· 4 min read · ROAS Chart
How much to increase your ad budget, and when to stop
The usual advice for scaling Meta ads is to raise the budget by about 20% at a time. That advice is about not disturbing the algorithm. It says nothing about whether the extra spend makes money. This is the part it leaves out.
Why 20% at a time
Large, sudden budget changes can push a campaign back into its learning phase, and delivery gets erratic while it re-learns. Raising budgets in steps of around 20%, a few days apart, keeps delivery stable. It is a sensible rule for the platform. It is not a profit rule, because it does not tell you what ROAS you need at the new budget.
Every budget has its own break-even
A fitness gear store: $80 average order, 65% gross margin, $8 shipping, 3% payment fees, 5% of orders refunded. Each order leaves $39.00, a 48.8% contribution margin. Fixed costs are $8,000 a month.
Today it spends $15,000 a month at 3.40x. Break-even at that budget is 3.15x, so the month makes $1,863.
As the budget rises, two things fall. ROAS usually falls, and so does break-even, because the same fixed costs are spread over more revenue. The question at each step is which one falls faster.
How much ROAS you can afford to lose
The useful number at each step is the ROAS that would earn exactly what you earn today. Land above it and the step made you money. Land below it and you are spending more to make less.
| Monthly budget | Break-even ROAS | Same profit as today |
|---|---|---|
| $15,000 (today) | 3.15x | 3.40x |
| $18,000 | 2.96x | 3.18x |
| $21,600 | 2.81x | 2.99x |
| $25,920 | 2.68x | 2.83x |
| $31,104 | 2.58x | 2.70x |
Each 20% step can absorb roughly 0.15 to 0.2 of ROAS before profit falls below today's. On the chart, that is the same-profit line running through your current point: follow it to the right and it gives the lowest ROAS that keeps you level at every budget.
A worked scaling run
Say the store steps up and ROAS slides, as it usually does:
- $18,000 at 3.20x: profit $2,080. Above the 3.18x line, so the step paid. Keep going.
- $21,600 at 3.00x: profit $1,990. Just above the 2.99x line. Still level, but the safety margin is gone. Hold here and let the campaign settle.
- $25,920 at 2.90x: profit $2,724. ROAS fell again, but by less than the 2.83x line allows, so this is the most profitable month of the run.
The rule that falls out of it: step up while ROAS stays above the same-profit line, hold when it lands on the line, and step back if it falls below.
When to stop
Stop when ROAS settles on the same-profit line and stays there once the campaign has stabilised. Spending beyond that point buys revenue, not profit.
If you are below break-even today, scaling can still help, because break-even falls as spend rises. That only works while your ROAS is above your floor, 2.05x for this store. Below the floor every extra dollar loses money, whatever the budget. For the lowest budget that can work at all, see how much to spend on Facebook ads, and for what scaling does to ROAS, why ROAS drops when you scale.
Every figure in this article comes from the ROAS Chart calculator, and the screenshots show it with the same numbers. The formulas are written out on the math behind it.