 1998 with no real interruptions, and it is more popular than ever.

Q1.6: Does RANDOM.ORG perform custom jobs that require randomness?

Yes. Perhaps you need more numbers than it’s possible to get via the web forms, or perhaps you need them in a format that isn’t supported. In those cases, we can set up a custom job for you to supply the numbers. We also act as independent observers for drawings and competitions via the Third-Party Draw Service.

There is typically a charge associated with custom jobs. You can email us for further details.

Q1.7: I seem not to be receiving emails from RANDOM.ORG. What is wrong?

RANDOM.ORG will send email to you when you register for a Premium Account or if you have forgotten your password. It can also email you if you use the Premium Generator or the Third-Party Draw Service. If you have problems receiving any of these emails, please check your spam filter configuration. It should be set to accept emails from If you are still experiencing problems, please let us know.

Q1.8: Can I advertise on RANDOM.ORG or buy a paid link?


Section 2: Questions about the Numbers

Q2.1: How can you be sure the numbers are really random?

Oddly enough, it is theoretically impossible to prove that a random number generator is really random. Rather, you analyse an increasing amount of numbers produced by a given generator, and depending on the results, your confidence in the generator increases (or decreases, as the case may be). This is explained in more detail on my Statistical Analysis page, which also contains two studies of the numbers generated by RANDOM.ORG, both of which concluded that the numbers are sound. In addition, the continually updated Real-Time Statisticspage gives you an indication of the quality of the numbers produced over time.

Q2.2: Have the numbers been certified by an independent third party?

The numbers produced by RANDOM.ORG have been evaluated by eCOGRA, which is is a non-profit regulatory body that acts as the independent standards authority of the online gaming industry. For a typical gambling site, eCOGRA will oversee many aspects of its operation, including financial aspects, such as payout percentages. RANDOM.ORG is not a gambling site, so in our case, eCOGRA only evaluated the quality of the random numbers. They found that RANDOM.ORG consistently produced random numbers across scaling intervals and issued a certificate with their conclusion: ecogra-2009-06-25.pdf (1 page, 52 Kb)

The numbers and software have also been evaluated by TST Global (part of Gaming Labs International) who in 2011 examined the generator for use in games hosted on Malta. TST’s report stated that RANDOM.ORG ‘distributes numbers with sufficient non-predictability and fair distribution to particular outcomes’ and concluded that it ‘complies with the requirements of the applicable Technical Standard in the jurisdiction of Malta as regulated by The Lotteries and Gaming Authority (LGA).’

Most recently, our service was evaluated by by Gaming Labs International who in 2012 examined the generator for use in lottery games in the UK. Their report concluded that it ‘distributes numbers with sufficient non-predictability, fair distribution and lack of bias to particular outcomes’ and that it ‘complies with the requirements of the applicable Technical Standard in the UK Remote Gambling jurisdiction, as regulated by the United Kingdom Gambling Commission (UKGC).’ Further details are available upon request.

Additionally, RANDOM.ORG is specifically accredited to generate randomness for use in games regulated by the following:

Certification documents for specific jurisdictions are available upon request.

Q2.3: Should the tables of generated numbers be read across or down?

For any form that allows the numbers to be formatted in multiple columns, the numbers are generated on a per-row basis, not per-column. Hence, if you want to read them in the order they were generated, you should read them across. Since they’re random numbers, it doesn’t really matter whether you do it one way or the other, but you should pick one of the two ways and read that way consistently.

Q2.4: Are the numbers available in a secure fashion?

Yes, since April 2007 you can access the server via

We should probably note that while fetching the numbers via secure HTTP would protect them from being observed while in transit, anyone genuinely concerned with security should not trust anyone else (including RANDOM.ORG) to generate their cryptographic keys.

Q2.5: What if I need more numbers than is allowed by the forms?

Currently, there isn’t a lot you can do, except email us and tell us this is a problem for you (see also question 1.6). For some of the forms, the limit is there because it requires time to generate random numbers and the server is pretty busy. For other forms, the restriction is related to the available memory in our servers.

If you can do your own programming, you may be able to use the pregenerated files. They contain large amounts of pregenerated raw random data that you can download and use as you please. However, you will probably need to process the files for your specific purpose; hence the need for programming skills.

Q2.6: What’s the story with the different randomizations mentioned on some of the forms?

Some of the forms allow you to choose between three different types of randomization. If you’re not sure what to choose, you almost certainly want to ‘generate your own personal randomization right now,’ which is the first (and default) option. In this mode, your numbers (or strings or whatever) will be generated based on true randomness created especially for you and which will be discarded immediately after it has been used. There is no way to predict what these numbers will be, and there is no way to recreate the same numbers later. This is the standard way of using a true random number generator.

The other two modes allow you to select a pregenerated randomization, which means that your numbers or strings will be based on randomness generated by RANDOM.ORG some time in the past. These modes allows you to replay a given sequence of numbers at a later stage, and allows multiple parties in different locations to get the same numbers in a predictable fashion. These modes effectively turn RANDOM.ORG into a pseudo-random number generator.

Q2.7: Which probability distributions are supported?

Currently, the generators support only the discrete uniform distribution. The only exception is the Gaussian Generator, which supports theGaussian distribution (also known as the normal distribution). No other distributions are currently supported. If you would like to see other distributions, email us the details and we may choose to include them in the future.