<PAGE>

                                                                     EXHIBIT 4.6

                                     FORM OF
                             STOCK OPTION AGREEMENT
                            FOR CLASS B COMMON STOCK

         This STOCK OPTION AGREEMENT (this "Agreement") is entered into as of
____________, ____, by and between IDT Corporation, a Delaware corporation (the
"Company"), and ____________ (the "Employee").

         WHEREAS, the Company desires to grant to the Employee options to
acquire an aggregate of ____ shares of Class B Common Stock of the Company, par
value $.01 per share (the "Stock"), on the terms set forth herein.

         NOW, THEREFORE, the parties hereby agree as follows:

         1. Definitions. Capitalized terms are defined herein.

         2. Grant of Options. The Employee is hereby granted stock options (the
"Options") to purchase an aggregate of ____ shares of Stock, pursuant to the
terms of this Agreement.

         3. Term. The term of the Options (the "Option Term") shall be for ten
(10) years commencing on _____ _____, _____ and terminating on _____ ____,
_____.

         4. Option Price. The initial exercise price per share of the Options
shall be $____.____, subject to the adjustment as provided herein.

         5. Conditions to Exercisability. The Options shall vest and become
exercisable on ____ _____, _____ if the Employee continues to be employed by or
acts as a Consultant to or a Director of the Company or any of its subsidiaries
on such date.

         6. Method of Exercise. An Option may be exercised, as to any or all
full shares of the Stock as to which the Option has become exercisable, by
written notice delivered in person or by mail to the Company's transfer agent or
other administrator designated by the Company, specifying the number of shares
of Stock with respect to which the Option is being exercised.

         7. Medium and Time of Payment. The Option Price shall be paid un full,
at the time of exercise, in cash or in shares of Stock (whether then owned by
the Employee or issuable upon exercise of the Option) having a Fair Market Value
equal to such Option Price or in a combination of cash and Stock, including a
cashless exercise procedure through a broker-dealer.

         8. Termination. Except as provided in this Section 8 and in Section 9
hereof, an Option may not be exercised unless the Employee is then in the employ
of or maintaining a director or consultant relationship with the Company or a
Subsidiary thereof (or a company or Parent or Subsidiary of such company issuing
or assuming the Option in a transaction to which Section 424(a) of the Code
applies), and unless the Employee has remained continuously so employed or in
the director or consultant relationship since the date of grant of the Option.
In the event that the employment or consultant relationship of a Employee shall
terminate (other than by reason of death, Disability or Retirement), all Options
of such Employee that are exercisable at the time of Employee's termination may,
unless earlier terminated in accordance with their terms, be exercised within
three (3) months after the date of such termination (or such different period as
the Compensation Committee of the Company (the "Committee") shall prescribe).

         9. Death, Disability or Retirement of Employee. If the Employee shall
die while employed by, or maintaining a director or consultant relationship
with, the Company or a Subsidiary thereof, or within thirty (30) days after the
date of termination of such Employee's employment, director or consultant
relationship (or within such different period as the Committee may have provided

<PAGE>

pursuant to Section 8 hereof), or if the Employee's employment, director or
consultant relationship shall terminate by reason of Disability, all Options
theretofore granted to the Employee (to the extent otherwise exercisable) may,
unless earlier terminated in accordance with their terms, be exercised by the
Employee or by the Employee's estate or by a person who acquired the right to
exercise such Options by bequest or inheritance or otherwise by result of death
or Disability of the Employee, at any time within 180 days after the death or
Disability of the Employee (or such different period as the Committee shall
prescribe). In the event that an Option granted hereunder shall be exercised by
the legal representatives of a deceased or former Employee, written notice of
such exercise shall be accompanied by a certified copy of letters testamentary
or equivalent proof of the right of such legal representative to exercise such
Option. In the event that the employment or consultant relationship of a
Employee shall terminate on account of such Employee's Retirement, all Options
of the Employee that are exercisable at the time of such Retirement may, unless
earlier terminated in accordance with their terms, be exercised at any time
within one hundred eighty (180) days after the date of such Retirement (or such
different period as the Committee shall prescribe).

