How we estimate
Model 2026.10-v2 · last updated October 8, 2026
UsedPhoneValue.com provides mathematical estimates based on original retail pricing, phone age, depreciation assumptions, and user-reported condition. These estimates are not live resale quotes, verified transaction prices, or guaranteed selling prices. Actual resale values may vary significantly depending on market demand, location, carrier restrictions, device condition, and buyer preferences.
1. Why phones depreciate
New models launch every year, retailers discount older ones, batteries wear, and software support eventually ends. Most of the drop happens in the first year; after that, value falls more slowly.
2. The inputs
- Original US launch price (MSRP) for your exact storage size, checked against manufacturer announcements or reputable launch coverage. We never use promotional, carrier-discounted or trade-in prices, and never borrow another storage size's price. If we can't verify it, we ask you to enter it and widen the range.
- Official US release date.
- Today's date. Age is counted on the real calendar: whole months, plus the fraction of the current month elapsed. Leap years and month lengths are handled exactly, so estimates update every day.
- A depreciation profile for the phone's brand and type.
- The condition you describe.
3. The depreciation curve
We use a two-stage curve with no jumps at anniversaries:
- At purchase: an opened, used phone starts below MSRP (initial used discount).
- Year one: value glides smoothly (exponentially) from that starting point to the profile's 12-month retention.
- After year one: Value = MSRP × first-year retention × (1 − later annual decline)(age in years − 1).
- A working phone is never modeled below 5% of MSRP. Phones older than six years are flagged as very rough.
4. Depreciation profiles (model 2026.10-v2)
In October 2026 we checked the model against real used-phone prices for 29 phones (see section 5) and adjusted rates where the evidence was strong enough. Profiles marked "Calibrated" are backed by several comparable models; "Limited evidence" profiles rest on only a few, and "Assumption" profiles couldn't be calibrated. None of these rates is a scientifically established fact.
| Profile | Initial used discount | Kept after 12 months | Annual decline after | Range ± | Evidence |
|---|---|---|---|---|---|
| Apple iPhone | 12% | 82% | 21% | 15% | Calibrated |
| Apple iPhone Pro / Pro Max | 12% | 82% | 20% | 15% | Calibrated |
| Samsung Galaxy S | 15% | 58% | 20% | 20% | Calibrated |
| Samsung Galaxy Z foldables | 18% | 36% | 12% | 30% | Limited evidence |
| Samsung Galaxy A | 18% | 52% | 20% | 25% | Limited evidence |
| Google Pixel | 15% | 54% | 18% | 22% | Calibrated |
| Google Pixel Pro / XL / Fold | 15% | 54% | 22% | 25% | Limited evidence |
| Motorola Razr / Edge | 20% | 45% | 25% | 35% | Assumption |
| Motorola Moto G | 20% | 45% | 25% | 30% | Assumption |
- Apple iPhone: Calibrated in October 2026 against Swappa's public price guides (average unlocked asking prices, with private sales assumed to close about 10% below asking), checked to stay above buyback offers. Based on iPhone 13, 14, 15 and 16 (ages 2–5 years); the previous rates undervalued iPhones by roughly 15–30%. First-year retention is extrapolated, as the newest model's listings sit above launch price.
- Apple iPhone Pro / Pro Max: Calibrated in October 2026 against Swappa's public price guides (average unlocked asking prices, with private sales assumed to close about 10% below asking), checked to stay above buyback offers. Based on iPhone 14 Pro through 17 Pro (ages 1–4 years), which fit closely.
- Samsung Galaxy S: Calibrated in October 2026 against Swappa's public price guides (average unlocked asking prices, with private sales assumed to close about 10% below asking), checked to stay above buyback offers. Based on six Galaxy S and S Ultra models (S22–S25); previous rates undervalued them by roughly 20–25%.
- Samsung Galaxy Z foldables: Calibrated in October 2026 against Swappa's public price guides (average unlocked asking prices, with private sales assumed to close about 10% below asking), checked to stay above buyback offers. Foldables lose value very fast in year one and then level off. Based on Fold5, Fold6, Flip5 and Flip6 with few listings each, so the range is wide; previous rates overvalued them.
- Samsung Galaxy A: Calibrated in October 2026 against Swappa's public price guides (average unlocked asking prices, with private sales assumed to close about 10% below asking), checked to stay above buyback offers. Only two models with a handful of listings (A54, A35), so this is a partial adjustment with a wide range.
