How to obtain AmberTools21
AmberTools is a free, useful standalone package and a prerequisite for
installing Amber itself.
The AmberTools suite is free of charge, and its components are mostly
released under the GNU General Public License (GPL). A few components are
included that are in the public domain or which have other, open-source,
licenses. The libsander and libpbsa libraries use the LGPL license.
Option 1: Upgrading from AmberTools20
If you already have AmberTools20 installed from source, just do
Option 2: Binary distribution via conda
The conda package-management system can
install a serial, binary (pre-compiled) distribution.
This should work for Linux and MacOS systems, and may be
sufficient for many users.
It provides a simple way to get started with
AmberTools, and to install it into many workflows. It does not provide
access to parallel or GPU-enabled options, and the
full source-code distributions are needed if you wish to
combine AmberTools with Amber.
To install, proceed as follows:
If you don't have conda installed, please visit the
Those with an existing conda installation may wish to create a
new conda "environment" to avoid conflicts with what you already have
installed. To do this:
conda create --name AmberTools21
conda activate AmberTools21
(Note that you would need to perform the "conda activate" step every
you wish use AmberTools21 in a new terminal; it might be appropriate to
add this to your start-up script. Creating a new environment should not
be necessary if you only use conda for AmberTools.)
Once this is done, type:
conda install -c conda-forge
AmberTools is updated from time to time. To keep your conda
package up-to-date, do this:
conda update -c conda-forge
Thanks to Jaime Rodríguez-Guerra, the Chodera lab, and Simon Bray
for spearheading this.
Option 3: Getting source code in tar format
This path is for users to do not already have AmberTools20, and
is the traditional way AmberTools has been distributed.
AmberTools is distributed in source code format, and must be compiled in
order to be used. You will need C, C++ and Fortran90
The Reference Manual is available
in pdf format, and included in the distribution. It may help you to
see if AmberTools meets your needs.
To download version
21 of the AmberTools distribution, please fill in the following
form and click the "Download" button. The file size you should get is
about 500 MB, and the
Note: Installation instructions are in Chapter 2 of the
Amber 2021 Reference
Manual. More detailed instructions for many machines may be found at
simplified requirements for MacOS, Linux and
How to obtain Amber20
Amber20 facilitates faster simulations (on parallel CPU or GPU hardware)
and is distributed with a separate license and fee structure.
Click here for the
Amber 20 License Agreement (PDF).
Print this form, fill it out, sign and return (with your payment) to the
address given at the bottom of the license agreement. Once your order is
processed, you will receive download information via email. PDF versions of
the Reference Manual are included in the download.
Please note: The Amber20 license is a site license, valid for any
number of users and any number of computers. The computers may be located
anywhere (such as in the "cloud", or at remote computing centers.) There are
restrictions on using the codes on behalf of others who do not have an Amber
license; see the license document for details.
Also note: Each release of Amber (which happens every two years) is
treated as separate product, and requires a new license form and a new fee.
- Academic/non-profit/government: $500 (US dollars).
- Industrial (for-profit): $20,000 for new licensees, $15,000
for licensees of Amber 18.
- Porting and demonstration licenses are available, as are
licenses for computing centers: see the
License Agreement for
- Custom payment schedules or subscription-based approaches can be arranged:
please send email to
for more information.)
- People who
licensed Amber18 after January 1, 2020 are eligible for a free upgrade to
Amber20. (This is not automatic: if you wish to obtain
the new version, you need fill out and submit a new License Agreement,
indicating that you are eligible for the upgrade.)
Payment for all orders for Amber must received prior to
shipment of the Software. Payment must be via
bank transfer, paper bank check or paper money order in USD, or Visa,
or American Express credit card. Make payments to: Regents, University of
California. We are sorry, but purchase orders can no longer be accepted.
Once payment is received, an email will be sent to the address provided by
the customer on the License Agreement
containing a username and password, along with instructions on how to
download the software.
Waivers for the license fee are available for scientists outside of
North America, Western Europe and Japan. Please send email to
firstname.lastname@example.org, explaining your situation, and your need
for the pmemd program (all other parts of Amber are available for