         10. Withholding Taxes. No later that the date of exercise of any
Option, the Employee will pay to the Company or make arrangements satisfactory
to the Company regarding payment of any federal, state or local taxes of any
kind required by law to be withheld upon the exercise of an Option.
Alternatively, solely to the extent permitted or required by law, the Company
may deduct the amount of any federal, state or local taxes of any kind required
by law to be withheld upon the exercise of an Option from any payment of any
kind due to the Employee. The withholding obligation may be satisfied by the
withholding or delivery of the Stock.

         11. Terms Incorporated by Reference Herein. Each of the terms of the
Company's 1996 Stock Option and Incentive Plan, as Amended and Restated
("Plan"), as in effect as of the date hereof, shall be deemed to govern the
Options granted hereunder, as if the Options had been granted pursuant to the
Plan. To the extent that there is any inconsistency between this Agreement and
the terms of the Plan, the terms of this Agreement shall govern.

         12. Transferability of Options. Stock Options may not be sold, pledged,
assigned, hypothecated, transferred or disposed of in any manner other than to
an immediate family member of Employee or to a trust or other estate planning
entity created for the benefit of the Employee or one or more members of his
immediate family as provided for under the Plan, provided that, in all cases,
such transferee executes a written consent to be bound by the terms of this
Agreement.

         13. Entire Agreement. This Agreement contains all of the understandings
between the parties hereto pertaining to the matters referred to herein, and
supersedes all undertaking and agreement, whether oral or in writing, previously
entered into by them with respect thereto. The Employee represents that, in
executing this Agreement, he does not rely and has not relied upon any
representation or statement not set forth herein made by the Company with regard
to the subject matter of this Agreement or otherwise.

         14. Amendment or Modification, Waiver. No provision of this Agreement
may be amended or waived unless such amendment or waiver is agreed to in
writing, signed by the Employee and by a duly authorized officer of the Company.
No waiver by any party hereto of any breach by another party hereto of any
condition or provision of this Agreement to be performed by such other party
shall be deemed a waiver of a similar of dissimilar condition or provision at
the same time, any prior time or any subsequent time.

         15. Notices. Each notice relating to this Agreement shall be in writing
and delivered in person or by certified mail to the proper address. All notices
to the Company shall be addressed to it at:

             IDT Corporation
             520 Broad Street
             Newark, New Jersey 07102
             Attention: Shari Gordon
                        Options Administrator

         All notices to the Employee or other person or persons then entitled to
exercise the Options shall be addressed to the Employee or such other person or
persons at:

         -------------------------

         -------------------------

         -------------------------
<PAGE>

         Anyone to whom a notice may be given under this Agreement may designate
a new address by notice to such effect.

         16. Severability. If any provisions of this Agreement or the
application of any such provision to any party or circumstances shall be
determined by any court of competent jurisdiction to be invalid and
unenforceable to any extent, the remainder of this Agreement or the application
of such provision to such person or circumstances other than those to which it
is so determined to be invalid and unenforceable, shall not be effected thereby,
and each provision hereof shall be validated and shall be enforced to the
fullest extent permitted by law.

         17. Governing Law. This Agreement shall be construed and governed in
accordance with the laws of the state of Delaware, without regard to principles
of conflicts of laws.

         18. Headings. All descriptive headings of sections and paragraphs in
this Agreement are intended solely for convenience, and no provision of this
Agreement is to be construed by reference to the heading of any section or
paragraph.

         19. Counterparts. This Agreement may be executed in counterparts, each
of which shall be deemed to be an original but both of which together shall
constitute one and the same instrument.

         IN WITNESS WHEREOF, the Company has caused this Agreement to be
executed by an authorized officer and the Employee has hereunto set his hand all
as of the date first above written.

