# Request a future reservation for up to 90 days (in calendar mode)

To reserve TPUs for a specific start time and duration, between 1 and 90 days,
request a future reservation in calendar mode. This mode, powered by
the [Dynamic Workload
Scheduler](https://cloud.google.com/blog/products/compute/introducing-dynamic-workload-scheduler),
lets you check TPU availability up to 120 days in advance and request capacity
based on your schedule. You can request a future reservation in calendar mode
using the Compute Engine API or Google Cloud console. If approved,
Compute Engine automatically creates a reservation for your chosen date and
time. You can then [consume the reservation](https://docs.cloud.google.com/tpu/docs/consume-reservation-compute) by
provisioning TPUs, such as VM instances or MIGs, using the Compute Engine API.
Compute Engine
automatically deletes the reservation, and any TPUs that consume it, at the end
of your reservation period.

Requesting a future reservation for up to 90 days (in calendar mode) is a good
fit for training and experimentation workloads that require precise start times
and have a defined duration.

For more information, see [About future reservation requests in calendar
mode](https://docs.cloud.google.com/compute/docs/instances/future-reservations-calendar-mode-overview).

## View future availability of TPUs

You can view the availability of TPUs 1 to 120 days in advance. For more
information, see [View resources future
availability](https://docs.cloud.google.com/compute/docs/instances/create-future-reservations-calendar-mode#view-availability).

## Create a future reservation request in calendar mode

You can request a future reservation in calendar mode using the Compute Engine
API or Google Cloud console. For more information, see [Create a future reservation
request in calendar
mode](https://docs.cloud.google.com/compute/docs/instances/create-future-reservations-calendar-mode).

## Limitations

Requesting a future reservation in calendar mode for TPUs has the following
limitations:

- You can't modify a future reservation request.
- You must specify a reservation duration with a minimum of 1 day and a maximum of 90 days.
- You can reserve 1, 4, 8, 16, 32, 64, 128, 256, 512, or 1,024 TPU chips per request.
- You can only reserve the following TPU versions:
  - [TPU7x](https://docs.cloud.google.com/tpu/docs/tpu7x)
  - [TPU v6e](https://docs.cloud.google.com/tpu/docs/v6e)
  - [TPU v5p](https://docs.cloud.google.com/tpu/docs/v5p)
- You can reserve TPUs only in specific
  [regions and zones](https://docs.cloud.google.com/tpu/docs/regions-zones).

  **Important:** If TPU chips aren't available in any region after you [view future availability](https://docs.cloud.google.com/compute/docs/instances/create-future-reservations-calendar-mode#view-availability), then contact your account team or the sales team.

## What's next

- [Learn about Cloud TPU reservations](https://docs.cloud.google.com/tpu/docs/about-tpu-reservations)
- [Share a reservation between projects](https://docs.cloud.google.com/tpu/docs/share-reservation)
- After your reservation start date, [consume the reservation](https://docs.cloud.google.com/tpu/docs/consume-reservation-compute)