Gestational Diabetes Blood Sugar Checker
You have a number on a meter and nobody to ask until your next appointment. Enter it below with the time you took it and you get a straight answer in about fifteen seconds — plus the target it is being measured against, and what to do about it.
Under ADA / ACOG, a gestational diabetes reading is on target when it is below 95 mg/dL (5.3 mmol/L) fasting, and below 140 mg/dL one hour after a meal. Anything under 70 mg/dL is too low and needs treating rather than celebrating. Those cut-offs are not universal — the United Kingdom, Australia, Denmark and the United States all publish slightly different ones, which is why the checker asks where you are and the full comparison sits further down this page.
Gestational diabetes blood sugar targets by country
The targets you should be measuring against depend on who is looking after your pregnancy. These are the published self-monitoring targets from the seven guidelines most commonly used in English, Spanish, French and Danish-speaking care.
| Guideline | Fasting | 1½ h after | 1 h after | 2 h after |
|---|---|---|---|---|
| United StatesADA / ACOG | < 95 mg/dL5.3 mmol/L | — | < 140 mg/dL7.8 mmol/L | < 120 mg/dL6.7 mmol/L |
| United KingdomNICE (NG3) | < 5.3 mmol/L95 mg/dL | — | < 7.8 mmol/L141 mg/dL | < 6.4 mmol/L115 mg/dL |
| CanadaDiabetes Canada | < 5.3 mmol/L95 mg/dL | — | < 7.8 mmol/L141 mg/dL | < 6.7 mmol/L121 mg/dL |
| Australia & New ZealandADIPS | ≤ 5.0 mmol/L90 mg/dL | — | ≤ 7.4 mmol/L133 mg/dL | ≤ 6.7 mmol/L121 mg/dL |
| SpainGEDE | < 95 mg/dL5.3 mmol/L | — | < 140 mg/dL7.8 mmol/L | < 120 mg/dL6.7 mmol/L |
| FranceCNGOF | < 0.95 g/L5.3 mmol/L | — | < 1.40 g/L7.8 mmol/L | < 1.20 g/L6.7 mmol/L |
| DenmarkDSOG | ≤ 5.3 mmol/L95 mg/dL | ≤ 7.0 mmol/L126 mg/dL | — | — |
The smaller figure under each target is the same number in the other unit. A dash means that guideline publishes no target for that testing time. Individual clinics sometimes set slightly tighter targets than their national guideline — if yours has given you numbers, use those.
What counts as slightly over versus genuinely high
A target tells you where the line is, not how far past it you are. These are the bands the checker uses, shown here for ADA / ACOG in mg/dL.
| When tested | In range | Just over | Over target | Call today |
|---|---|---|---|---|
| Fasting | < 95 | 95–105 | 105–126 | ≥ 126 |
| 1 hour after a meal | < 140 | 140–154 | 154–200 | ≥ 200 |
| 2 hours after a meal | < 120 | 120–132 | 132–200 | ≥ 200 |
LowReadings that are too low
Below 70 mg/dL is hypoglycemia and needs treating before anything else: 15 g of fast-acting carbohydrate, wait 15 minutes, test again. Below 54 mg/dL, treat it immediately and call your maternity team once you have. Lows are uncommon on diet alone but a real risk once you are on insulin, and they are the one situation where the answer is to eat sugar rather than avoid it.
Anything at or above 200 mg/dL at any time of day — or 126 mg/dL fasting — is treated as a same-day call rather than a diet adjustment. Just over means the target plus ten per cent, which is roughly the range where a single meal explains the number.
mg/dL, mmol/L and g/L — the same reading in three units
The United States and Spain report blood glucose in mg/dL, the UK, Canada, Australia and Denmark in mmol/L, and France in g/L. It is one measurement written three ways, which is why an answer from another country can look alarming until you convert it. Here is every number that matters in gestational diabetes care, in all three.
