Growth metrics are how a subscription business explains itself to investors, to a board, and to its own founders. They are also the metrics most often quoted wrongly: MRR that silently includes one-off setup fees, ARR that counts signed contracts nobody has paid yet, growth rates measured against a month that happened to be unusually weak.
Which one you want
MRR and ARR are the base: normalise every plan — monthly, annual, multi-year — into one comparable recurring figure, and use the ARR ↔ MRR converter when you need to move between the two. Runway is the one to run first if cash is finite; it tells you how many months of operation the bank balance actually buys at the current burn. Rule of 40 and Burn Multiple are the efficiency checks investors apply at Series A and beyond: growth rate plus profit margin should clear 40, and every dollar burned should buy a reasonable amount of new ARR.
What the numbers mean
Growth rate is meaningless without the base it grows from. Trebling from $10k to $30k MRR is a good quarter; trebling from $1M is a different company entirely, and the benchmarks investors apply scale accordingly — roughly 15%+ month-on-month is strong at seed, while 5–7% is strong at $10M ARR. Read any single month's figure alongside the trailing three: seasonality and a couple of large annual contracts distort a monthly number far more than most dashboards admit.