Blood Pressure 166 Over 44–160: Which Are OK?
With an upper value of 166, the answer depends on your lower number. Here are all readings, sorted by what they mean.
On its own, a systolic (upper) value of 166 mmHg is Hypertension stage 2 by the international categories (2023 ESH guideline) and Stage 2 hypertension under the 2025 AHA/ACC guideline. The worse of your two numbers decides the category, so a raised diastolic (lower) value moves a 166 reading up: from 166/110 it counts as stage 3. Readings below 166/106 have a pulse pressure above 60 mmHg — a wide gap that is common after 60 and worth mentioning to your doctor.
Hypertension stage 2 166/44 to 166/109
- 166/44 ↓
- 166/60
- 166/61
- 166/62
- 166/63
- 166/64
- 166/65
- 166/66
- 166/67
- 166/68
- 166/69
- 166/70
- 166/71
- 166/72
- 166/73
- 166/74
- 166/75
- 166/76
- 166/77
- 166/78
- 166/79
- 166/80
- 166/81
- 166/82
- 166/83
- 166/84
- 166/85
- 166/86
- 166/87
- 166/88
- 166/89
- 166/90
- 166/91
- 166/92
- 166/93
- 166/94
- 166/95
- 166/96
- 166/97
- 166/98
- 166/99
- 166/100
- 166/101
- 166/102
- 166/103
- 166/104
- 166/105
- 166/106
- 166/107
- 166/108
- 166/109
↓ = the lower number is below 50: these readings count as stage 2 by the upper number, but the low lower number needs checking — see each page.
Hypertension stage 3 166/110 to 166/160
- 166/110
- 166/111
- 166/112
- 166/113
- 166/114
- 166/115
- 166/116
- 166/117
- 166/118
- 166/119
- 166/120
- 166/121
- 166/122
- 166/123
- 166/124
- 166/125
- 166/126
- 166/127
- 166/128
- 166/129
- 166/130
- 166/131
- 166/132
- 166/133
- 166/134
- 166/135
- 166/136
- 166/137
- 166/138
- 166/139
- 166/140
- 166/141
- 166/142
- 166/143
- 166/144
- 166/145
- 166/146
- 166/147
- 166/148
- 166/149
- 166/150
- 166/151
- 166/152
- 166/153
- 166/154
- 166/155
- 166/156
- 166/157
- 166/158
- 166/159
- 166/160
What to do with a reading of 166 over …
Measure at home for 7 days, morning and evening, and take the average to your doctor. A home average of 135/85 or more confirms high blood pressure. From 166/110 the lower number makes it stage 3: sit quietly for 5 minutes and measure again; if it stays at 110 or higher, contact a doctor the same day, and call 911 (US) or your local emergency number with chest pain, shortness of breath, back pain, numbness or weakness, vision or speech problems, confusion or a severe headache. A lower number below 50 (from 166/44 down) is clearly low: measure again, and if it is confirmed or you feel dizzy, faint or confused, contact a doctor the same day. Keep your readings in a free blood pressure log and read how to measure correctly.
Sources: ESH 2023 guideline · AHA/ACC 2025 guideline.