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: 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 AmberTools23
conda activate AmberTools23
(Note that you would need to perform the "conda activate" step every
you wish use AmberTools23 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 for spearheading this.
Option 2: Upgrading from an AmberTools22 source code installation
If you already have an AmberTools22 source code installation, do this:
Then follow the instructions to re-build the installation.
Option 3: Getting source code in tar format
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
To download version
23 of the AmberTools distribution, please fill in the following
form and click the "Download" button. The file size you should get is
about 543 MB, and the
Note: Installation instructions are in Chapter 2 of the
Amber 2023 Reference
Manual. More detailed instructions for many systems may be found at
OS-specific requirements page.
How to obtain Amber22
Amber22 facilitates faster simulations (on parallel CPU or GPU hardware)
and is distributed with a separate license and fee structure. Here is the
AMBER22 Software License
GRANT OF LICENSE. The Regents of the University of California grants, and you
hereby accept, a permanent, non-exclusive license to use the Amber 22 software product
("Software") to the extent of its rights and in accordance with the terms of
this Agreement. This licensed copy of the Software may only be used by you
and members of your organization at your site who have read and agreed to
this license. You may install the Software on computers at your site, or at
other locations, provided that reasonable steps are taken to restrict use of
the software to you and members of your organization. You may not distribute
copies of the Software to others outside of your organization, and may make
only those copies of the Software which are necessary to install and use it
as permitted by this Agreement, or are for purposes of backup and archival
This ownership is protected by the copyright
laws of the United States and by international treaty provisions. Upon
expiration or termination of this Agreement, you shall promptly terminate
use of the Software and accompanying written materials.
MODIFICATIONS AND DERIVATIVE WORKS. You may modify the software, and use it to
create derivative works, for your internal use at the site covered by this
license. You may not distribute such modified or derivative software to
others outside of your site without written permission. You may distribute
the modifications themselves (e.g. as "patches") under terms of your choice.
We encourage users to contribute modifications back into Amber, but you are
under no obligation to do so.
ASSIGNMENT RESTRICTIONS. You shall not use the Software (or any part thereof)
in connection with the provision of consultancy, modeling or other services,
whether for value or otherwise, on behalf of any third party who does not
hold a current valid Amber 22 Software License Agreement. You shall not
rent, lease, or otherwise sublet the Software or any part thereof. You may
transfer on a permanent basis the rights granted under this license provided
you transfer this Agreement and all copies of the Software, including prior
versions, and all accompanying written materials. The recipient must agree
to the terms of this Agreement in full and register this transfer with the
University of California.
LICENSEE acknowledges that LICENSORS make no warranty,
expressed or implied, that the program will function without error, or in any
particular hardware environment, or so as to generate any particular
function or result, and further excluding any other warranty, as to the
condition of the program, its merchantability, or its fitness for a particular
purpose. LICENSORS shall not be liable for any direct, consequential, or other
damages suffered by the LICENSEE or any others as a result of their use of the
program, whether or not the same could have been foreseen by LICENSORS prior
to granting this License. In no event shall LICENSORS liability for any breach
of this agreement exceed the fee paid for the license.
UNIVERSITY OF CALIFORNIA'S LIABILITY. In no event shall the University of
California be liable for any indirect, special, or consequential damages, such
as, but not limited to, loss of anticipated profits or other economic loss
in connection with or arising out of the use of the software by you or the
services provided for in this Agreement, even if the University of California
has been advised of the possibility of such damages. The University of
California's entire liability and your exclusive remedy shall be, at the
University of California's discretion, to return the Software and proof of
purchase to the University of California for either (a) return of any license
fee, or (b) correction or replacement of Software that does not meet the terms
of this limited warranty.
NO OTHER WARRANTIES. The University of California disclaims other implied
warranties, including, but not limited to, implied warranties of
merchantability or fitness for any purpose, and implied warranties arising
by usage of trade, course of dealing, or course of performance. Some states
do not allow the limitation of the duration or liability of implied
warranties, so the above restrictions might not apply to you.
Getting Amber22 for non-commerical use
Read the above license: note it contains restrictions on usage
By filling out this form, you agree to the license, and confirm that all
use will be non-commerical. Note that there is no license fee for
Please note: You must also download and untar AmberTools23
using options 2 or 3, as described above.
Getting Amber22 for commerical use
The license above is valid for both commerical and non-commerical usage.
Only the license fee is different from commerical use.
Commerical users should fill out this
for a commerical license. This will generate a license form that you
can sign, and will contain information about how to pay the license fee.
Once payment is received, an email will be sent to the address you
provide, containing a username and password, along with instructions on how
to download the software.
Please note: The Amber22 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.)
Basically, the license deals with the affiliation of the users, and not with
the location of the computing equipment itself.
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: $0. Use the
"non-commerical" form, above.
- Industrial (for-profit): $25,000 for new licensees, $20,000
for licensees of Amber 18 or Amber20.
- Porting and demonstration licenses are available, as are
licenses for computing centers: see the
License Agreement for
- Users who
license Amber22 after January 1, 2024 are eligible for a free upgrade to
Amber24 upon its release. (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.)