The decision
A weekly package repeats 52 times in a typical planning year. A biweekly package repeats 26 times. Multiplying a two-week price by two understates the average calendar-month cost, because the year has more than 24 two-week periods.
What to compare
The calculator converts a weekly package using price × 52 ÷ 12, or a biweekly package using price × 26 ÷ 12. It retains the published package rather than prorating it to fewer hours. The conversion is labelled as an equivalent, not as the supplier's monthly quote.
Before you commit
My Mountain Mover publishes different tiers for core, specialised and expert work. Staffingly's VA offer covers a 45-hour week. If you need fewer hours, request an alternative quote; do not assume an unused portion creates a refund or a lower invoice.