import type { BudgetPeriod } from '../types/lifecycle.js';
/** The start of the period `at` falls in, as epoch milliseconds, in UTC. */
export declare function periodStart(period: BudgetPeriod, at: Date): number;
/** When the period `at` falls in ends, as epoch milliseconds. */
export declare function periodEnd(period: BudgetPeriod, at: Date): number;
/** The period in words, for an error message. */
export declare function describePeriod(period: BudgetPeriod): string;