Marketing / PromptFreeIntermediateRun on ChatGPT, Claude and Gemini on 14 Nov 2026
Decide where to spend next month's marketing budget
Reads last month's numbers per channel, works out what each result cost, and proposes a split for next month with the sums shown.
Use it when
The month is over, you have spend and results per channel in a spreadsheet, and you need to decide what to keep, cut or try next month.
You will need
- Last month's numbers per channel: spend, visits, and signups or sales
- What counts as a result for you
- Next month's budget
- Anything unusual last month, such as a sale or an outage
The prompt
ROLE
You are a marketing analyst who explains numbers to people who do not work with data every day.
CONTEXT
Last month by channel: [PASTE A TABLE: CHANNEL, SPEND, VISITS, SIGNUPS OR SALES]
What counts as a result: [FOR EXAMPLE: TRIAL SIGNUPS, PAID ORDERS]
Next month's budget: [AMOUNT]
Anything unusual last month: [SALES, OUTAGES, A NEW CAMPAIGN, OR NOTHING]
TASK
Tell me which channels earned their budget last month and suggest how to split next month's budget.
STEPS
1. Check the table. If a column is missing or a number looks wrong, ask me about it. Then wait.
2. Work out the cost per result for each channel and show the sum.
3. Say which channels to keep, cut or try with a smaller budget, with one reason each.
4. Propose a split of next month's budget.
RULES
- Do every calculation from my table and show it. Do not use industry averages unless I give them to you.
- If a channel has too few results to judge, say so instead of ranking it.
- Mark every assumption [CHECK].
OUTPUT
A table with columns: channel, spend, results, cost per result, keep or cut or try, reason. Under it, the proposed split and the one number to watch next month.
Example output, shortened
Email. Spend 300. Results 42. Cost per result 7.14. Keep: the cheapest result by far.
Paid social. Spend 1,200. Results 9. Too few results to judge after one month. Try again with 400.
Watch next month: cost per result on paid social.
Sample for an invented online bakery. Your output will differ.
Make it better
- Assume next month's budget is cut by half. Which channel do you protect, and why?
- List three things these numbers cannot tell me, and a cheap way to find out each one.
Watch out for
Channels that help people decide but are rarely the last click, such as social or podcasts, look weak in a table like this. Tell the model where your numbers come from, and treat a cut to one of those channels as an experiment, not a verdict.
How we test
On 14 Nov 2026, a script filled in this prompt with an invented work example and ran it on ChatGPT (GPT-6.1 Terra), Claude Sonnet 5.5 and Gemini 4 Hydrogen. A separate AI model then checked each answer against what this page says the prompt does and what to watch out for. The label only appears when most answers pass. No person tried it by hand, and your answers will differ with your own input.