Ad Budget Calculator
Plan spend from the goal backwards. Tell the calculator how many customers or how much revenue you want, and it returns the ad budget required to get there.
Ad Budget Calculator
To acquire that many customers at this CAC, plan for $5,000 in spend.
Budget = Target new customers × Expected CAC.
Formula
By customers: Budget = Target customers × CAC · By revenue: Budget = Target revenue ÷ Target ROAS
Both methods solve the same question from a different known: if you know your CAC and a customer goal, multiply them; if you know a revenue goal and the ROAS you can realistically hit, divide. Use whichever input you have a confident estimate for.
Worked example
You want 100 new customers and your CAC is $50: budget = 100 × 50 = $5,000. Alternatively, to hit $50,000 in revenue at a 4× ROAS: budget = 50,000 ÷ 4 = $12,500.
What this tells you
Budgets set top-down (“we’ll spend $20k because that’s the number”) routinely miss targets. Setting them bottom-up — from a customer or revenue goal and a realistic efficiency assumption — ties spend to outcomes and exposes when a goal is simply unaffordable at your current CAC or ROAS. Run both methods and sanity-check that they roughly agree.
Benchmarks
Quick reference — budget needed at different goals and efficiency.
| Goal | Assumption | Budget |
|---|---|---|
| 100 customers | $50 CAC | $5,000 |
| 500 customers | $50 CAC | $25,000 |
| $50k revenue | 4× ROAS | $12,500 |
| $100k revenue | 3× ROAS | $33,333 |
Directional ranges only — your targets depend on margins, business model, and stage.
Common mistakes
Assuming CAC or ROAS holds as you scale — efficiency usually degrades with volume.
Setting the budget top-down from a round number instead of from a goal.
Leaving no buffer for the learning phase before campaigns stabilize.
Using an optimistic ROAS or CAC you have not actually hit on this channel.
When to use it
- Planning monthly or quarterly ad spend from a growth target
- Pressure-testing whether a goal is achievable at your current CAC/ROAS
- Splitting a revenue target into a defensible media budget
FAQ
Which method should I use?
Use the customer-goal method when you have a reliable CAC and a headcount or customer target. Use the revenue-goal method when leadership hands you a revenue number and you know the ROAS you can realistically sustain.
Should I add buffer to the budget?
Yes — these formulas assume your CAC or ROAS holds as you scale, but efficiency usually degrades with volume. Many teams add 10–20% headroom and revisit after the first weeks of data.
How do I estimate CAC or ROAS to plug in?
Use your trailing actuals from the same channel and season. If you're launching cold, start with a conservative assumption and let early data correct it.
Related calculators
Let Soku run the math — and the ads
Soku AI tracks ROAS, CAC, and MER live across Meta, Google, and TikTok, then optimizes spend toward your targets automatically.
Start free