| mg/dL | mmol/L | g/L |
|---|---|---|
| 54 | 3.0 | 0.54 |
| 70 | 3.9 | 0.70 |
| 90 | 5.0 | 0.90 |
| 92 | 5.1 | 0.92 |
| 95 | 5.3 | 0.95 |
| 101 | 5.6 | 1.01 |
| 115 | 6.4 | 1.15 |
| 120 | 6.7 | 1.20 |
| 121 | 6.7 | 1.21 |
| 126 | 7.0 | 1.26 |
| 133 | 7.4 | 1.33 |
| 140 | 7.8 | 1.40 |
| 141 | 7.8 | 1.41 |
| 153 | 8.5 | 1.53 |
| 155 | 8.6 | 1.55 |
| 180 | 10.0 | 1.80 |
| 200 | 11.1 | 2.00 |
To convert by hand: divide mg/dL by 18 for mmol/L, or multiply mmol/L by 18 for mg/dL. g/L is simply mg/dL divided by 100.
Convert any other number, in both directionsDiagnostic thresholds are not daily targets
This is the single most common way a glucose number gets misread in pregnancy. The thresholds below come from the glucose tolerance test that diagnoses gestational diabetes, and they are far higher than the daily targets above. If you are holding an OGTT result, read it against this table — not against your fasting target, which will make a perfectly ordinary test result look catastrophic.
| Criteria | Fasting | 1 h | 2 h | 3 h | Diagnosis when |
|---|---|---|---|---|---|
| IADPSG / WHO75 g glucose drink | 92 mg/dL5.1 mmol/L | 180 mg/dL10.0 mmol/L | 153 mg/dL8.5 mmol/L | — | 1 value at or above threshold |
| NICE (NG3)75 g glucose drink | 101 mg/dL5.6 mmol/L | — | 141 mg/dL7.8 mmol/L | — | 1 value at or above threshold |
| Carpenter–Coustan100 g glucose drink | 95 mg/dL5.3 mmol/L | 180 mg/dL10.0 mmol/L | 155 mg/dL8.6 mmol/L | 140 mg/dL7.8 mmol/L | 2 values at or above threshold |
Which criteria your service uses depends on where you are. Every value is the threshold at or above which that result counts as abnormal.
How the verdict is worked out
Nothing here is a black box. This is the whole method, in the order the checker applies it.
- 1
Your reading is converted to one unit
Whatever you type — mg/dL, mmol/L or g/L — is converted to a single internal unit before anything is compared, so the verdict can never depend on which unit you happened to pick. Readings outside 20–600 mg/dL are rejected rather than classified, because that is the range a home meter can actually report.
- 2
The low end is checked first
Anything below 70 mg/dL / 3.9 mmol/L is called low, and below 54 / 3.0 very low, regardless of when it was taken or whose targets you chose. A checker that only ever compares upwards would tell someone with a reading of 3.1 that they were in range, and that is the one mistake a tool like this must not make.
- 3
Your guideline's target for that timing is looked up
Each guideline publishes a target per testing time, and some write them as below X while others write X or below. The checker honours that distinction, which is why a reading of exactly 5.0 fasting is in range under ADIPS and marginal under a strictly-below guideline.
- 4
The gap decides the band
In range is under target. Just over is from the target up to ten per cent above it, which is roughly the range where one meal explains the number. Anything above that is over target.
- 5
Two levels escalate regardless
200 mg/dL / 11.1 mmol/L at any time of day, or 126 / 7.0 fasting, is reported as a same-day call rather than a diet adjustment, whichever guideline you chose. These are levels where waiting for the next appointment is not the right advice.
- 6
The same reading is run against every other guideline
Finally the reading is compared to all seven sets of targets, so you can see whether the verdict would change in another country — and whether the conflicting numbers you found online actually conflict, or were simply published somewhere else.
Frequently asked questions
What counts as a normal blood sugar reading in gestational diabetes?
