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2016-2021 Honda Civic battery group size

The exact BCI group size your Civic takes — the code that decides which battery physically fits and reaches the cables. Cross-checked against the automaker's own chart and a retailer finder so you buy the right one the first time.

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Battery group size

51RFlooded lead-acid2 sources

Verified · cross-checked against 2 independent sources · Jun 2026

OE minimum CCA

≥ 500

Choose at least this — never a verified figure

A battery is bought by its group size. Shop Group 51R batteries that physically fit — double-check the group printed on the battery against your car before you buy.

Find a Group 51R battery on Amazon
Where this came from
  • HondaPartsNow genuine OEM battery part 31500-SR1-100M (group 51R baked in part title; fits 1992-2021 Civic incl. 10th gen) — source“31500-SR1-100M - Genuine Honda Battery (51R/500Amp85)”
  • carspecs.org Honda Civic battery-size table (BCI feed) — source“The 2018 Honda Civic Standard, Ex Type R has a group code of 51R , with a battery size of 9 3/8 x 5 1/16 x 8 13/16 inches (23.8 x 12.9 x 22.3 cm).”
  • Interstate Batteries 2023 Application Guide (BCI/Clarios feed — retailer finder, one witness) — source“Honda • Civic 2021-16 L4/1.5L 51R 410”

The group size carries our verified badge only when the automaker's own battery chart and an independent retailer finder agree on it — two genuinely separate sources, never two resellers of the same data. CCA is shown as an OE minimum, a “choose at least this” floor, never a verified number, because the right CCA is a property of the battery you pick. Your owner's manual is always the final word.