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Marketers need to be more accountable than ever. If you have ever run a mix of television, radio, outdoor, print, online or social ads, you have probably been asked the question of what its impact was.

Each channel has a different measurement system, so to calculate the combined reach and frequency across all channels can be difficult. But don’t worry, here’s the formula to help!

Calculation for Combined Reach and Frequency Across Media Channels

Combined Reach = [(100 – (high reach))/100] x low reach + high reach

Combined Frequency = (GRP1 + GRP2)/combined reach


Now if you just read this and your head is spinning, here’s an example:

Example of Combined Reach and Frequency Across Media Channels

TV – 50% reach at a 4 frequency (200 GRPs)

Radio – 60% reach at a 5 frequency (300 GRPs)


Combined Reach = [(100 – 60)/100] x 50 + 60

= (40/100) x 50 + 60

= (.4 x 50) + 60

= 20 + 60

= 80

Combined Frequency = (200+300)/80

= 500/80

= 6.25

This campaign had a combined reach of 80% and an average frequency of 6.25.

Lastly, if you’re still confused at what a GRP is or how you’d go about calculating it for other media that doesn’t have reach and frequency per-se, here’s a helpful chart.

Chart Comparing Media Measurement by Channel

Media Measurement Type Example
Television Nielsen Ratings GRPs (gross rating points) 200 GRPs could mean 50% reach at a 4 frequency
Radio Nielsen Audio Ratings GRPs (gross rating points) 300 GRPs could mean 60% reach at a 5 frequency
Outdoor TAB Out of Home Ratings GRPs (gross rating points) & Weekly Impressions One billboard gets 700,000 weekly impressions, meaning 100,000 people per day pass it
Print Verified Audited Circulation Circulation and Readership A circulation of 100,000 with a readership of 400,000 means that 100k people receive it and an average of four people read each printed copy
Online 3rd Party Ad Server (usually DoubleClick) Impressions 1,000,000 impressions means an ad was displayed 1,000,000 times
Social Specific Channel (Facebook, Twitter) Reach/Frequency Facebook ads shows 75% reach at a 2.3 frequency to target audience


One caveat to all this is that although media buying is partly science it’s also partly understanding your audience and numbers. If you use the combined reach and frequency calculation and it’s giving you a really high number, please take in to account those of your target audience who may not consume media. Also remember that numbers are usually gathered using demographic information. For example, your TV ratings may be for adults 25-54 but your outdoor ratings may be for all vehicles.

Best of luck in measuring your ad effectiveness across different channels! If you need help please leave a comment or contact us and we will be happy to assist.

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  • Art 8 months ago Reply

    Super helpful thanks!

    I am pretty new to media, so have a quick question. Our OOH media plan does is not rated by showing. But I do have total Impressions (same for our digital). I am guessing there is no accurate way to combine these impression numbers using your formula… since we don’t have reach (against A25-54) or frequency. Let me know if I am wrong.

    By the way, the reason I am asking is because our leadership wants to compare our plan this year, to our plan last year using total impressions per 1,000 population (our geographies shifted). Not sure if that is the most accurate way of comparing so, I am hoping to compare R/F for a more holistic look.


    • Jason Alleger
      Jason Alleger 8 months ago Reply

      Hi Art,

      Great question. You are correct, comparing the reach and frequency between markets would be the best metric to keep everything comparable.

      You can actually calculate the R/F of outdoor if you have the total impressions and the daily effective circulation (DEC). Your outdoor company should be able to provide you with this – it’s how many people pass each board each day.

      Per board you’ll want to look at its DEC and calculate the reach in your market. You can look at census data to see what percentage of the population is ages 25-54. Let’s suppose your market has 1,000,000 people. If your DEC is 50,000 each day, you would take that and divide by your audience size, or 50,000/1,000,000 to get a 5% reach for that board. Then you’d want to look up census data to see how many adults 25-54 are in that market. If it’s 60% then you’d multiply your 5% market reach by 60% to get a 3% target audience reach. That’s per board.

