Yesterday, we reported first quarter net income of $167 million or $1.75 per share.
First quarter net income included special items expenses of $0.02 per share related to closure costs for certain corrugated products facilities and specific costs related to discontinuing paper operations associated with the previously announced conversion of the No.
3 machine at our Jackson, Alabama mill to linerboard.
Excluding the special items, first quarter 2021 net income was $169 million or $1.77 per share compared to the first quarter 2020 net income of $143 million or $1.50 per share.
First quarter net sales were $1.8 billion in 2021 and $1.7 billion in 2020.
Total company EBITDA for the first quarter, excluding special items was $342 million in 2021 and $311 million in 2020.
Excluding the special items, the $0.27 per share increase in first quarter 2021 earnings compared to the first quarter of 2020 was driven primarily by higher volumes for $0.45 and prices and mix $0.31 in the Packaging segment and lower annual outage expenses for $0.12.
The items were partially offset by lower volumes, $0.28, and prices and mix of $0.03 in the Paper segment.
Operating costs were $0.15 per share higher, primarily due to inflation-related increases, particularly in the areas of labor and benefits expenses, and fiber costs and energy.
We also had inflation-related increases in our converting costs, which were $0.02 per share higher.
For the last three quarters, freight and logistics costs have risen and were $0.12 per share higher in the first quarter compared to last year.
We also had other expenses of $0.01 per share.
EBITDA excluding special items in the first quarter of 2021 of $352 million with sales of $1.6 billion resulted in a margin of 22% versus last year's EBITDA of $290 million and sales of $1.5 billion or a 20% margin.
As Mark mentioned, corrugated products and containerboard demand were very strong during the quarter, total volume in our corrugated products plants was up 6.6% versus last year and equal the all-time record for total box shipments that we just set in the fourth quarter of 2020.
Shipments per day were up 8.3% over last year, which set a new first quarter record for us.
Strong domestic demand drove outside sales volume of containerboard 13% above last year's first quarter.
Domestic containerboard and corrugated products prices and mix together were $0.26 per share above the first quarter of 2020 and up $0.52 per share compared to the fourth quarter of 2020 as we continued to implement our November 2020 announced price increases during the quarter and we began the implementation of our announced March increase.
Export containerboard prices were up $0.05 per share versus last year's first quarter and up $0.04 per share compared to the fourth quarter of 2020.
Looking at our Paper segment, EBITDA excluding special items in the first quarter was $16 million with sales of $165 million or a 10% margin compared to the first quarter of 2020's EBITDA of $42 million and sales of $217 million or a 19% margin.
As expected, sales volume was about 22% below last year as we ran only one machine at the Jackson, Alabama mill this quarter versus both machines running in the first quarter of 2020.
First quarter paper prices and mix were almost 3% below last year, however, prices began to move higher in the latter part of the quarter, resulting from the announced paper price increases and averaged 1% higher than fourth quarter 2020 average prices.
3 machine at our Jackson, Alabama mill from paper to linerboard, we have not only avoided the significant cost issues associated with extended paper market downtime, but we've also enhanced our capabilities, as well as the profitability in our Packaging segment.
For the first quarter, we generated cash from operations of $192 million and free cash flow of $107 million.
The primary uses of cash during the quarter included capital expenditures of $85 million and common stock dividends of $95 million.
We ended the quarter with $983 million of cash on hand or $1.1 billion, including marketable securities.
Our liquidity at March 31st was $1.5 billion.
Current plans and scope of work for the scheduled maintenance outages at our containerboard mills has changed and the new total company estimated cost impact for the year is $0.97 per share.
The actual impact in the first quarter was $0.10 per share and the revised estimated impact by quarter for the remainder of the year is now $0.30 per share in the second quarter, $0.16 in the third and $0.41 per share in the fourth quarter.
Also, our capital spending estimate for the year has changed to a range of $650 million to $675 million as we have now announced our plans for the conversion of the No.
3 paper machine at our Jackson Mill to linerboard.
3 machine at Jackson, Alabama, our current plans are to continue running the machine on linerboard as demand wards in a manner similar as to how we ran in the first quarter until the scheduled first phase outage is taken in the second quarter of 2022.
The converted machine is expected to operate at an initial production rate of approximately 75% of its new capacity.
The second phase outage work is planned for mid-2023 with the machine reaching its run rate capacity of 2,000 tons per day by the end of 2023.
1 paper machine at Jackson, Alabama and both machines at our International Falls, Minnesota Mill, which is capable of producing all of Jackson's paper grades.
Looking ahead, as we move from the first and into the second quarter, in our Packaging segment, we expect demand to remain strong and we will continue implementing our previously announced paper price increases.
We also expect export prices to move higher.
In the Paper segment, we expect volumes to be fairly flat with higher average prices and mix as we continue the rollout of our recently announced paper price increase.
The second quarter will be our busiest of the year for planned annual outages in the Packaging segment with work scheduled at four of the mills.
Outage expenses are estimated to be approximately $0.20 per share higher compared in the -- to the first quarter.

Summary:
Yesterday, we reported first quarter net income of $167 million or $1.75 per share.
Excluding the special items, first quarter 2021 net income was $169 million or $1.77 per share compared to the first quarter 2020 net income of $143 million or $1.50 per share.
First quarter net sales were $1.8 billion in 2021 and $1.7 billion in 2020.
Looking ahead, as we move from the first and into the second quarter, in our Packaging segment, we expect demand to remain strong and we will continue implementing our previously announced paper price increases.
We also expect export prices to move higher.
In the Paper segment, we expect volumes to be fairly flat with higher average prices and mix as we continue the rollout of our recently announced paper price increase.
The second quarter will be our busiest of the year for planned annual outages in the Packaging segment with work scheduled at four of the mills.