// Free Tesla Battery Tool
Find out exactly how healthy your Tesla battery is — no VIN scan, no subscription needed. Enter your current full-charge range and EPA rating to get an instant battery health score, kWh remaining, year-by-year degradation projection to the 70% warranty threshold, charging habit impact, and — for used car shoppers — a clear Buy / Caution / Pass verdict.
Year-by-year projection based on your current health, mileage, and charging habits. The ⚠ row marks the 70% warranty threshold.
| Horizon | Odometer | Health % | Est. Range | kWh Retained | Buffer vs 70% |
|---|
How does your battery compare to the Tesla fleet average at the same mileage? Based on TeslaFi community aggregate data.
Evaluating a used Tesla? Enter the seller's claimed range and ask them to screenshot the Tesla app at 100% charge. Uses your model selection from Tab 1.
Common questions about Tesla battery health, degradation rates, warranty coverage, and how to read your battery capacity.
The best free method requires no third-party tools: (1) Charge your Tesla to exactly 100% — use Schedule Departure in the Tesla app to time it. (2) Open the Tesla app immediately after reaching 100% and navigate to the Charging section — look for "Rated Range." (3) Compare that number to your original EPA range. If your Model Y LR showed 330 miles when new and now shows 295 at 100%, your health score is 295 ÷ 330 = 89.4%. Enter those numbers in this calculator above for a full report including warranty status, kWh retained, and year-by-year projection.
Based on TeslaFi fleet data from 200,000+ vehicles: Tesla batteries typically lose 2–3% of capacity in the first year as cells condition, then slow to about 1% per year through years 2–5, and further slow to 0.5–0.8% per year after that. At 100,000 miles, the average Tesla retains roughly 90–92% of original capacity. At 150,000 miles: around 86–89%. This is significantly better than most competing EVs and far better than the early degradation fears from 2015–2018. Many Tesla Model S vehicles from 2015–2016 still retain 85%+ capacity above 200,000 miles.
Tesla warrants all current models to retain at least 70% of original battery capacity for the warranty period. Coverage by model: Model Y LR and Model 3 LR: 8 years or 120,000 miles. Model Y RWD and Model 3 RWD: 8 years or 100,000 miles. Model S and X: 8 years or 150,000 miles. If your battery falls below 70% within the warranty window, Tesla must repair or replace it at no cost. Importantly, this warranty is fully transferable to subsequent owners — meaning a used Tesla still within its original warranty window is protected for the new buyer too.
TeslaFi data shows vehicles that regularly charge to 100% degrade approximately 0.3–0.5% faster per year than those capped at 80%. Over 100,000 miles this accumulates to about 3–5% more total degradation. Tesla explicitly recommends setting your daily limit to 80% for routine driving. The exception: the night before a long road trip, charge to 100% — ideally timed to leave within 30 minutes of full charge. Since 2021, Tesla's battery management system has become significantly more protective at both charge extremes, reducing (but not eliminating) the impact of frequent high charges.
95%+: Excellent. Low mileage or exceptional care. 90–95%: Very Good. Typical for a well-maintained 3–4 year old Tesla. 85–90%: Good. Normal for 5–6 years/70,000–90,000 miles. Negotiate a small discount. 80–85%: Fair. Below average — verify warranty status, inspect carefully, negotiate harder ($1,500–$3,000 off). Below 80%: Concerning. Significantly degraded — check if still under warranty (could be a free Tesla repair), or negotiate an aggressive discount to account for eventual replacement cost (~$12,000–16,000 for Model 3/Y).
Cold reduces temporary range (recovers in warmer weather) but can cause permanent damage under specific conditions: charging a very cold battery at high DC fast-charging speeds, and repeated deep discharge below 10% in freezing temperatures. Tesla's thermal management system automatically limits these risks. For long-term battery health in cold climates: always precondition before charging (use Schedule Departure), keep the car plugged in overnight in extreme cold to maintain battery temperature, and avoid Level 3 DC fast charging when the battery temperature is below 32°F if possible. The Model Y and Model 3 heat pump (2021+) is significantly more efficient in cold than earlier resistive heating systems.
The range display fluctuates by 10–20 miles based on: recent driving efficiency, battery temperature, and the BMS's (battery management system) short-term learning algorithm. This is not real degradation. To get an accurate health reading, always check range at exactly 100% charge after the car has been stationary for at least 30 minutes. Avoid checking range after aggressive highway driving (will show lower) or after a short local trip in warm weather (may show higher than actual). The Tesla app's "Rated Range" at 100% is the most stable and reliable measurement.
Yes — Tesla has done this multiple times. Software updates can improve the BMS algorithm to more accurately estimate usable capacity, sometimes showing an apparent range increase of 5–15 miles without any physical change to the battery. This is not new capacity — it's more precise accounting of what was always there. Real physical capacity only ever decreases over time. However, BMS improvements can also improve actual efficiency by optimizing cell balancing and thermal management, providing small real-world range gains. The net result: Tesla's degradation curve often looks better than raw cell chemistry would suggest, partly due to ongoing software improvements.
TeslaFi ($10/mo): tracks your actual battery readings over time for a precise long-term degradation curve. Requires API access and months of data. Recurrent Auto ($20+ per report): uses your VIN and historical data to generate a paid battery health report. This calculator (free, no VIN): calculates your health score instantly from two numbers (observed range vs EPA), shows kWh retained, warranty status, year-by-year projection using fleet-average degradation curves, and provides a used-car buyer assessment. For a quick free assessment, this tool is comparable to Recurrent's paid report in practical terms. For ongoing long-term tracking, TeslaFi provides the most detailed data.
Increasingly significant as the used Tesla market matures and buyers become more educated. Battery health below 88% typically reduces resale value by $1,500–$4,000 compared to equivalent cars with 92%+ health, based on private-party sales data. Savvy buyers discount $300–$500 per percentage point below the fleet average for the same mileage. A Model Y at 83% health when fleet average is 91% (8 points below) could reasonably support a $3,000–$4,000 discount request. Always verify battery health before buying or selling — it's becoming as standard as a CarFax check.