      Then just plug that into the combined reach and frequency calculator per board and that should give you some usable numbers.

      • Tim 6 months ago Reply

        Hi Jason

        I’ve found this incredibly helpful thank you!

        I’m still missing a step though – trying to calculate r and f for outdoor media. Using your explanation above i can calculate reach per board. However to use the calculators I also need either frequency or GRP. Would you mind simplifying even more for me please, to find either of the above.

        Many Thanks

        • Jason Alleger
          Jason Alleger 6 months ago Reply

          Hey Tim – you’ll want to get the R/F for the combined boards. Any outdoor company you work with should provide this to you, as they are required to get audited numbers once per year.

  • Beth 7 months ago Reply

    I am currently building a marketing campaign proposal.

    I have collected a number of advertising quotes to build the campaign. There is a mixture of Radio, Print and direct mail that hit some of the same local areas. I don’t have access to frequency or GRPs but just the amount of listeners per station, circulation of the print and amount distributed to via direct mail.

    how do I calculate the combined total reach of this campaign using circulation, listeners and amount distributed to?

    Many Thanks

    • Jason Alleger
      Jason Alleger 7 months ago Reply

      Hi Beth,

      Good question. To solve this, you’ll just need a couple of things:
      1. Your total audience size – you can find this by looking up the census data. For Example, if your target audience was adults 18-54 in Utah, you could look up and see that the Salt Lake City DMA has 2.94 million people. Then you look at data for people who are ages 18-54 and see this is roughly 70% of the population, so now your audience is 2,058,000.

      2. Start with one medium, for example radio. Add up the total amount of unique listeners, and let’s say you find that it comprises 80% of your audience. So that means, if you bought 100% of air time you’d reach 80% of the target audience. That’s likely not the case, so you’ll have to use the data you have to determine a closer reach. If it’s a good schedule then maybe you’re hitting 60% of your audience. Take 60% reach and multiply it by your average frequency, and now you’ve got GRPs!

      Plug in GRPs by medium into the formula and you should be all set.

    • Michelle 6 months ago Reply

      Hi Jason,

      I found your responses to Tim to be very helpful. In your first reply to him, you stated that you can calculate reach and frequency if you have DEC and total impressions. In your second reply, you explained how to calculate reach from DEC and the target audience size (very helpful!).

      Can you explain how to calculate frequency from the impressions?


      • Jason Alleger
        Jason Alleger 6 months ago Reply

        Hi Michelle,

        You’d need a reach number and the impressions to figure out frequency. If they didn’t provide a reach number and it’s outdoor, you’d want to divide the impressions by 60 (2 impressions per day x 30 days). So if you had 60M impressions, divide that by 60 and you’d be reaching 1M unique people at an average of 60x per month. This is assuming a few things, especially that it’s a highly visible board. If the board(s) are less visible then drop the impressions per day or number of days accordingly.

  • Peter Bahemuka 7 months ago Reply

    I would like to get your help on answering one question. Our media campaign across media (radio and TV) reaches an aggregate audience of ~2 million people on a monthly basis. What would be the number of people reached by the 6-month campaign? Thank you.

    • Jason Alleger
      Jason Alleger 6 months ago Reply

      Hi Peter – it’d be 2 million people. You only count unique viewers.

  • Waseem 7 months ago Reply

    When we measure the frequency to be 6.25 as above example what does this means? what indicator does it gives to me? and is it a 6.25 out of 10?

    • Jason Alleger
      Jason Alleger 7 months ago Reply

      Frequency is the amount of exposures someone has to an ad. If you run a spot in the Super Bowl, you have a 1 frequency. If you run two spots in the Super Bowl, and Nielsen shows that the person was tuned in both times, then now you have a 2 frequency. So a 6.25 frequency means your target audience was exposed, on average, 6.25 times to your message.

