TransAlta (NYSE: TAC) reported earnings on April 26. Here are the numbers you need to know.

The 10-second takeaway
For the quarter ended March 31 (Q1), TransAlta beat expectations on revenues and beat expectations on earnings per share.

Compared with the prior-year quarter, revenue dropped significantly and GAAP earnings per share contracted significantly.

Margins shrank across the board.

Revenue details
TransAlta logged revenue of $657.3 million. The three analysts polled by S&P Capital IQ expected net sales of $628.0 million on the same basis. GAAP reported sales were 22% lower than the prior-year quarter's $842.2 million.

Source: S&P Capital IQ. Quarterly periods. Dollar amounts in millions. Non-GAAP figures may vary to maintain comparability with estimates.

EPS details
EPS came in at $0.20. The one earnings estimate compiled by S&P Capital IQ averaged $0.19 per share. GAAP EPS of $0.40 for Q1 were 58% lower than the prior-year quarter's $0.95 per share.

Source: S&P Capital IQ. Quarterly periods. Non-GAAP figures may vary to maintain comparability with estimates.

Margin details
For the quarter, gross margin was 47.0%, 1,200 basis points worse than the prior-year quarter. Operating margin was 26.5%, 1,740 basis points worse than the prior-year quarter. Net margin was 14.6%, 1,080 basis points worse than the prior-year quarter.

Looking ahead
Next quarter's average estimate for revenue is $630.6 million. On the bottom line, the average EPS estimate is $0.18.

Next year's average estimate for revenue is $2.61 billion. The average EPS estimate is $1.03.

Investor sentiment
The stock has a five-star rating (out of five) at Motley Fool CAPS, with 73 members out of 78 rating the stock outperform, and five members rating it underperform. Among 18 CAPS All-Star picks (recommendations by the highest-ranked CAPS members), 17 give TransAlta a green thumbs-up, and one give it a red thumbs-down.

Of Wall Street recommendations tracked by S&P Capital IQ, the average opinion on TransAlta is hold, with an average price target of $22.44.