Glucose Range in Diabetes: UK Targets Explained

Understanding the glucose range in diabetes is essential for managing the condition safely and effectively. Blood glucose targets in the UK are measured in millimoles per litre (mmol/L) and vary depending on whether a person has type 1 or type 2 diabetes, their age, and individual clinical circumstances. Keeping glucose within an agreed target range helps reduce the risk of both immediate symptoms such as hypoglycaemia and long-term complications including kidney disease, nerve damage and cardiovascular problems. This article explains what the recommended ranges are, what your readings mean, and when to seek advice from your GP or diabetes team.

What is a normal blood glucose range for people with diabetes?

The NHS recommends a target of 4.0 to 7.0 mmol/L before meals for both type 1 and type 2 diabetes, with post-meal targets of less than 9.0 mmol/L and 8.5 mmol/L respectively.

Target blood glucose ranges differ between type 1 and type 2 diabetes, and individual targets are always agreed with a diabetes care team. Blood glucose is measured in millimoles per litre (mmol/L) in the UK.

For adults with type 2 diabetes, the NHS recommends a target range of 4.0 to 7.0 mmol/L before meals and less than 8.5 mmol/L two hours after eating. For adults with type 1 diabetes, the NHS recommends a target of 4.0 to 7.0 mmol/L before meals and less than 9.0 mmol/L two hours after eating. These figures reflect a balance between avoiding hypoglycaemia (low blood sugar) and preventing the long-term complications associated with persistently elevated levels.

It is important to understand that these are general targets rather than rigid thresholds. A reading slightly outside the range on one occasion does not necessarily indicate a problem, but a consistent pattern of readings above or below target warrants a conversation with a GP or diabetes nurse. The goal of glucose management is to keep levels as stable as possible throughout the day, reducing the risk of both short-term symptoms and longer-term complications such as nerve damage, kidney disease and cardiovascular problems.

For people using continuous glucose monitoring (CGM) devices, an additional measure called Time in Range (TIR) is increasingly used. NICE guidance supports the use of CGM for people with type 1 diabetes. An international clinical consensus (ATTD, 2019, updated 2023) suggests a TIR target of more than 70% of readings falling between 3.9 and 10.0 mmol/L for most adults with diabetes; this is not a NICE-mandated figure and individual targets may be adjusted, for example for older adults or those with a history of severe hypoglycaemia.

How do target glucose levels differ by type of diabetes?

Type 1 targets are generally slightly higher post-meal than type 2, pregnancy requires stricter targets such as fasting glucose of 5.3 mmol/L or below, and older adults may have individualised, relaxed targets to reduce hypoglycaemia risk.

Target glucose ranges differ meaningfully between type 1 and type 2 diabetes, and are also adjusted for specific circumstances such as pregnancy, older age and the presence of complications.

For adults with type 1 diabetes, NICE (NG17) recommends a target HbA1c of 48 mmol/mol (6.5%) or below. NICE now recommends that all adults with type 1 diabetes are offered CGM.^[5][6] Where CGM is not used, self-monitoring of blood glucose is typically needed multiple times daily, including before meals, before bed and at other clinically relevant times, rather than twice daily alone.

For adults with type 2 diabetes, NICE (NG28) recommends an HbA1c target of 48 mmol/mol (6.5%) when managed with diet alone or with medications that do not carry a hypoglycaemia risk, rising to 53 mmol/mol (7.0%) for those on drugs that carry a hypoglycaemia risk, such as sulphonylureas or insulin.

Pregnancy introduces stricter targets. NICE guidance on diabetes in pregnancy (NG3) recommends fasting glucose of 5.3 mmol/L or below, one-hour post-meal glucose of 7.8 mmol/L or below, and two-hour post-meal glucose of 6.4 mmol/L or below for women with gestational diabetes or pre-existing diabetes. These tighter targets reflect the importance of glycaemic control for both maternal and foetal outcomes.

For older adults or those with frailty, hypoglycaemia avoidance often takes priority and targets are individualised; any relaxation of HbA1c targets should be agreed between the person and their clinical team based on their circumstances, comorbidities and risk of hypoglycaemia. Diabetes care is inherently personalised, and targets should always be agreed between the individual and their clinical team rather than applied uniformly. Online weight-management consultations, such as those offered by Bolt Pharmacy, a GPhC-registered UK online pharmacy, may involve prescriber review of metabolic health as part of a broader clinical assessment.