- Google Pixel: Calibrated in October 2026 against Swappa's public price guides (average unlocked asking prices, with private sales assumed to close about 10% below asking), checked to stay above buyback offers. Based on Pixel 7, 7a, 8 and 9; previous rates undervalued Pixels by roughly 20–30%.
- Google Pixel Pro / XL / Fold: Calibrated in October 2026 against Swappa's public price guides (average unlocked asking prices, with private sales assumed to close about 10% below asking), checked to stay above buyback offers. Based on only Pixel 8 Pro and 9 Pro; Pixel Fold has no usable evidence, so the range is wider.
- Motorola Razr / Edge: Not enough comparable listings to calibrate. The one data point found (Razr 2024, 2 listings) suggests this may undervalue Razr phones, so the range was widened rather than the rate changed.
- Motorola Moto G: Budget Motorola phones have very few resale listings. The one data point found (Moto G Stylus 2024, 2 listings) was within range, so the assumption is kept unchanged.
Why brands differ: iPhones have strong used demand and long software support, so they're assumed to hold value better. Android phones are discounted more aggressively at retail, which pulls used prices down faster. Foldables and budget phones have the least published evidence, so their ranges are widest.
Before and after calibration (v1 → v2)
| Profile | Kept after 12 months | Annual decline after | Range ± |
|---|---|---|---|
| Apple iPhone | 66% → 82% | 18% → 21% | 15% → 15% |
| Apple iPhone Pro / Pro Max | 68% → 82% | 17% → 20% | 15% → 15% |
| Samsung Galaxy S | 52% → 58% | 22% → 20% | 20% → 20% |
| Samsung Galaxy Z foldables | 48% → 36% | 25% → 12% | 25% → 30% |
| Samsung Galaxy A | 50% → 52% | 25% → 20% | 25% → 25% |
| Google Pixel | 50% → 54% | 23% → 18% | 22% → 22% |
| Google Pixel Pro / XL / Fold | 48% → 54% | 23% → 22% | 22% → 25% |
| Motorola Razr / Edge | 45% → 45% | 25% → 25% | 30% → 35% |
| Motorola Moto G | 45% → 45% | 25% → 25% | 30% → 30% |
5. How we checked it against real prices
We compared estimates with Swappa's public price guides for unlocked used phones, checked 2026-10-08. Swappa shows the average asking price of current listings (not completed sales) and a trade-in offer. Private sales usually close a bit below asking, so we aimed for estimates roughly 10% under the average asking price and above the trade-in offer. Phones with only a few listings carry less weight.
| Phone (good condition) | Launch price | Our estimate | Avg asking | Trade-in | Difference vs asking |
|---|---|---|---|---|---|
| iPhone 13 128GB | $799 | $253 | $286 (161) | $131 | -12% |
| iPhone 14 128GB | $799 | $318 | $340 (118) | $145 | -6% |
| iPhone 15 128GB | $799 | $405 | $440 (134) | $227 | -8% |
| iPhone 16 128GB | $799 | $512 | $609 (87) | $331 | -16% |
| iPhone 17 256GBNot used for fitting: Asking price is above launch price (supply-constrained new model) | $799 | $647 | $835 (11) | $434 | -23% |
| iPhone 14 Pro 128GB | $999 | $414 | $445 (65) | $234 | -7% |
| iPhone 15 Pro 128GB | $999 | $519 | $587 (90) | $293 | -12% |
| iPhone 16 Pro 128GB | $999 | $648 | $711 (85) | $399 | -9% |
| iPhone 17 Pro 256GB | $1,099 | $891 | $999 (69) | $591 | -11% |
| Galaxy S22 128GB | $799 | $207 | $230 (16) | $69 | -10% |
| Galaxy S23 128GB | $799 | $257 | $268 (17) | $103 | -4% |
| Galaxy S24 128GB | $799 | $318 | $380 (21) | $161 | -16% |
| Galaxy S25 128GB | $799 | $399 | $456 (7) | $233 | -12% |
| Galaxy S24 Ultra 256GB | $1,299 | $517 | $590 (31) | $299 | -12% |
| Galaxy S25 Ultra 256GB | $1,299 | $649 | $715 (26) | $392 | -9% |
| Galaxy Z Fold5 512GB | $1,919 | $524 | $635 (3) | $274 | -17% |
| Galaxy Z Fold6 512GB | $2,019 | $623 | $658 (11) | $385 | -5% |
| Galaxy Z Flip5 512GB | $1,119 | $306 | $294 (4) | $161 | 4% |
| Galaxy Z Flip6 256GB | $1,099 | $339 | $351 (5) | $197 | -3% |
| Galaxy A54 128GB | $449 | $133 | $155 (4) | $38 | -14% |
