🧮 Tools for used iPhone buyers
Enter a few numbers – get results instantly, with suggestions of products highly scored by the community. No sign-in, and your data is not stored.
🔋 Should your iPhone battery be replaced?
Open Settings › Battery › Battery Health & Charging to see “Maximum Capacity”.
✅ 12-step used iPhone checklist
Tick the items the phone passes, then score it. Take this checklist with you when viewing a phone.
❤️ Read a blood pressure result
Enter the reading you just took (rest seated for at least 5 minutes first). Classified according to Vietnam National Heart Association recommendations.
| Category | Systolic | Diastolic |
|---|---|---|
| Optimal | < 120 | and < 80 |
| Normal | 120 – 129 | and/or 80 – 84 |
| High normal | 130 – 139 | and/or 85 – 89 |
| Grade 1 hypertension | 140 – 159 | and/or 90 – 99 |
| Grade 2 hypertension | 160 – 179 | and/or 100 – 109 |
| Grade 3 hypertension | ≥ 180 | and/or ≥ 110 |
| Low blood pressure | < 90 | or < 60 |
⚖️ BMI & healthy weight calculator
Based on thresholds for Asian adults (WHO Western Pacific Region), for people aged 18 and over.
💧 How much water should you drink each day?
Estimated at 30–35 ml per kg of body weight, plus extra when you sweat during exercise.
🔥 Daily calorie needs (TDEE)
Mifflin–St Jeor formula – for reference when planning meals to maintain, lose or gain weight.
💡 Results are for reference only. Inspect the phone in person and ask about warranty and returns before buying.