                                           IDT Corporation


                                           By:
                                              ----------------------------------
                                              Name:
                                              Title:


                                           By:
                                              ----------------------------------
                                              Name:
                                              Title:

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                             Schedule to Exhibit 4.6

Attached to this Schedule is a Form of Stock Option Agreement by and between IDT
Corporation and each of the optionees listed in note (7) to the "Calculation of
Registration Fee" table in the Registration Statement to which this Schedule and
Exhibit are attached. The executed Stock Option Agreements are substantially
identical to the Form of Stock Option Agreement attached to this Schedule except
as to the dates of execution, the names of the optionees, the optionees'
respective addresses, the number of shares of Class B Common Stock of IDT
Corporation underlying the options reflected thereby, the exercise prices for
such shares and the vesting periods applicable to such options. The number of
shares of Class B Common Stock underlying such options ranges from 500 to
180,000, the exercise prices range from $20.875 to $31.625 and the options vest
in tranches over periods ranging from one to three years. Set forth below are
the dates of execution, number of shares of Class B Common Stock underlying the
options, exercise prices and vesting periods with respect to such Option
Agreements entered into with executive officers of IDT Corporation:

<TABLE>
<CAPTION>
-------------------- --------------- ----------------------- -------------------- ----------------------------------
 Name of Optionee    Date of Stock         Number of           Exercise Price                  Vesting
                         Option            Shares of
                       Agreement      Class B Common Stock
                                             of IDT
                                      Corporation Issuable
                                        Upon Exercise of
                                             Option
-------------------- --------------- ----------------------- -------------------- ----------------------------------
<S>                     <C>                <C>                   <C>              <C>
Hal Brecher             2/1/2000             50,000                $20.875        8,500 8/1/00, 8,300 2/1/01,
                                                                                  8,300 8/1/01, 8,300 2/1/02,
                                                                                  8,300 8/1/02, 8,300 2/1/03
-------------------- --------------- ----------------------- -------------------- ----------------------------------
Stephen Brown           2/1/2000            120,000                $20.875        20,000 8/1/00, 20,000 2/1/01,
                                                                                  20,000 8/1/01, 20,000 2/1/02,
                                                                                  20,000 8/1/02, 20,000 2/1/03
-------------------- --------------- ----------------------- -------------------- ----------------------------------
James Courter           2/1/2000             50,000                $20.875        8,500 8/1/00, 8,300 2/1/01,
                                                                                  8,300 8/1/01, 8,300 2/1/02,
                                                                                  8,300 8/1/02, 8,300 2/1/03
-------------------- --------------- ----------------------- -------------------- ----------------------------------
Michael Fischberger     2/1/2000            120,000                $20.875        20,000 8/1/00, 20,000 2/1/01,
                                                                                  20,000 8/1/01, 20,000 2/1/02,
                                                                                  20,000 8/1/02, 20,000 2/1/03
-------------------- --------------- ----------------------- -------------------- ----------------------------------
Moshe Kaganoff          2/1/2000             80,000                $20.875        15,000 8/1/00, 13,000 2/1/01,
                                                                                  13,000 8/1/01, 13,000 2/1/02,
                                                                                  13,000 8/1/02, 13,000 2/1/03
-------------------- --------------- ----------------------- -------------------- ----------------------------------
Marc Knoller            2/1/2000             50,000                $20.875        8,500 8/1/00, 8,300 2/1/01,
                                                                                  8,300 8/1/01, 8,300 2/1/02,
                                                                                  8,300 8/1/02, 8,300 2/1/03
-------------------- --------------- ----------------------- -------------------- ----------------------------------
Morris Lichtenstein     2/1/2000            180,000                $20.875        30,000 8/1/00, 30,000 2/1/01,
                                                                                  30,000 8/1/01, 30,000 2/1/02,
                                                                                  30,000 8/1/02, 30,000 2/1/03
-------------------- --------------- ----------------------- -------------------- ----------------------------------
Joyce Mason             2/1/2000             50,000                $20.875        8,500 8/1/00, 8,300 2/1/01,
                                                                                  8,300 8/1/01, 8,300 2/1/02,
                                                                                  8,300 8/1/02, 8,300 2/1/03
-------------------- --------------- ----------------------- -------------------- ----------------------------------
Geoffrey Rochwarger     2/1/2000            120,000                $20.875        20,000 8/1/00, 20,000 2/1/01,
                                                                                  20,000 8/1/01, 20,000 2/1/02,
                                                                                  20,000 8/1/02, 20,000 2/1/03
-------------------- --------------- ----------------------- -------------------- ----------------------------------
</TABLE>