How to Build a Media Plan (a Practical Guide for Beginners)

When I hire junior marketers, one of the first things I ask for is a media plan. Building one tells me whether a person can think in numbers, make reasonable assumptions, and turn a vague goal into a concrete spending decision. It is the single most common test task I give, and a surprising number of people freeze on it.

Here is the good news: a media plan is not a fancy document. At its core it is a spreadsheet that answers one question, where does the money go and what do we expect back. In this guide I will walk you through what a media plan is, the inputs you need, how to split a budget across channels, and how to forecast and review results.

What a media plan actually is

A media plan is your bet, written down. You are saying, if I put this much money into these channels over this period, I expect roughly this many conversions at this cost. The value is not in being right to the penny. It is in making your thinking visible so you and your manager can sanity check it before any real money moves.Compare that to winging it, which usually means dumping a budget into whatever channel feels familiar and hoping it works. The problem is not that it always fails. It is that when it fails you have no idea why, and when it works you cannot repeat it. A plan gives you a baseline, so the moment actual results diverge from your forecast, you learn something real about your assumptions. It is the difference between a recipe and throwing things in a pan: both can make dinner, but only one lets you cook it again next week.

The inputs you need before you open a spreadsheet

Do not start by listing channels. Start by gathering the facts that constrain everything else. Most media plans go wrong because someone skipped this step and picked channels on vibes. Here is what I collect:

• Goal: what does success look like in plain terms. Installs, trials, demo bookings, purchases, signups. Pick one primary action so the whole plan points the same way.
• Budget: the total you can spend and the period it covers, for example 50,000 dollars over one quarter. Know whether it is fixed or can flex if results are strong.
• Target CPA or ROAS: the most you can pay per conversion, or the return you need on each dollar. If you do not have one, work it back from your margins or ask. This number is your guardrail.
• Audience: who you are trying to reach, where they are in the US, and what they already know about the product. This shapes which channels make sense.
• Timeline: when it runs, plus any seasonality, launches, or promotions that change demand. A plan for Q4 holiday traffic looks nothing like a quiet January.

If you are missing any of these, that is a question to ask, not a number to invent. In an interview, calling out a missing input scores better than guessing silently.

Splitting the budget across channels

Once you know the goal and audience, channel selection gets easier. The basic logic is to match intent to channel. Search ads catch people already looking for what you sell, so they convert well but have limited volume. Social and display ads reach people who are not searching yet, so they cost less per click but need stronger creative. Most US plans I build mix a high-intent channel with one or two demand-generation channels.For the actual split, weight spend toward channels you trust and put a smaller slice into ones you want to test. A common shape for a beginner plan is something like 60 percent into your proven workhorse channel, 25 percent into a secondary channel, and 15 percent reserved for testing. Those are not magic numbers, just a defensible starting position you can adjust as data comes in.Resist the urge to spread thin across six channels. With a modest budget, three channels run properly will teach you more than six channels starved of spend. Each channel needs enough budget to exit the learning phase and give you a readable result. If a channel cannot get at least a few dozen conversions in the period, it is probably too small to include yet.

Building and forecasting it in a spreadsheet

Now open a sheet. One row per channel (or per channel and audience, if you want more detail), and columns that walk from spend to expected outcome. Here is a structure that fits on one screen and answers every question a manager will ask:

• Channel: Google Search, Meta, YouTube, and so on
• Budget: dollars allocated to that row
• Est. CPM or CPC: your cost assumption
• Impressions / Clicks: budget divided by cost (expected volume)
• Est. CTR and CVR: your click-through and conversion rate assumptions
• Conversions: clicks multiplied by CVR
• Est. CPA: budget divided by conversions
• Notes: where each assumption came from

The forecast is just arithmetic. Say you put 10,000 dollars into a channel with a 2 dollar CPC. That is 5,000 clicks. At a 4 percent conversion rate you get 200 conversions, which is a 50 dollar CPA. Do that for each row, total it up, and compare the blended CPA to your target. If the plan says 70 dollars and your target is 50, you do not have a plan yet, you have a problem to solve before you spend.Be honest about where your assumptions come from. Past campaign data is best, public benchmarks are fine for a first draft, and a guess is acceptable only if you label it as one. The Notes column exists so future you remembers which numbers were solid and which were hopeful.

Leaving room to test, then reviewing actuals vs plan

A plan with zero testing budget assumes you already know everything, and you do not. Carve out a slice, that 15 percent from earlier works well, for new creatives, a new audience, or a channel you have never run. Treat it as tuition. Some of it will not pay back, and that is the point: you are buying information about what to scale next.The plan is not finished when you launch. It becomes useful when results come in and you put actuals right next to your forecast. Add columns for actual spend, actual conversions, and actual CPA, then look at the gaps. Did a channel beat its forecast? Find out why and consider shifting budget toward it. Did one miss badly? Check whether the assumption was wrong or the execution was. This review loop is what separates a planner from someone who just filled in a template.I review plans weekly for active campaigns and do a fuller readout at the end of the period. Over a few cycles your forecasts get sharper because you are feeding real numbers back into your assumptions, and that compounding accuracy is the whole reason the document exists.