Every thermometer reaches your temperature using an algorithm. Therefore, it's normal for two digital thermometers to not exactly match. Some of the most basic models do something we call "bucketing" - which basically means that for a range of temperatures, it will always display the same thing. For example, all temps between 97.1 and 97.5 get reported as 97.3. In some ways, this makes these basic thermometers appear more consistent when they are actually less accurate. Wink is not designed to work this way, so making the switch to Wink can sometimes make your temps appear a little more erratic, when they are actually more accurate.
The algorithm in a thermometer basically looks at the upward pattern of your temperature and makes a predictive "guess" about your final temperature (otherwise, temping would take 10-15 minutes). We rigorously tested the algorithm in Wink to ensure it provided the quickest, most accurate reading; all your temperature readings should be within ±0.05°C (0.09°F) in the range of 33.0°C to 37.2°C (93.0°F to 99.0°F) and no individual reading will be more than ±0.10°C (0.18°F) outside typical body temperature range.
Wink is most accurate when placed as far into the heat pocket under your tongue as possible, so we suggest trying to perfect your placement and put your Wink in the same place every morning. With Wink, we've learned consistency is key. Place it under your tongue on the same side every day, as far back as is comfortable, and that leads to a more consistent reading.
Remember, the patterns that emerge while charting is more important than any 1 temperature. If your Wink is recording different temperatures from another BBT thermometer, that's pretty normal, and we encourage you to chart a cycle and compare the patterns!