Reach and Frequency Calculator: Formulas and Worked Examples
A reach and frequency calculator rests on one identity: impressions equal reach multiplied by average frequency. Impressions come from budget ÷ CPM × 1,000, reach is impressions ÷ frequency, reach % is reach ÷ audience, and GRPs are reach % × frequency. Combine two channels with A + B − (A × B), never by adding them.
This is the formula sheet. Every sum a planner needs for reach and frequency fits in one table, and the examples below run each one with Indian numbers. Once a campaign is live, our guide on how to check reach and frequency in DV360 shows where the delivered numbers appear and why they can drift from the plan.
What formulas does a reach and frequency calculator use?
Five terms do the work in every sum below: reach (unique people), average frequency (times each of them saw the ad), impressions (ads served), reach % (reach as a share of your target audience) and GRPs (reach % × average frequency).
Everything below comes from one identity: impressions = reach × average frequency.
| You know | You want | Formula |
|---|---|---|
| Budget and CPM | Impressions | Budget ÷ CPM × 1,000 |
| Impressions and frequency | Reach | Impressions ÷ Average frequency |
| Impressions and reach | Frequency | Impressions ÷ Reach |
| Reach and audience size | Reach % | Reach ÷ Audience × 100 |
| Reach % and frequency | GRPs | Reach % × Average frequency |
| GRPs and audience size | Impressions | GRPs ÷ 100 × Audience |
| Reach goal, frequency and CPM | Media budget | Reach × Frequency ÷ 1,000 × CPM |
| Reach % on two channels | Combined reach % | A + B − (A × B) |
All audience sizes and rates in the examples are illustrative.
Example 1: from budget to reach
A D2C skincare brand puts ₹8 lakh into YouTube bumper ads at a ₹160 CPM, aimed at women aged 18 to 34 in the top eight metros. Say the audience left after interest and in-market filters is about 50 lakh people.
- Impressions = ₹8,00,000 ÷ 160 × 1,000 = 50,00,000
- Reach at a planned average frequency of 5 = 50,00,000 ÷ 5 = 10,00,000 people
- Reach % = 10,00,000 ÷ 50,00,000 × 100 = 20%
- GRPs = 20 × 5 = 100
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Example 2: from a reach goal to a budget
An insurance brand wants to reach 40% of about 1.2 crore adults aged 25 to 44 in Mumbai, Pune, Nagpur and Nashik, at an average frequency of 3, across YouTube and OTT with a blended CPM of ₹220.
- Reach goal = 1,20,00,000 × 40% = 48,00,000 people
- Impressions = 48,00,000 × 3 = 1,44,00,000
- Media budget = 1,44,00,000 ÷ 1,000 × ₹220 = ₹31,68,000
- GRPs = 40 × 3 = 120
That ₹31.68 lakh is media only. Fees and GST come on top, and our programmatic advertising cost calculator shows how to add them.
Example 3: combining two channels
On an audience of 1 crore people, YouTube reaches 35% and OTT reaches 20%. Assuming the overlap is random:
- Combined reach % = 35 + 20 − (35 × 20 ÷ 100) = 48%, or about 48 lakh people, not 55 lakh
- If YouTube served 1.4 crore impressions and OTT 40 lakh, combined frequency = 1,80,00,000 ÷ 48,00,000 = 3.75
For three channels, combine the first two, then combine that result with the third. Real overlap is rarely random, so use this for planning and replace it with deduplicated reach from your reports once the campaign runs.
Example 4: the sanity check that catches impossible plans
₹40 lakh at a ₹200 CPM buys 2 crore impressions. At a planned frequency of 3, the formula says 66.7 lakh people. But if your target audience is only 50 lakh, that reach can't happen.
Even if you reached every single person, average frequency would be 2,00,00,000 ÷ 50,00,000 = 4. No campaign reaches everyone, so the real figure will be higher still. When a plan fails this check, widen the audience, add markets or reduce the budget.
