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How Long Should Picture Wire Be? Slack and Hook Drop
The length of a picture wire decides how far below the frame’s top the hook ends up. Pulled up by a single nail, the wire forms a triangle, and its peak — not the screw eyes — is the point that rests on the hook. A longer wire peaks higher; a tight one barely rises at all. This guide shows how to work that out before you drill.
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The wire makes a triangle
Each half of the wire runs from a screw eye up to the hook, so the two halves and the line between the eyes make a triangle. The longer the wire compared with the gap between the eyes, the taller that triangle — and the higher the peak sits on the back of the frame.
The formula
Halve the wire and halve the gap between the anchors. The peak rises above the anchors by the square root of (half the wire squared minus half the gap squared). Take that rise off the anchors’ distance below the top, and what is left is the drop from the frame’s top to the hook.
Measure the wire between the anchors only — not the twisted ends wrapped around them.
Worked examples
| Anchors apart | Anchors below top | Wire | Peak rises | Hook below the top |
|---|---|---|---|---|
| 24 in | 6 in | 25 in | 3.5 in | 2.5 in |
| 24 in | 6 in | 26 in | 5 in | 1 in |
| 24 in | 6 in | 30 in | 9 in | Peak shows 3 in above the frame |
| 40 cm | 18 cm | 50 cm | 15 cm | 3 cm |
How much slack to leave
- Leave enough that the peak stays a little below the frame’s top edge, so the wire and hook are hidden.
- Too much slack lets the top of the frame tip forward off the wall.
- Too little puts a lot of tension on the anchors and makes the frame hard to level.
- Screw eyes about a quarter to a third of the way down the frame are a common place to start.
Checking a frame that is already wired
- Lay the frame face down.
- Measure between the two anchors and how far they sit below the top edge.
- Pull the wire up at its middle toward the top, as a nail would, and measure from that point to the top edge.
- Compare it with the formula; if the peak reaches the top edge, shorten the wire.
Picture Wire Length FAQ
- How tight should picture wire be?
- Tight enough that, pulled up at the middle, the wire’s peak stays a little below the frame’s top edge. A 26 in wire between screw eyes 24 in apart rises 5 in.
- Why does a longer picture wire change the nail position?
- A longer wire forms a taller triangle when pulled up, so its peak sits higher on the frame and the nail has to go higher to put the frame in the same place.
- Can picture wire show above the frame?
- Yes, if it is long enough that its peak rises past the top edge. With anchors 6 in down and 24 in apart, a 30 in wire peaks 3 in above the frame.
- Do I measure the wire from knot to knot?
- Measure the length between the two anchors, not the ends twisted around them, because only that length forms the triangle.
- Where should screw eyes go on a frame?
- About a quarter to a third of the way down each side is a common starting point, equally placed so the frame hangs level.
Related guides
- Wire vs D-Rings vs SawtoothHow picture wire, D-rings, and sawtooth hangers differ: how each sits on the hook, how level it stays, how to measure its drop, and which suits a frame.
- Hanging With Two HooksHang a frame level on two hooks: set both at the same height, space them as far apart as the D-rings, and find their distance from each frame edge.
Open the tool
Jump into Picture Hook / Nail Offset Calculator when you are ready to process your files.
