Prorated Tire Value Calculator
Calculate remaining usable tread value & betterment for warranty, insurance, and used tire sales.
QUICK EXAMPLE
You bought tires for $160 each with 10/32" original tread depth. You use 2/32" as the legal minimum (non-usable) tread depth. Today they have 6/32" remaining tread. That leaves 50% of the usable tread life (4/32" of 8/32"). The tire’s current prorated value is $80, and the remaining $80 is the betterment portion you’ve already used. An insurer or warranty that follows this formula would typically credit about $80 toward a comparable replacement tire.
New all-season tires often start around 10/32" (≈ 8 mm); winter and truck tires may be deeper.
Measure at the lowest point across the tread for safety and warranty decisions.
Many regions use 1.6 mm as the legal minimum; tread at or below this is treated as worn out.
Use your original purchase price or the current replacement price, depending on how your warranty or insurer calculates credit.
Usable Tread Remaining
45.3%
Based on usable tread above the minimum (1.6mm), matching many tread-based warranty and protection formulas.
Original
8mm
Current
4.5mm
Usable Remaining
2.9mm
Total Usable Tread
6.4mm
Tread depth is above both the legal minimum and typical “replace soon” thresholds. Continue normal use but monitor wear and age regularly.
Tread Depth Reference
Depth thresholds based on common safety and legal guidance for passenger tires.
| Depth (mm) | Approx 32nds | Status | Recommended Action |
|---|---|---|---|
| 8.0+ | 10+/32" | New / Excellent | Normal use |
| 6.0–8.0 | 7–10/32" | Good | Normal use; monitor wear |
| 4.0–6.0 | 5–7/32" | Fair | Monitor closely; plan ahead for replacement |
| 3.0–4.0 | 4–5/32" | Low (Replace Soon) | Wet traction declining; schedule replacement, especially before bad weather |
| 1.6–3.0 | 2–4/32" | Very Low | High risk in wet/snow; replace as soon as possible |
| ≤ 1.6 | ≤ 2/32" | Legal Minimum / Bald | Do not drive; immediate replacement required |
AI Insight
Powered by AIGet a plain-English explanation of your results — what they mean for your vehicle and driving experience.
Prorated Tire Value Examples (Original Price $160, Min Tread 2/32")
| Original Tread | Current Tread | % Usable Remaining | Prorated Value / Credit | Betterment (You Pay) |
|---|---|---|---|---|
| 10/32" | 8/32" | 75% | $120 | $40 |
| 10/32" | 6/32" | 50% | $80 | $80 |
| 10/32" | 4/32" | 25% | $40 | $120 |
| 10/32" | 2/32" | 0% | $0 | $160 |
These examples assume an original tread depth of 10/32", a minimum legal/policy tread depth of 2/32", and an original tire price of $160. Actual warranty credits may be based on current selling price and brand-specific terms.
How to Use This Calculator
- Enter the Original Purchase Price of one tire (or current replacement price, depending on what you want to compare).
- Enter the Original Tread Depth when new (most passenger tires start around 9/32" to 11/32", winter and truck tires may be deeper).
- Enter the Current / Remaining Tread Depth measured at the lowest point across the tread.
- Adjust the Minimum / Legal Tread Depth if needed (2/32" is common in many regions).
- Click 'Calculate Prorated Value'.
- Review remaining usable percentage, current value, and betterment (the portion you have already used).
Formula & Explanation
About Prorated Tire Value, Betterment & Tread Depth
What Is Tire Betterment (Proration)?
Tire betterment is how tire manufacturers, retailers, and insurance companies account for the tread you have already used. If a tire fails or is damaged before it is worn out, you usually receive a credit based on the unused portion of its life rather than a free replacement. The remaining cost you pay is the betterment amount that brings you back to your pre-loss condition instead of putting you ahead.
Tread-Based vs Mileage-Based Warranties
Some warranties are based on mileage (e.g., 60,000 miles), while others or additional adjustments are based on tread depth measurements. Mileage warranties compare the miles driven to the warranty mileage, while tread-based proration compares current depth to the original depth, adjusted for the minimum legal tread. This calculator focuses on the tread-based side, which is commonly used for both warranties and insurance betterment on tires.
Why 2/32" Is Treated as Worn Out
Many regulations and industry guidelines treat 2/32" of tread as the minimum legal and functional depth. Below this point, wet-weather grip and braking are significantly reduced, and tires are considered bald. That is why many warranty programs subtract 2/32" from both the original and current tread depths when calculating usable life and will not offer credit for tires that are already at or below 2/32".
Typical New Tread Depths by Tire Type
New all-season passenger tires usually start with about 10/32" to 11/32" of tread depth. Performance and summer tires often begin slightly shallower (around 8/32" to 10/32") to prioritize dry handling, while winter tires and light-truck/off-road tires can start around 11/32" to 12/32" or more to maintain grip in snow, mud, and rough conditions.
Safety Thresholds: 4/32" vs 2/32"
While 2/32" is often the legal minimum, many safety experts recommend planning tire replacement at around 4/32". At that point, wet traction and hydroplaning resistance start to decline noticeably. Using this calculator with both 4/32" (for safety planning) and 2/32" (for legal/warranty purposes) can give you a more realistic picture of both financial value and on-road safety.
How This Calculator Can Help You
- Warranty claims: Estimate what credit or charge to expect before you go to the shop.
- Insurance claims: Understand how betterment might reduce a payout for damaged tires.
- Used tire sales: Price used tires based on remaining usable tread instead of guesswork.
- Disputes and negotiations: Check whether a dealer’s proposed adjustment aligns with standard proration formulas.