Temple-to-Temple: The One Measurement Nobody Tells You About
Temple length is the arm on your glasses. Temple-to-temple is the width of your head. They are different numbers, they are constantly confused, and only one of them decides whether a frame fits.
Published 2026-07-29 · 7 min read
W
Woolet Editorial Team
Eyewear fit & sizing · Woolet, wide-face eyewear since 2026
Published: 29 July 2026 · Last updated: 29 July 2026
Temple length is the arm of the glasses — usually 135–150 mm, the third number in a marking like 54□21-140. Temple-to-temple is the width of your head. They sound the same and are entirely different. Front width must match your temple-to-temple measurement; temple length only controls how far back the arm reaches.
This confusion costs people money. Someone measures their head at 158 mm, finds a frame marked 54□21-150, sees the largest number matches roughly, and buys it. The arm is long. The front is 135 mm. It arrives and it pinches.
So before anything else: the third number on your frame is not a width. It has never been a width.
Two measurements, one word
|
Temple length |
Temple-to-temple |
| What it measures | The side arm of the frame, hinge to tip | Your head, side to side |
| Belongs to | The frame | You |
| Typical range | 135–150 mm | 130–170 mm |
| Where you find it | Printed inside the arm, third number | Ruler across your head, or a FitLens scan |
| Decides fit? | Comfort behind the ear only | Yes — it sets required front width |
Temple length: what the numbers actually do
Temple length is measured from the centre of the hinge screw, along the arm, around the bend and to the tip. It determines where the arm turns down. Too short and the bend lands in front of the ear, pressing into the side of the head. Too long and the tip slides past the ear and the frame slips forward.
| Temple length |
Who it fits |
Notes |
| 135 mm | Small adult and youth frames | Common on XS/S fronts. Bends early. |
| 140 mm | The default for most adults | Paired with 132–142 mm fronts. If a shop has one length in stock, it is this. |
| 145 mm | Larger heads, ears set further back | The usual upgrade when a 140 mm arm bends too early. |
| 150 mm | Long-skulled or high-circumference heads | Rare in stock. Often special order. |
103 mm + 52 mm drop
Woolet 007 / 009 | 155–161 mm faces | Different convention — see below. Effective reach is comparable to 145–150 mm. |
Why Woolet publishes 103 mm
Both signature frames — the 007 Round (54□21, front 158 mm, lens height 42 mm, front height 52 mm) and the 009 Soft-Square (51□20, front 158 mm, lens height 45 mm, front height 54 mm) — list a 103 mm temple and a 52 mm tip drop.
That 103 mm is the straight section from hinge to the start of the bend. The conventional marking on a mass-market frame folds the whole curved path into one number, which is why it reads 140 or 145. Add Woolet's 103 mm straight run to the 52 mm drop and the arm reaches as far back as a conventionally marked 145–150 mm temple.
We publish it split because on a wide front the two parts do different jobs. The straight run has to clear a wider skull before it turns; the drop has to sit behind an ear that is further back than the average. Reporting a single fused number hides which of the two is short when a frame does not fit — and on a 158 mm front that distinction matters.
Temple length and head circumference
Head circumference and temple-to-temple width are correlated but not interchangeable. A head can be wide and short front-to-back, or narrow and long. Circumference above roughly 59 cm generally means you need a 145 mm arm or longer, regardless of width, because the ears sit further back along the skull.
The practical consequence: it is entirely possible to need a 158 mm front with a standard 140 mm arm, or a 140 mm front with a 150 mm arm. These are independent dimensions and should be chosen independently. Length reference pages by measurement: 140 mm · 145 mm · 150 mm.
FitLens · 20 seconds, phone camera
Temple-to-temple is the number that decides whether a frame fits, and it is awkward to measure on yourself. FitLens reads it from your phone camera in about twenty seconds, together with your bridge width.
Get your number in 20 seconds
How to measure both, properly
Temple length (the frame). Lay one arm flat on a table. Measure from the centre of the hinge screw along the arm; when you reach the bend, follow the curve to the tip rather than measuring in a straight line. Round to the nearest 5 mm — that is the granularity the industry works in.
Temple-to-temple (your face). Stand square to a mirror. Hold a ruler flat and level across the widest part of your head, just above and in front of the ears — not across your cheekbones, which reads 8–15 mm narrow. Read the millimetres. The full calibrated method, including the credit-card photo reference, is in how to measure your face width for glasses.
Frame width vs temple length, one last time
If a frame hurts at the temples, the front is too narrow — temple length is irrelevant to that problem, and buying a longer arm will not help. If a frame hurts behind the ear, or slides down your nose while sitting level at the sides, temple length or its bend is the culprit and an optician can fix it. The diagnostic table in glasses too tight on the side of your head covers every combination.
FAQ
How do I measure temple length for glasses?
Lay one arm flat and measure from the centre of the hinge screw, along the arm, around the bend and out to the tip. Standard lengths are 135, 140, 145 and 150 mm. If the arm curves down behind the ear, follow the curve rather than measuring straight — that is the convention printed on the frame.
What does temple length mean on glasses?
It is the length of the side arm from hinge to tip in millimetres, the third number in a marking like 54□21-140. It controls how far back the frame reaches before it turns down behind the ear. It says nothing about how wide the frame is across your face.
What is the difference between 140 and 145 temple length?
Five millimetres of reach. A 145 mm arm places the bend 5 mm further back, which helps if your ears sit further back on your skull or if a 140 mm arm bends before it clears the ear and digs in. It does not make the frame wider across the front — a common and expensive misunderstanding.
What does temple-to-temple mean?
It is your own face measurement: the distance across the widest part of your head, just above and in front of the ears, measured in millimetres. It is the number a frame's total front width should match within about 3 mm. Average is under 140 mm; 155 mm and above is a wide face.
Why is the Woolet temple length only 103 mm?
Because Woolet publishes the straight arm section to the start of the bend, not the total path length around the drop. Adding the 52 mm tip drop gives an effective reach comparable with a conventional 145–150 mm marking. Different convention, same fit — it is listed alongside the tip drop for exactly that reason.
Related articles