Glossary
Growth, honestly compared.
Month-over-month sets this month against last month; year-over-year sets it against the same month a year ago. One reads momentum, the other survives the seasons.
growth = (this period − prior period) ÷ prior period × 100
MoM growth 5%
5% every month compounds to 80% for the year.
a $20,000 month becomes $35,917 in the same month next year.
Momentum and season
Month-over-month is the fast gauge. It tells you whether the line is still bending upward right now, and it will show a trend break weeks before any annual comparison does. Its weakness is that it cannot tell growth from calendar: almost every store sells more in November than in October, so a store that "grew 40% from October to November" mostly discovered Black Friday. Year-over-year removes the season — comparing November to last November holds the calendar still, so whatever difference remains is genuinely yours. If demand swings with gifting, weather, or BFCM, judge the business on YoY and keep MoM as the early-warning line.
Which one to trust
Trust the one that compares like with like. A month with five weekends against a month with four is not a fair fight, and neither is a promo month against a quiet one — if last March ran a sitewide sale and this March did not, YoY will read as decline when nothing broke. Before reacting to either number, check what sat behind it: the same number of selling days, the same promotions, and the same definition of revenue, because GMV and net revenue can grow at very different rates. Be suspicious of percentages on tiny bases, too. A jump from $2,000 to $4,000 is 100% growth and also one good wholesale order; at that scale, count dollars rather than percent. When the two measures disagree, believe YoY about the health of the business and MoM about what just changed — then go find out why it changed.
Made with care by Astral Commerce