Campaigning for governor, lieutenant governor and attorney general of Virginia will cost more than ever this year - perhaps as much as $5 million.

But because of the large number of candidates - a dozen are competing for their shares of the money - and inflation, this year's campaigns may have to be more thrifty than those waged in 1973 and 1969.

The estimated $5 million total, the result of interviews with campaign officials, would easily set a record for state office campaign funding in Virginia in one year.

The most expensive race, of course, is the contest between Democrats Henry E. Howell and Andrew P. Miller and Republican John N. Dalton for governor.

Former Attorney General Miller hopes to raise $1 million for his primary race against former Lt. Gov. Howell, who is hoping to raise and spend about $650,000.

The winner of the Democratic primary is expected to spend enough in the general election to raise his total campaign cost to $1.5 million. Dalton has set a budget goal of $1.3 million.

This adds up to about $3.5 million for the gubernatorial election, including the Democratic primary, or almost $2 for every vote that would be cast in moderate turnouts.

In 1973, Republican Gov. Mills E. Godwin and Howell, running as an independent, each spent about $1 million in their general election contest, also about $2 for each vote cast. There were no primary contests four years ago.

Virginia campaign managers all agree that the cost of running for office has grown much faster in the last four years than is indicated by their budgets. "We will compensate for inflation by getting more mileage out of each campaign dollar than either Howell or Godwin did," Dalton campaign director William A. Royall said in an interview.

There is no universally accepted standard for judging whether campaign spending is reasonable or excessive, but the projected gubernatorial budgets are close to spending ceilings proposed in federal legislation for U.S. Senate races in Virginia.

A bill introduces in the U.S. Senate would provide public funding to Senate candidates who hold total spending within specified limits. For Virginia, the limit for a Senate race would be about $1.2 million for a primary and general election. This total is derived by applying a primary spending limit of 15 cents for each of the state's estimated 3.5 million voting-age residents.

The three gubernatorial campaigns are pursuing donors with distinctly different fund-raising styles.

The Miller campaign has built its fund-raising efforts around an unusually large finance committee of 400 persons that campaign manager Walter Marston describes "mostly middleechelon business and professional people."

"Each committee member is responsible for raising at least $2,000," Marston said. This would account for more than half of Miller's financing.

Howell, making his third race for the governor's office in eight years, said in an interview that for major contributions he is relying on personal appeals to past supporters and a staff fund raising by William Rosendahl. Rosendahl is an experienced presidential campaign worker who was a fund raiser for Sen. George McGovern (D-S.D.) in his unsuccessful 1972 presidential race.

Dalton's appeal for major contributions is being made by a finance committee headed by Richmond investment banker Walter M. Craigie Jr., a veteran Republican fund raiser and secretary of finance in the administration of former Gov. Linwood Holton.

All three campaigns expect the majority of their funds, perhaps 60 per cent, to come from donations of $100 or more. The Dalton campaign, in fact, has projected that more than half of its donations will come from about 300 persons giving $1,000 or more.

Despite this open targeting of big givers, Dalton manager Royall insisted, "I predict that we will end up with more contributors and a smaller average contribution than either Howell or Miller."

The Dalton campaign is counting on an effective direct mail campaign to bring in 10,000 small gifts averaging only $20 each. Neither Howell nor Miller is planning an ambitious direct mail solicitation.

The vigorous fund-raising efforts of the gubernatorial candidates, campaign managers agree, is making it hard for candidates for lieutenant governor and attorney general to mount effective fund-raising drives.

Nevertheless, two of the three Democratic candidates for lieitenant governor - Del. Richard S. (Major) Reynolds (D-Richmond) and Charles S. (Chuck) Robb of McLean - are considered likely to spend more in seeking that office than has ever been spent before - perhaps as much as $300,000 in the primary and $200,000 more by the winner for the general election.

Reynolds is a member of the Reynolds Metals family and Robb is the son-in-law of the late Preshe late President Lyndon B. Johnson.

In the attorney general race, only Del. Edward E. Lane (D-Richmond) is considered to have the potential to run a heavily financed primary campaign because of his close ties to the Richmond financial community.

The first disclosure of campaign gifts and spending will not be made until May 14, 30 days before the Democratic primary. Another report must be filed seven days before the election and gifts of more than $1,000 must be reported during the last week before the voting.