Blood sugar levels chart
What counts as normal depends on when you measured. The same 130 mg/dL is one thing fasting and another after lunch, so the chart below is split by context, and every specific reading from 40 to 400 mg/dL has its own page.
mg/dL or mmol/L both work; small numbers are read as mmol/L.
The scale at a glance
Below 54 mg/dL is a low that needs treating right away, and above 250 mg/dL deserves attention the same day. In between, context decides: the two tables below are the ranges labs and clinicians reference.
Normal ranges by context
| Range | Category |
|---|---|
| Below 70 mg/dL | Low |
| 70 to 99 mg/dL | Normal |
| 100 to 125 mg/dL | Prediabetes range |
| 126 mg/dL and above | Diabetes range |
| Range | Category |
|---|---|
| Below 140 mg/dL | Normal |
| 140 to 199 mg/dL | Prediabetes range |
| 200 mg/dL and above | Diabetes range |
Day to day, many people also track against a wider 70 to 180 mg/dL band; that is the band time in range is measured against. These are reference ranges for adults who are not pregnant, and a single meter reading is never a diagnosis.
Ranges for older adults
Targets loosen with age on purpose. For older adults, especially with other health conditions, the danger of a low outweighs the benefit of chasing tight numbers: a low can mean a fall, confusion, or a hospital visit within the hour, while the payoff of tight control arrives over many years. So clinicians set targets by overall health rather than age alone, following the American Diabetes Association’s framework.
| Overall health | A1C goal | Fasting / pre-meal | Bedtime |
|---|---|---|---|
| Generally healthyFew chronic illnesses; thinking and daily function intact | Under 7.0–7.5% | 80–130 mg/dL | 80–180 mg/dL |
| Complex or intermediateSeveral chronic illnesses, or some help needed day to day | Under 8.0% | 90–150 mg/dL | 100–180 mg/dL |
| Very complex or poor healthLong-term care or late-stage illness; comfort comes first | Not relied on | 100–180 mg/dL | 110–200 mg/dL |
These are starting points for a conversation, not rules: the right target for any one person is set with their clinician, weighing medications (insulin and sulfonylureas carry the low risk), hypoglycemia history, and what the person themselves values. If you track a parent’s or your own readings in SteadyRange, you can set the target band in Settings to match the plan you agreed on.
Most looked up
General information, not medical advice. Ranges follow the ADA diagnostic criteria. Convert units with the mmol/L to mg/dL converter or read how we calculate.
Stop looking numbers up one at a time
A page can tell you what a reading means in general. Your own log tells you what it means for you: log a reading in seconds and SteadyRange shows your time in range, estimated A1C, and the patterns behind them, on a private log you control.