March 26, 2020

Howard N. Morof
Chief Financial Officer
Altair Engineering Inc.
1820 East Big Beaver Road
Troy, MI 48083

       Re: Altair Engineering Inc.
           Form 10-K for the Fiscal Year Ended December 31, 2019
           Filed March 2, 2020
           File No. 001-38263

Dear Mr. Morof:

       We have limited our review of your filing to the financial statements
and related
disclosures and have the following comments. In some of our comments, we may
ask you to
provide us with information so we may better understand your disclosure.

       Please respond to these comments within ten business days by providing
the requested
information or advise us as soon as possible when you will respond. If you do
not believe our
comments apply to your facts and circumstances, please tell us why in your
response.

       After reviewing your response to these comments, we may have additional
comments.

Form 10-K for the Fiscal Year Ended December 31, 2019

Selected Financial Data
Key Metrics, page 41

1.    We note your adjustment for "acquisition related deferred revenue"
included in the non-
      GAAP measure "Modified Adjusted EBITDA" as well as in various non-GAAP
measures
      in your Form 8-K furnished on February 27, 2020. Considering your
deferred revenue
      was adjusted to fair value at the time of acquisition pursuant to GAAP,
please tell us how
      you considered whether these non-GAAP measures that include this
adjustment are
      substituting an individually tailored recognition and measurement method
for a GAAP
      measure. Refer to Question 100.04 of the Non-GAAP Compliance and
Disclosure
      Interpretations and Rule 100(b) of Regulation G.
 Howard N. Morof
Altair Engineering Inc.
March 26, 2020
Page 2
Management's Discussion and Analysis of Financial Condition and Results of
Operations
Foreign currency fluctuations, page 46

2.       Revise to disclose the net effects of currency fluctuations on GAAP
Net Income. Refer to
         Question 102.10 of the Non-GAAP Compliance and Disclosure
Interpretations.
Non-GAAP financial measures , page 56

3.       We note your discussion of Adjusted EBITDA and Modified Adjusted
EBITDA without a
         corresponding discussion of GAAP Net income (loss). Please revise to
include a
         discussion of GAAP Net income (loss) for each period presented. Refer
to Question
         102.10 of the Non-GAAP Compliance and Disclosure Interpretations.
Consolidated Financial Statements
Note 3. Revenue from contracts with customers , page 86

4.       Revise to disclose the aggregate amount of the transaction price
allocated to the
         performance obligations that are unsatisfied as of the end of the
reporting period as well as
         an explanation of when you expect to recognize such revenue. Refer to
ASC 606-10-50-
         13.
5.       We note your disclosure on page 87 that when estimating standalone
selling price you
         "consider all information that is reasonably available." Please tell
us and revise to further
         explain the specific methods, inputs, estimates and assumptions used
in determining the
         standalone selling price. Refer to ASC 606-10-50-20.
       In closing, we remind you that the company and its management are
responsible for the
accuracy and adequacy of their disclosures, notwithstanding any review,
comments, action or
absence of action by the staff.

       You may contact Frank Knapp, Staff Accountant, at (202) 551-3805 or
Christine Dietz,
Senior Staff Accountant, at (202) 551-3408 with any questions.



FirstName LastNameHoward N. Morof                               Sincerely,
Comapany NameAltair Engineering Inc.
                                                                Division of
Corporation Finance
March 26, 2020 Page 2                                           Office of
Technology
FirstName LastName