Exhibit 99.1

PRESS RELEASE

INVESTOR CONTACT:

Lisa L. Ewbank

Synopsys, Inc.

650-584-1901

Synopsys-ir@synopsys.com

EDITORIAL CONTACT:

Simone Souza

Synopsys, Inc.

650-584-6454

simone@synopsys.com

Synopsys Posts Financial Results for Fourth Quarter and Fiscal Year 2018

Q4 2018 Financial Highlights

FY 2018 Financial Highlights

MOUNTAIN VIEW, Calif. – Dec. 5, 2018 – Synopsys, Inc. (Nasdaq: SNPS) today reported results for its fourth quarter and fiscal year 2018. Revenue for the fourth quarter was $795.1 million, compared to $696.6 million for the fourth quarter of fiscal 2017. Revenue for fiscal year 2018 was $3.121 billion, an increase of 14.5 percent from $2.725 billion in fiscal year 2017.

“Fiscal 2018 was another excellent year for Synopsys. We delivered double-digit revenue and earnings growth, with strength across all product groups and all geographies,” said Aart de Geus, chairman and co-CEO of Synopsys. “Notwithstanding expectations of more modest semiconductor industry growth in 2019, design activity across the Silicon to Software spectrum continues unabated. Over the past five years we’ve made significant investments in developing next-generation EDA platforms, elevating the impact of our IP portfolio, and diversifying into an exciting new software security and quality market. As we look to our next phase of growth to

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$4 billion in revenue and beyond, we are raising our long-term financial objectives. Our objective is to drive annual double-digit non-GAAP earnings per share growth, through a mix of continued solid revenue growth and expansion of non-GAAP operating margins to the high 20s over time, with a goal of ~26% in 2021.”

GAAP Results

On a generally accepted accounting principles (GAAP) basis, net income for the fourth quarter of fiscal 2018 was $254.3 million, or $1.66 per share, compared to net loss of $120.1 million, or $(0.80) per share, for the fourth quarter of fiscal 2017. GAAP net income for fiscal year 2018 was $432.5 million, or $2.82 per share, compared to $136.6 million, or $0.88 per share, for fiscal year 2017.

Non-GAAP Results

On a non-GAAP basis, net income for the fourth quarter of fiscal 2018 was $119.6 million, or $0.78 per share, compared to non-GAAP net income of $106.5 million, or $0.69 per share, for the fourth quarter of fiscal 2017. Non-GAAP net income for fiscal year 2018 was $599.7 million, or $3.91 per share, compared to non-GAAP net income of $529.1 million, or $3.42 per share, for fiscal year 2017. Reconciliation between GAAP and non-GAAP results is provided later in this press release.

Financial Targets

Synopsys also provided its financial targets for the first quarter and full fiscal year 2019, which do not include any impact of future acquisition-related activities or costs. These targets constitute forward-looking statements and are based on current expectations. For a discussion of factors that could cause actual results to differ materially from these targets, see “Forward-Looking Statements” below.

Synopsys will adopt new revenue recognition requirements under ASC 606, “Revenue from Contracts with Customers,” in the first fiscal quarter of 2019. Using the modified retrospective method, the cumulative effect of initially applying the new recognition standards is recognized at the date of initial application. Revenue during the fiscal 2019 transition year is estimated to be approximately $40 million lower under ASC 606 than it would be under ASC 605, “Revenue Recognition,” and the impact is expected to decline to roughly neutral within two years.

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Throughout the 2019 transition year, actual results will be presented under both ASC 606 and ASC 605 revenue recognition rules. Synopsys is providing both official targets under ASC 606 and comparable numbers under ASC 605 for ease of comparison to prior periods. Additional details are available in the financial supplement on Synopsys’ corporate website.

First Quarter and Fiscal Year 2019 Financial Targets – ASC 606

(in millions except per share amounts)

For reference, below are key comparative metrics under ASC 605 rules.

Earnings Call Open to Investors

Synopsys will hold a conference call for financial analysts and investors today at 2:00 p.m. Pacific Time. A live webcast of the call will be available on Synopsys’ corporate website at www.synopsys.com. A recording of the call will be available by calling +1-800-475-6701 (+1-320-365-3844 for international callers), access code 456657, beginning at 4:00 p.m. Pacific Time today, until 11:59 p.m. Pacific Time on December 12, 2018. A webcast replay will also be available on the website from approximately 5:30 p.m. Pacific Time today through the time Synopsys announces its results for the first quarter of fiscal year 2019 in February 2019. Synopsys will post copies of the prepared remarks of Aart de Geus, chairman and co-chief executive officer, and Trac Pham, chief financial officer, on its website following today’s call. In addition, Synopsys makes additional information available in a financial supplement and corporate overview presentation, also posted on the corporate website.