Example 5: weekly frequency versus flight frequency
A four-week campaign reaches 10 lakh people a week at a frequency of 3. That's 30 lakh impressions a week, or 1.2 crore in total.
If the four weeks together reach 25 lakh different people:
- Flight frequency = 1,20,00,000 ÷ 25,00,000 = 4.8, not 12
- Flight reach is 25 lakh, not 40 lakh. Adding four weekly reach figures would overstate it by 15 lakh
Weekly reach always overlaps, so weekly figures can't be added up. Use deduplicated flight reach from your reports.
Example 6: effective reach at 3+
An average frequency hides how impressions were spread. Effective reach counts the people who saw the ad at least a set number of times, and many brand planners use three or more as the threshold.
In DV360, pivoted reach metrics give you the distribution. Suppose a report shows:
| Saw the ad | People |
|---|---|
| 1 or more times | 12,00,000 |
| 2 or more times | 7,20,000 |
| 3 or more times | 4,50,000 |
| 5 or more times | 1,80,000 |
Effective reach at 3+ is 4.5 lakh people, or 37.5% of everyone reached. The other 7.5 lakh saw the ad only once or twice. If the average frequency in this report were 4, you would never see that split without the distribution.
Example 7: reach from a cost-per-view line
YouTube skippable ads are usually bought per view, and views are not people. A view is counted when someone watches 30 seconds of the ad (or all of it, if it is shorter) or interacts with it, so many impressions never become views.
Say you put ₹4 lakh into skippable in-stream ads at ₹0.90 a view:
- Views = ₹4,00,000 ÷ 0.90 = about 4.44 lakh
- At a view rate of 28%, impressions = 4,44,444 ÷ 0.28 = about 15.9 lakh
- At an average frequency of 3, reach = 15.9 lakh ÷ 3 = about 5.3 lakh people
The view rate here is illustrative. Use your own history where you have it, and plan a low and a high case where you don't.
A reach and frequency calculator template
Copy this into a sheet, one column per scenario. The example column repeats Example 1.
| Row | What it is | Formula | Example | Your plan |
|---|---|---|---|---|
| A | Target audience | Input | 50,00,000 | |
| B | Media budget | Input | ₹8,00,000 | |
| C | CPM | Input | ₹160 | |
| D | Impressions | B ÷ C × 1,000 | 50,00,000 | |
| E | Planned average frequency | Input | 5 | |
| F | Estimated reach | D ÷ E | 10,00,000 | |
| G | Reach % | F ÷ A × 100 | 20% | |
| H | GRPs | G × E | 100 | |
| I | Sanity check | Is F well below A? | Yes |
For YouTube lines bought per view, convert the CPV into an effective CPM first, as our CPM calculator post explains, and use that in row C.
Which numbers should you plug in?
- Audience size. Use your own customer data, platform forecasts or a planning tool. Write it down as a range and run the template at both ends.
- CPM. Use indicative ranges by channel and buying type, adjusted for targeting and season. Our CPM benchmarks for planning a branding campaign show where in each range to start, and OTT rates and minimums are on our connected TV and OTT page.
- Frequency. As starting caps, our channel guides suggest three to five exposures a week for awareness video on OTT and for six-second bumpers, and two or three for longer non-skippable ads.
- Reach ceiling. One channel won't reach your whole audience. If row G creeps towards 100%, add a second channel instead of more budget.
These inputs usually come out of the media plan itself, which our guide on how to create a programmatic media plan covers step by step.
Where do reach and frequency sums usually go wrong?
- Adding reach across channels, weeks or line items. Always deduplicate.
- Using the all-in budget as media. Fees and GST don't buy impressions.
- Treating the average as everyone's number. Check the 1+, 3+ and 5+ distribution.
- Skipping the sanity check. If reach comes out bigger than the audience, the inputs are wrong.
Next step
Ask for a free media plan and a DV360 specialist runs these sums across channels for your industry, audience and budget, applies indicative rates, and sends estimated reach and impressions within one working day. When we run your campaigns, our DV360 Reports Section then shows the actual unique reach and frequency as the campaign delivers.