Under the most widely used targets, from the ADA and ACOG, a reading is on target below 95 mg/dL / 5.3 mmol/L fasting, below 140 / 7.8 one hour after a meal, and below 120 / 6.7 two hours after a meal. The UK sets the two-hour target lower at 6.4 mmol/L and Australia sets fasting lower at 5.0 mmol/L. Below 70 mg/dL / 3.9 mmol/L is too low at any time of day and needs treating.
My reading is a few points over target. Should I panic?
No. One reading slightly over target means very little — sleep, stress, illness, how early you tested and the exact make-up of a single meal all move one number. What your team acts on is the pattern: the same slot over target two or three times in a week is the signal. A reading far over target, or anything at or above 200 mg/dL / 11.1 mmol/L, is a different situation and worth a call today.
Why do UK and US gestational diabetes targets differ?
Because the guideline committees weighed the same evidence differently. NICE sets the two-hour target at 6.4 mmol/L where the ADA uses 6.7, and ADIPS in Australia sets fasting at 5.0 where most others use 5.3. The differences are small in absolute terms but big enough that the same reading can be fine in one country and just over in another. Use the targets your own team gave you — this tool shows the others so you can see why the internet disagrees with itself.
I tested at 45 minutes instead of an hour. Does that matter?
Yes, quite a lot. Most meals peak somewhere between 45 and 75 minutes, so testing early tends to catch the peak and read higher than the target was designed for. Start the clock at your first bite rather than when you finish eating, and test at a true 60 or 120 minutes. If a reading looks unexpectedly high, the timing is the first thing to rule out.
What should I do about one high reading?
Write down what you ate and drank in the two hours before it, then carry on with your normal testing. Do not skip the next meal or cut carbohydrate sharply — under-eating in pregnancy causes ketones and hides the real pattern from your team. If the same slot is over target more than about twice in a week, that is the point to contact your midwife or dietitian.
Can my blood sugar be too low with gestational diabetes?
Yes. Below 70 mg/dL / 3.9 mmol/L is low for anyone. On diet alone it is uncommon and usually follows a long gap between meals; on insulin or certain medications it is a genuine risk. Treat it with 15 g of fast-acting carbohydrate, wait 15 minutes, retest, and tell your team — a repeated low usually means a dose or a meal needs adjusting.
Is this the same as the test that diagnosed my gestational diabetes?
No, and this is the most common mix-up on the subject. The glucose tolerance test uses much higher thresholds — 92 mg/dL fasting, 180 at one hour and 153 at two hours under IADPSG criteria — because you drank a large measured glucose load. Your daily targets are lower because you are measuring ordinary meals. Reading an OGTT result against your fasting target makes a normal test look terrifying, which is exactly why the diagnostic table is on this page.
Does this tool store my readings?
No. The check happens entirely in your browser and nothing you type is sent to us or saved. If you share a result, the reading travels inside the link itself — there is still no copy on our side, which is also why a shared link keeps working forever.
Keep exploring
Sources
- American Diabetes Association — Standards of Care, Management of Diabetes in Pregnancy
- NICE NG3 — Diabetes in pregnancy: management from preconception to the postnatal period
- Diabetes Canada — Clinical Practice Guidelines, Diabetes and Pregnancy
- ADIPS — Consensus Guidelines for the Testing and Diagnosis of Gestational Diabetes Mellitus in Australia and New Zealand
- GEDE — Grupo Español de Diabetes y Embarazo, Asistencia a la gestante con diabetes
- CNGOF — Recommandations pour la pratique clinique : le diabète gestationnel
- DSOG — Dansk Selskab for Obstetrik og Gynækologi, Gestationel diabetes mellitus
- WHO — Diagnostic Criteria and Classification of Hyperglycaemia First Detected in Pregnancy
- ACOG Practice Bulletin — Gestational Diabetes Mellitus
This tells you how one reading compares to published targets. It is not a diagnosis and it cannot see the rest of your pregnancy. Always follow the targets and advice your own midwife, doctor or diabetes team have given you.
Content reviewed by Dalo Labs ApS · www.dalo.tech · Last updated August 2026