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Effectiveness of Information

The targets included in this press release, the statements made during the earnings conference call and the information contained in the financial supplement and corporate overview presentation (available in the Investor Relations section of Synopsys’ corporate website at www.synopsys.com) represent Synopsys’ expectations and beliefs as of the date of this release only. Although this press release, copies of the prepared remarks of the co-chief executive officer and chief financial officer made during the call, the financial supplement, and the corporate overview presentation will remain available on Synopsys’ website through the date of the first quarter of fiscal year 2019 earnings call in February 2019, their continued availability through such date does not mean that Synopsys is reaffirming or confirming their continued validity. Synopsys does not currently intend to report on its progress during the first quarter of fiscal year 2019 or comment to analysts or investors on, or otherwise update, the targets given in this release.

Availability of Final Financial Statements

Synopsys will include final financial statements for fiscal year 2018 in its annual report on Form 10-K to be filed by January 2, 2019.

About Synopsys

Synopsys, Inc. (Nasdaq: SNPS) is the Silicon to Software™ partner for innovative companies developing the electronic products and software applications we rely on every day. As the world’s 15th largest software company, Synopsys has a long history of being a global leader in electronic design automation (EDA) and semiconductor IP and is also growing its leadership in software security and quality solutions. Whether you’re a system-on-chip (SoC) designer creating advanced semiconductors, or a software developer writing applications that require the highest security and quality, Synopsys has the solutions needed to deliver innovative, high-quality, secure products. Learn more at www.synopsys.com.

GAAP to Non-GAAP Reconciliation

Synopsys continues to provide all information required in accordance with GAAP but believes evaluating its ongoing operating results may not be as useful if an investor is limited to reviewing only GAAP financial measures. Accordingly, Synopsys presents non-GAAP financial

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measures in reporting its financial results to provide investors with an additional tool to evaluate Synopsys’ operating results in a manner that focuses on what Synopsys believes to be its core business operations and what Synopsys uses to evaluate its business operations and for internal planning and forecasting purposes. Synopsys’ management does not itself, nor does it suggest that investors should, consider such non-GAAP financial measures in isolation from, or as a substitute for, financial information prepared in accordance with GAAP. Synopsys’ management believes it is useful for itself and investors to review, as applicable, both GAAP information that includes: (i) the amortization of acquired intangible assets, (ii) the impact of stock compensation, (iii) acquisition-related costs, (iv) restructuring charges, (v) the effects of certain settlements, final judgments and loss contingencies related to legal proceedings, (vi) the various income tax impacts prompted by the Tax Cut and Jobs Act of 2017 enacted on December 22, 2017 (“U.S. Tax Reform”), including the income tax related to transition tax, the tax rate change, and tax restructuring, (vii) the tax impact of repatriation, and (viii) the income tax effect of non-GAAP pre-tax adjustments; and the non-GAAP measures that exclude such information in order to assess the performance of Synopsys’ business and for planning and forecasting in subsequent periods.

Synopsys utilizes a normalized annual non-GAAP tax rate in the calculation of its non-GAAP measures to provide better consistency across interim reporting periods by eliminating the effects of non-recurring and period-specific items, which can vary in size and frequency and not necessarily reflect our normal operations, and to more clearly align our tax rate with our expected geographic earnings mix. In projecting this rate, we evaluate our historical and projected mix of U.S. and international profit before tax, excluding the impact of stock-based compensation, the amortization of purchased intangibles and other non-GAAP adjustments described above. We also consider other factors including our current tax structure, our existing tax positions, and expected recurring tax incentives, such as the U.S. federal research and development tax credit. On an annual basis we re-evaluate this rate for significant events that may materially affect our projections and, as a result of U.S. Tax Reform, which lowered the U.S. statutory rate from 35% to 21%, we adjusted our normalized annual non-GAAP tax rate from 19% in fiscal years 2016 and 2017 to 13% for fiscal 2018. We expect our annual non-GAAP tax rate to be 16% in fiscal 2019 based upon our projected normalized non-GAAP annual tax rate through fiscal 2021. We will re-evaluate this rate on an annual basis, but further regulatory guidance regarding specific parts of Tax Reform could materially change our

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projections. Notwithstanding the foregoing, we excluded from the normalized annual non-GAAP tax rate in fiscal year 2017 the impact of $166 million tax expense related to the repatriation of offshore cash and, in fiscal year 2018, certain impacts of U.S. Tax Reform described above, as such events are unusual and infrequent.

