The realme C100i is a tough little phone with a single big decision already made for you: it is 4G only. Around that choice it is honest work. IP64 plus MIL-STD-810H, a 6,500mAh battery, a 3.5mm jack, a memory card slot and a 120Hz screen, for Rs. 14,500 to Rs. 16,500 in its only configuration, 4GB + 64GB. This review is mostly about what that decision costs you, because at this money it is the whole question. Consider it if toughness is the brief. For most buyers, the same money buys 5G.
A naming note: realme sells this as the C100i. It is a 4G phone, and it is not the same device as a global "C100i" listed by some spec sites with a different chip and a 7,000mAh cell. The phone below is the one sold in India.
Built for the commute, not the showroom.
Start with the parts that will matter in year 2. IP64 is 2 separate promises: the 6 means dust-tight, the 4 means protected against splashing water from any direction. That is the rating that covers a monsoon walk to the bus stop and a dusty site visit, which is what most phones actually face. The MIL-STD-810H claim on top is realme's own testing against a military durability standard, and while it is not an independent drop rating, it tells you the phone was designed to be dropped. Some rivals at this price stop at IP52, which is a lighter promise against dripping water.
The 6,500mAh battery is large for a 210g phone, and on a 720p screen driven by a modest chip it has an easy job. The 3.5mm jack means the wired earphones in the drawer still work, and the microSD slot means 64GB is a starting point rather than a ceiling for photos and videos. The screen refreshes at up to 120Hz, so scrolling feels smooth, and reaches 900 nits in its high-brightness mode for outdoor use.
What "4G only" actually means for you.
This is the spec that decides the phone, so it deserves a plain explanation rather than a scare line.
What still works. Calls, WhatsApp, UPI payments, maps and video streaming all run on 4G, and India's 4G networks are not going anywhere soon. If the person using this phone mostly calls, messages and watches videos on Wi-Fi at home, 4G is genuinely enough today.
What you give up. A 5G phone on a 5G plan can use the faster network wherever it exists. A 4G phone never can, however long you keep it, and a phone bought at Rs. 15,000 is usually kept for 3 or 4 years. The cost of 4G only is not today, it is year 3.
Why it is 4G at all. The Unisoc T7250 chip inside is a 4G part. The same chip, and the same 166.5 x 78.2mm footprint, also turn up this season in OPPO's K14 Lite 4G and OnePlus's N6 Lite, which carry a 7,000mAh cell and a 13MP camera where the C100i has 6,500mAh and 8MP. The C100i is the lightest and least expensive way into that particular recipe.
The other numbers in that recipe. 15W charging into 6,500mAh is slow, and realme publishes no full-charge time, so we will not invent one; treat this as an overnight phone. HD+ on a screen this large means text is softer than on a Full HD panel. A single 8MP rear camera and 5MP front camera cover the basics, and no more. And realme has published no numbered update promise for this phone, only claims about long-term smoothness and battery health, which are not the same thing as committing to software updates.
Who should buy what, at about Rs. 14,000 to Rs. 18,000.
POCO C85x, about Rs. 15,500 for 4GB + 128GB, the configuration that can be ordered today: this is the comparison that decides it. For about the same money it brings 5G, twice the storage, a 32MP rear camera against 8MP, a bigger 6.9-inch 120Hz screen and a 6,300mAh battery at the same 15W, and it keeps the headphone jack. What it gives up is exactly the C100i's strength: it is rated only IP52, with no military-standard claim. Our POCO C85x review covers it.
OnePlus N6 Lite, about Rs. 17,000: the same Unisoc T7250 recipe, also 4G only, also IP64 with MIL-STD-810H, with a bigger 7,000mAh cell and a 13MP camera. It costs more for those 2 upgrades and changes nothing about the network question. See our OnePlus N6 Lite review.
OPPO K14 Lite 4G: the third phone built on this recipe, with 7,000mAh and 13MP. We could not confirm a listing that can actually be ordered today, so we print no price for it; our OPPO K14 Lite 4G review has the detail.
Tecno Spark 50 5G, about Rs. 18,000 for 4GB + 128GB: the stretch pick. About Rs. 2,000 to Rs. 3,500 more buys 5G, a 6nm Dimensity 6400 Ultimate, 45W charging into a 6,500mAh cell and a 50MP main camera, and it keeps IP64, a headphone jack and microSD. If the budget can reach it, it is the most complete phone in this group. Our Tecno Spark 50 5G review has the detail.
For the wider picture, our guides to the best phones under Rs. 15,000 and the best smartphones under Rs. 20,000 rank what is worth buying today.
- The phone has to survive dust, rain and drops before anything else
- You want a headphone jack and a memory card slot
- It is mostly for calls, WhatsApp and UPI, and 5G will not be missed
- You plan to keep it for 3 years or more and want the faster network
- You want charging faster than 15W
- Photos matter: 1 rear camera at 8MP is the floor, not a feature
Consider, for a narrow buyer. The realme C100i is the lightest and least expensive way into this season's tough 4G recipe: IP64 with MIL-STD-810H, 6,500mAh, a headphone jack and a card slot. For a parent, a field worker or a second phone that lives in a bag, that is a sensible brief and the C100i fills it honestly. For anyone else, the POCO C85x asks about the same money for 5G and twice the storage, and that is the better buy unless toughness is the whole point.
Tough, light and honest about what it is. 4G is a decision you make once and live with for years.
The price is for the only configuration, 4GB + 64GB, read from live listings at major Indian retailers on 8 October 2026; the launch price is labelled as such. Rival prices are live listings for each phone's base model, checked the same day. Specifications are confirmed against at least 2 independent sources each, led by the maker's own India specification; where sources disagreed, such as the exact screen size and the memory card limit, we left the figure out. Our verdicts are based on published specification, not on hands-on testing: we have not held this phone.
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