Citizens of United Kingdom can enter Kazakhstan visa free for up to 30 Days. You only need to purchase a visa if you intend to travel to Kazakhstan for longer than 30 Days.
UK citizens will not require a visa for stays of up to 30 days in Kazakhstan. If you wish to stay longer, you will required to apply for a visa before you arrive. Whether you require a visa or not, the day of arrival will be included in the period of stay, regardless of the time you land in Kazakhstan.