Elsinore Union Elementary School Dist. V. Kastoroff 54 Cal.2d 380, 6 Cal.Rptr. 1, 353 P.2d 713 (Cal 1960) Kastoroff was a contractor that bid to add an addition to an Elsinore school.  As part of the bidding process, Kastoroff made a math error in calculating his costs and wound up significantly underbidding the project.  Since he was by far the low bidder, Elsinore awarded him the contract. Kasteroff wrote the school board informing them of his error and asking them to remove his bid.  The school board refused at first but eventually relented. The school board hired another contractor at a higher price, and then sued Kasteroff to recover the difference. The school board sought to cover for breach of contract, and to mitigate damages. The Trial Court found for Elsinore. The Appellate Court reversed the decision. The Appellate Court noted that the case of M.F. Kemper Constr. Co. v. City of Los Angeles was very similar, and that case held that a contractor making a clerical error in computing a bid on a public work is entitled to rescind that bid. The error needs to be an excusable and honest mistake.  If you made a mistake because you were negligent in your calculations, the contract would still be enforceable. The bid was not so low that it was a palpable mistake. Palpable mistakes are obvious to all sides (like if Kastoroff had bid $9 instead of $90k). Courts have almost universally held that parties can get out of contracts that have palpable mistakes. Since Elsinore had not suffered any damages, to require Kasteroff to perform for the mistaken amount would be unconscionable. There is no useful social purpose served by enforcing mistaken terms. The Court suggests three factors that helped Kastoroff win, even though the error was not palpable. Plaintiff reports the error promptly. The error was not so large as to be a burden on the other party. Contracts with public entities are more forgiving than those with private companies.