Co-viewing means multiple people watching the same connected TV device at the same time. In India, co-viewing is the default — the household TV is a shared screen in most families, and prime time (8pm–11pm) is family viewing time. Industry estimates put the average co-viewing rate in India CTV at 2–3.5 people per session, rising to 3–5 during IPL and cricket matches.
For advertisers, this changes three things: (1) reach is higher than device impressions suggest — a campaign delivering 10 million device impressions may have reached 25 million people; (2) effective CPM per person is lower than the stated rate — a ₹400 CPM at 2.5x co-viewing is effectively ₹160 per person reached; (3) frequency caps set at the device level under-estimate how often household members are seeing the ad, leading to over-saturation if not corrected.
What to do about it
Apply a co-viewing multiplier (conservatively 2x, typically 2.5x in prime time) when calculating reach and cost-per-person. Use household IP-level frequency capping rather than device-level where platforms support it. Design creative for mixed-age household viewing, not individual consumption. And treat contextual targeting (content genre) as more reliable than demographic targeting on shared household devices.
Full guide
For a complete explanation, read: Co-viewing on CTV in India: what it means for reach, frequency, and measurement