A guide to Apple’s guidance by Philip Elmer-DeWitt @FortuneMagazine April 24, 2012, 12:55 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Source: Siddarth Dalal via Seeking Alpha FORTUNE — When it reports its results for the March quarter this afternoon, Apple AAPL will also release forward-looking statements about the June quarter in the form of three numbers: its guidance for revenue, earnings and gross margin. The numbers Apple issues tend to be laughably conservative; the company always prefers to under- rather than over-promise. Nonetheless its guidance is closely watched. It is the only signal Wall Street will get from Apple management about what to expect in the coming quarter. The numbers also provide a useful tool for making baseline predictions of sales and earnings, as Siddarth Dalal suggests in the chart above. Over the past eight quarters, Apple has exceeded its earnings guidance by an average of 42.4% and its revenue guidance by 17.9%. Applying those percentages to the guidance numbers Apple issued in January (Rev: $32.5 billion; EPS: $8.50) suggests that Apple will report: Revenue: $38.31 billion EPS: $12.10 For what it’s worth, those numbers are higher than Wall Street’s estimates and lower than those offered by our pool of independent analysts: Averages: 44 pros, 23 indies, 6 analysts with best track record Looking forward to the June quarter, analysts have used similar methods to anticipate the guidance Apple will give this afternoon. Using the past 10 quarters as a guide, Bernstein’s Toni Sacconaghi expects Apple to give fiscal Q3 guidance of $37 billion (revenue) and $9+ (EPS). Going back 22 quarters, Piper Jaffray’s Gene Munster predicts that Apple will guide $36.6 billion (revenue) and $8.97 (EPS). Forward-looking statements from Apple that exceed those estimates should be warmly greeted by traders. But given what’s been going on with Apple’s stock price over the past two weeks, who knows how they will react? Below the fold: Munster’s 22-quarter spreadsheets.