  • Carlos Almeida 7 months ago Reply

    My name is Carlos, I am a student and I am currently taking my degree in Marketing at Coimbra Business School in Portugal.
    First of all thanks for the explanation and example.
    However I have some doubts, particularlly on how can I calculate the frequency. What kinda data do I need.

    Thanks for your help!

    • Jason Alleger
      Jason Alleger 6 months ago Reply

      Hi Carlos – you just need the audience size, how many impressions they were exposed to and the reach.

  • Ann Dupart 7 months ago Reply

    In your R/F example above, where you plug the actual reach numbers into the equation, you show division by 100 twice in that equation. Is that an error?
    It is not in the formula that you initially show.

    • Jason Alleger
      Jason Alleger 6 months ago Reply

      Good catch. This is now fixed. Thanks Ann!

  • Rabih 6 months ago Reply

    How we measure combined reach for more than 2 channels?

    • Jason Alleger
      Jason Alleger 6 months ago Reply

      You can just calculate it for the two channels for the largest reach, and then use that new reach and add in the third channel.

  • Tracey Afuwape 6 months ago Reply

    Hi Jason,

    Am having some difficulty achieveing an optimal frequency for a campaign am working on that will lead to conversion.
    What is an optimal frequency for a campaign?

    Thank you.

    • Jason Alleger
      Jason Alleger 6 months ago Reply

      It really depends on your brand, specifically its awareness and marketing mix, but for online campaigns it’s recommended running at a 10-15 frequency. Probably the way to calculate what your frequency should be would be to use Ostrow’s frequency model. It has you input a lot of variables (e.g. is this is new product or is it well-established already?) and gives you what frequency you should run at.

  • PIYOOSHA 6 months ago Reply

    Hi Jason
    Could you help me with this?

    I have to allocate advertising budget of $2million to media vehicles (TV, Newspaper, Magazine, Radio, Billboards, Online) in order to reach to a population segment of 25-70yrs in a specific city which has a total population of 30.8 million. I dont have the facts about the viewership, readership etc. So how do I go about it?


    • Jason Alleger
      Jason Alleger 6 months ago Reply

      You’ll want to get media buying software. In the U.S. agencies use Nielsen to measure TV and radio viewership. Print circulations are audited. Basically once you have the software and the data from measurement companies (like Nielsen) that will give you the information you need to make a sound marketing plan. If that seems daunting to you, we’d be happy to help.

  • Erica 6 months ago Reply

    Hi Jason,

    If we are using this tool against media types with different universe sizes (i.e., National TV and National Radio), what universe does the final calculation show reach against?


    • Jason Alleger
      Jason Alleger 6 months ago Reply

      Man, what a question! If it were me, I’d probably just use the latest census data for the target audience. National TV uses only the national TV audience universe, as does any other media type. I usually will look at MRI or Scarborough to figure out what the percent of my target audience is against the population size in the census data and work backwards from there.

  • Drew Bennett 6 months ago Reply

    Hi Jason,
    I’d be grateful if you could lend wise words to this problem.
    I have been asked to provide prospective reach information for a tv series that a sponsor is interested in funding. The sponsor’s product would be mentioned a minimum of 4 times throughout ad break lead in/outs of the show and the series comprises 12 shows. Further, the series is to be distributed to 10 broadcast territories i.e. UK, Scandinavia, Italy, India, SE Asia etc. In order to calculate reach what are the essential components of the equation to consider?
    Appreciate any advice, thanks.

    • Jason Alleger
      Jason Alleger 6 months ago Reply

      Hi Drew,

      If the product is mentioned 4x per show, then it seems like more of a frequency question than a reach question. Your reach will be your audience size in each broadcast territory. I’m sure those numbers are available from projections based on the time slot, channel, target audience and promotions that will run for the show.

      If it were me, I’d do it this way:
      UK reach – 2M viewers (market size 40M A18+)
      Scandinavia reach – 1M viewers (market size 18M A18+)

      These are just sample numbers, but you can easily calculate the reach and frequency per territory and then combine them all by using the formula in this article. The weekly frequency will be constant at 4x.

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