What do your blood sugar readings actually mean day to day?

A pre-meal reading of 4.0 to 7.0 mmol/L indicates good control; readings below 4.0 mmol/L signal hypoglycaemia requiring immediate treatment, and readings of 11.0 mmol/L or above indicate hyperglycaemia.

Day-to-day blood glucose readings provide a snapshot of how food, activity, medication and other factors are affecting your body at a given moment, and interpreting them in context is more useful than reacting to any single number. A reading of 4.0 to 7.0 mmol/L before a meal generally indicates good control, while a reading above 10.0 mmol/L two hours after eating may suggest that a meal contained more carbohydrate than the body could manage effectively at that time, though insulin timing or dose, physical activity and illness can all contribute.

Readings below 4.0 mmol/L indicate hypoglycaemia, which can cause symptoms including shakiness, sweating, confusion and, in severe cases, loss of consciousness. People on insulin or sulphonylureas are at greatest risk. The NHS advises treating a hypo promptly with 15 to 20 grams of fast-acting carbohydrate, such as glucose tablets or a small glass of fruit juice, followed by a longer-acting carbohydrate snack.

Blood glucose of 11.0 mmol/L or above is generally considered high (hyperglycaemia) by NHS guidance, and can cause thirst, frequent urination and fatigue.^[1] Persistent hyperglycaemia over weeks and months is reflected in a raised HbA1c, which measures average glucose over approximately 10 to 12 weeks.^[14][12] People with type 1 diabetes, and others at risk of diabetic ketoacidosis (DKA), should check blood or urine ketones when glucose is persistently elevated or when they are unwell, and follow their sick-day rules. Keeping a log of readings, including the time of day and any relevant context such as a large meal or missed medication, helps a diabetes team identify patterns and adjust treatment accordingly. Many people find structured self-monitoring, where readings are taken at consistent times, more informative than random checks.

Factors That Can Push Glucose Levels Outside the Target Range

Carbohydrate-rich meals, illness, missed medication and stress commonly raise glucose, while delayed meals, excess insulin and alcohol can cause it to fall below target.

Many everyday factors can cause blood glucose to rise or fall outside the target range, and understanding these helps people with diabetes make informed adjustments to their routine. The most common causes of elevated glucose include:

• Carbohydrate-rich meals, particularly those high in refined sugars or white starch

• Physical inactivity, which reduces insulin sensitivity

• Illness or infection, which triggers stress hormones that raise glucose

• Missed or reduced medication doses

• Certain medicines, including corticosteroids, some antipsychotics and thiazide diuretics

• Psychological stress, which can elevate cortisol and adrenaline

Conversely, glucose can fall below target due to:

• Delayed or missed meals

• Unplanned or prolonged physical activity

• Excess insulin or sulphonylurea dose

• Alcohol consumption, particularly on an empty stomach, which impairs the liver's ability to release stored glucose

When illness or infection is present, people with type 1 diabetes (and others at risk of DKA) should follow their sick-day rules, which typically include checking blood or urine ketones more frequently and not stopping insulin even if eating less. Seek urgent advice if ketone levels are elevated.

Hormonal changes across the menstrual cycle can also affect insulin sensitivity, with some women noticing higher readings in the days before menstruation. Similarly, the so-called dawn phenomenon, a natural rise in glucose in the early morning hours driven by hormonal activity, can push fasting readings above target even when evening control is good.

Understanding these influences allows people to anticipate fluctuations rather than be alarmed by them. Keeping a consistent routine around meals, activity and medication timing is one of the most effective ways to maintain stable glucose levels. Any new pattern of unexplained readings outside the target range should be discussed with a GP or diabetes nurse.

When should you contact your GP or diabetes team about your readings?

Contact your GP or diabetes team if fasting readings are repeatedly above 10.0 mmol/L, hypos are frequent or nocturnal, or if DKA symptoms are present; call 999 immediately for DKA or severe hypoglycaemia.

You should contact your GP or diabetes team if you notice a persistent pattern of readings outside your agreed target range, as this may indicate that your treatment plan needs reviewing. A single out-of-range reading is rarely cause for concern, but several consecutive high or low readings, or readings that are difficult to explain, warrant professional input.

