What this tool answers
You need a first-pass portable jump-starter size before buying. Enter engine displacement in liters and fuel type (1 gasoline / 2 diesel). The calculator names the smallest class on this site’s ladder — 1000A, 1500A, or 4000A peak — that clears the published liter ceiling for that fuel, or returns NO_MATCH. It is not a battery diagnosis, CCA lab test, or substitute for manufacturer instructions.
Why liters and fuel matter
Retail jump-starter listings often rate peak amps against gasoline and diesel displacement ceilings because diesel engines typically need more cranking effort at the same liter size. Matching both inputs avoids undersizing against the diesel column or oversizing without checking gas limits.
Class ladder on this site
Classes use published VEVOR US jump-starter ratings checked 2026-09-10: (1) 1000A peak for ≤5L gas / ≤3L diesel, (2) 1500A for ≤6L gas / ≤4L diesel, (3) 4000A for ≤10L gas / ≤8L diesel. Matching rule: smallest class where liters ≤ that class’s limit for the selected fuel.
When the answer is NO_MATCH
If liters exceed 10L on gasoline or 8L on diesel (or both), this site returns NO_MATCH for its published ladder. Typical next steps: confirm displacement units, check for a larger commercial booster outside this screen, or follow vehicle manufacturer guidance. Do not force an undersized pack.
12V polarity, charge, and battery condition
Use on 12V systems only. Connect red clamp to positive (+) and black to negative (−) or a manufacturer-approved ground. Keep the pack charged. Do not use on frozen or damaged batteries without manufacturer guidance — risk of rupture or fire. Wear PPE. Repeated no-starts usually mean the battery or charging system needs service; a jump pack is not a permanent fix.
Sources
VEVOR US jump-starter product pages for peak-amp and gas/diesel liter claims dated in products.json (checked 2026-09-10). Consumer sizing practice pairing displacement with fuel type. Safety framing follows common manufacturer warnings: 12V only, correct polarity, charged pack, frozen/damaged battery caution, and PPE.