| Galaxy A35 128GB | $399 | $149 | $170 (3) | $45 | -12% |
| Pixel 7 128GB | $599 | $179 | $190 (5) | $54 | -6% |
| Pixel 7a 128GB | $499 | $167 | $198 (4) | $68 | -16% |
| Pixel 8 128GB | $699 | $254 | $279 (28) | $109 | -9% |
| Pixel 9 128GB | $799 | $345 | $379 (29) | $183 | -9% |
| Pixel 8 Pro 128GB | $999 | $329 | $357 (28) | $151 | -8% |
| Pixel 9 Pro 128GB | $999 | $411 | $455 (12) | $193 | -10% |
| Razr 2024 256GBNot used for fitting: Only 2 listings | $699 | $222 | $364 (2) | Not verified | -39% |
| Moto G Stylus 5G 2024 256GBNot used for fitting: Only 2 listings | $399 | $122 | $160 (2) | Not verified | -24% |
Estimates in this table are as of 2026-10-08; the calculator itself uses today's date. Number of listings in brackets.
6. Condition adjustments
These are provisional modeling assumptions, not verified market discounts. Swappa’s carrier breakdowns are consistent with the carrier-lock deduction (a T-Mobile iPhone 14 lists about 17% below unlocked, AT&T about 7%), but the other deductions aren’t independently verified. Pick one appearance grade (they're mutually exclusive, so a cracked screen is never also charged for scratches):
- Excellent, near-new appearance: +5%
- Good, normal wear: baseline
- Light screen scratches: −10%
- Heavy scratches or noticeable dents: −20%
- Cracked screen: −35%
Independent issues are applied separately:
- Cracked back glass: −20%
- Battery health below 80%: −10%
- Carrier-locked: −10%
Adjustments are multiplied, never added. Example: $450 × 0.90 = $405, then another −10% gives $405 × 0.90 = $364.50. We never subtract a percentage of the original MSRP.
For serious faults — won't power on, activation / account locked, display doesn't work, logic board or major internal failure — we don't produce a number, because ordinary deductions can't capture them. An activation-locked phone can't be resold normally.
7. The range
The range is the estimate ± the profile's uncertainty, widened by 5 points for phones over three years old, 5 points for cracked screens or back glass, and 10 points when you enter the original price yourself (capped at ±50%), then rounded to the nearest $5. It reflects how unsure our assumptions are — it is not a statistical confidence interval or a verified market range, and we never show a confidence badge for it.
8. Projections and the resale sweet spot
The same curve gives modeled values 3, 6, 12 and 24 months ahead. The chart's line before today is the model's theoretical path, not measured prices. Future projections are uncertain: launches, promotions and demand can move real prices either way.
An estimated sweet spot is not a guaranteed best time to upgrade. A phone can keep losing resale value and still be the cheapest thing to keep using. We show the trade-offs and let you decide.
9. Verified market reference (separate)
We still keep a database of real, approved, dated price records. When there are enough comparable records for your exact phone, we show them separately as a verified market reference — never blended into the estimate. Records of different types are never mixed:
- Completed sales: what a buyer actually paid.
- Asking prices: what sellers list for, often higher than what sells.
- Buyback offers: instant quotes from buyback companies, usually lowest.
- Manufacturer trade-in offers and promotional credits: often tied to buying a new phone.
Market ranges use only records from the last 90 days for the same model, storage and condition: at least 3 records on 2+ days, outliers removed beyond 3 scaled MADs, shown as the 25th–75th percentile.
10. Sell or keep
The Sell or Keep calculator compares keeping (repairs plus further modeled loss in value) with upgrading (replacement price, minus what you get for your phone, minus the new phone's remaining value) over the same number of months. You can drop in our depreciation estimate or your own real offer, and edit every assumption.