Contact your GP or diabetes team promptly if you experience:

• Repeated fasting readings above 10.0 mmol/L over several days without an obvious cause

• Frequent hypoglycaemic episodes (readings below 4.0 mmol/L), particularly if they are occurring at night or without warning symptoms

• Symptoms of diabetic ketoacidosis (DKA), including nausea, vomiting, abdominal pain, fruity-smelling breath and rapid breathing, which are more common in type 1 diabetes

• Readings consistently above 15.0 mmol/L despite taking medication as prescribed

If you have type 1 diabetes or are otherwise at risk of DKA, check your blood or urine ketones when glucose is persistently high (for example, 13 mmol/L or above) or when you are unwell. If ketones are elevated alongside high glucose and DKA symptoms, call 999 immediately.

For symptoms of DKA or severe hypoglycaemia with loss of consciousness, call 999 immediately, as these are medical emergencies. For urgent advice that does not require an emergency response, NHS 111 is available around the clock.

Routine diabetes reviews, which NICE recommends at least annually for most people with type 2 diabetes and more frequently for those with type 1, are an important opportunity to review HbA1c, discuss glucose patterns and adjust targets or medication. Do not wait for a scheduled review if your readings are causing concern between appointments. Suspected adverse effects of diabetes medicines can be reported to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk.

How the NHS and NICE Recommend Monitoring Your Blood Glucose

NICE recommends CGM for all adults with type 1 diabetes and self-monitoring for type 2 patients on insulin or at hypoglycaemia risk; HbA1c is measured every three to twelve months depending on treatment stability.

NICE (NG17) recommends that all people with type 1 diabetes are offered continuous glucose monitoring (CGM), recognising it as more effective than finger-prick testing alone for achieving stable glucose control and reducing hypoglycaemia.^[5][6] For people with type 2 diabetes, NICE (NG28) recommends self-monitoring of blood glucose where it is likely to influence self-management, for example in those using insulin, those at risk of hypoglycaemia, or those who are pregnant.^[8][9] Access to CGM for adults with type 2 diabetes on insulin has also expanded under NHS commissioning; check with your GP or diabetes team for the most current local provision.

For people with type 2 diabetes managed with diet or non-insulin medication, routine self-monitoring is not universally recommended by NICE unless there is a specific clinical reason, as evidence for its benefit in this group is less clear. However, structured self-monitoring programmes, where readings are taken at agreed times and reviewed with a clinician, can support behaviour change and medication adjustment.

HbA1c testing remains a cornerstone of diabetes monitoring in the NHS. It is typically measured every three to six months when treatment is being adjusted, and every six to twelve months once stable.^[9][14] The NHS also offers structured education programmes such as DAFNE (Dose Adjustment For Normal Eating) for type 1 diabetes and DESMOND for type 2, which include practical guidance on interpreting glucose readings and adjusting management accordingly.

Local commissioning of CGM and monitoring supplies is determined by Integrated Care Boards (ICBs), meaning availability may vary across England. People in Scotland, Wales and Northern Ireland should check with their local health board. If you are unsure which monitoring approach is right for you, your GP or diabetes nurse is the best starting point for a personalised recommendation.

Scientific References

1. High blood sugar (hyperglycaemia).
2. Living with type 1 diabetes.
3. Low blood sugar (hypoglycaemia).
4. Gestational diabetes – Treatment.
5. Type 1 diabetes in adults: diagnosis and management (NG17).
6. Type 1 diabetes in adults: diagnosis and management (NG17) – Recommendations.
7. Continuous glucose monitoring | Type 1 diabetes in adults (QS208).
8. Type 2 diabetes in adults: management (NG28).
9. Blood glucose management | Type 2 diabetes in adults (NG28).
10. Diabetes in pregnancy: management from preconception to the postnatal period (NG3).
11. Diabetes in pregnancy (NG3) – Recommendations.
12. Type 1 diabetes | Treatment summaries – BNF.
13. Hypoglycaemia | Treatment summaries – BNF.
14. Diabetes | Treatment summaries – BNF.
15. Structured education programme | Type 2 diabetes in adults (QS209).

Frequently Asked Questions