Whenever Synopsys uses a non-GAAP financial measure, it provides a reconciliation of the non-GAAP financial measure to the most closely applicable GAAP financial measure. Investors are encouraged to review the related GAAP financial measures and the reconciliation of these non-GAAP financial measures to their most directly comparable GAAP financial measure as detailed below, as well as Item 2.02 of the Current Report on Form 8-K filed on December 6, 2018 for additional information about the measures Synopsys uses to evaluate its core business operations.

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Reconciliation of Fourth Quarter and Fiscal Year 2018 Results

The following tables reconcile the specific items excluded from GAAP in the calculation of non-GAAP net income (loss) and earnings (loss) per share for the periods indicated below.

GAAP to Non-GAAP Reconciliation of Fourth Quarter and Fiscal Year 2018 Results

(unaudited and in thousands, except per share amounts)

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Reconciliation of 2019 Targets – ASC 606

The following tables reconcile the specific items excluded from GAAP in the calculation of non-GAAP targets under ASC 606 for the periods indicated below.

GAAP to Non-GAAP Reconciliation of First Quarter Fiscal Year 2019 Targets ⁽¹⁾

(in thousands, except per share amounts)

GAAP to Non-GAAP Reconciliation of Full Fiscal Year 2019 Targets ⁽¹⁾

(in thousands, except per share amounts)

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Reconciliation of Certain 2019 Comparative Metrics – ASC 605

The following tables reconcile the specific items excluded from GAAP in the calculation of certain ASC 605-based non-GAAP comparative metrics for the periods indicated below.

GAAP to Non-GAAP Reconciliation of ASC 605 Comparative Metrics ⁽¹⁾

(in thousands, except per share amounts)

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Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, including, but not limited to, financial targets for the first quarter and full fiscal year 2019, their comparative metrics under ASC 605, and GAAP to non-GAAP reconciliations of such targets, as well as statements related to our long-term revenue, non-GAAP EPS and non-GAAP operating margin objectives, and the expected impact of ASC 606 on our results. These statements involve known and unknown risks, uncertainties and other factors that could cause actual results to differ materially from those expressed or implied in our forward-looking statements. Accordingly, we caution stockholders and prospective investors not to place undue reliance on these statements. Such risks, uncertainties and factors include, but are not limited to: uncertainty in the growth of the semiconductor and electronics industry; consolidation among our customers and our dependence on a relatively small number of large customers; uncertainty in the global economy; fluctuation of our operating results; increased variability in our revenue due to the adoption of ASC 606; our highly competitive industries and our ability to meet our customers’ demand for innovative technology at lower costs; risks and compliance obligations relating to the global nature of our operations; cybersecurity threats or other security breaches; our ability to protect our proprietary technology; our ability to realize the potential financial or strategic benefits of acquisitions we complete; our ability to carry out our new product and technology initiatives; investments of more resources in research and development than anticipated; increased risks resulting from an increase in sales of our hardware products, including increased variability in upfront revenue; changes in accounting principles or standards; changes in our effective tax rate; liquidity requirements in our U.S. operations; claims that our products infringe on third-party intellectual property rights; litigation; product errors or defects; the ability to obtain licenses to third-party software and intellectual property on reasonable terms or at all; the ability to timely recruit and retain senior management and key employees; the inherent limitations on the effectiveness of our controls and compliance programs; the impairment of our investment portfolio by the deterioration of capital markets; the accuracy of certain assumptions, judgments and estimates that affect amounts reported in our financial statements; and the impact of catastrophic events. More information on potential risks, uncertainties and other factors that could affect Synopsys’ results is included in filings it makes with the Securities and Exchange Commission from time to time, including in the sections entitled “Risk Factors” in its Annual Report on Form 10-K for the fiscal year ended October 31, 2017 and its latest Quarterly Report on Form 10-Q. The information provided herein is as of December 5, 2018. Synopsys undertakes no duty, and does not intend, to update any forward-looking statement, whether as a result of new information, future events or otherwise, unless required by law.

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SYNOPSYS, INC.

Unaudited Consolidated Statements of Operations (1)

(in thousands, except per share amounts)

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SYNOPSYS, INC.

Unaudited Consolidated Balance Sheets (1)

(in thousands, except par value amounts)

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SYNOPSYS, INC.

Unaudited Consolidated Statements of Cash Flows (1)

(in thousands)

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