Can I use the annualized income method to lower estimated taxes on a seasonal business?

Yes, and it can save real money if your income is lumpy. Instead of paying equal quarterly installments, the annualized income installment method lets you base each payment on what you actually earned in that period. So if most of your revenue arrives in the fourth quarter, you pay little early and more later, matching cash flow and avoiding penalties for the light quarters. You report it on Form 2210, Schedule AI, at tax time. The tradeoff is heavier bookkeeping, since you must calculate year-to-date income at each deadline. It is ideal for seasonal, commission, or project-based businesses whose earnings would otherwise trigger penalties under the flat-installment default.