Specific calculators, planners, and explainers for jobs that usually get buried in forums.
HTML-first, no account wall
Shareable URLs and direct outputs
Welding · Decoder
Welding symbol decoder
Turn common welding symbols into plain English, see the callout drawn live, and stop guessing whether the weld is on the arrow side, the other side, or both.
What this helps with
Most weld-symbol confusion is not about one isolated icon. It is about how several marks combine on the same reference line.
- Shows the reference line, arrow, tail, contour mark, finish letter, and supplementary marks together.
- Explains the difference between arrow-side and other-side placement in plain language.
- Keeps the common print-reading cases close at hand instead of forcing a full standards lookup every time.
Important: this is a print-reading aid, not a code-book replacement. Company standards, ISO variants, and project notes can override the common AWS-style defaults used here.
Common symbols at a glance
Fillet
Triangular symbol for T-joints, lap joints, and corner joints.
Square groove
Parallel plates with little or no edge prep, often for tighter root fits.
V-groove
Both members are beveled to form a V before welding.
Bevel groove
Only one member is beveled; the arrow points at the member to prepare.
J-groove
Curved J-shaped prep on one side to reduce filler volume versus a V.
Plug or slot
A filled hole or slot used to tie overlapping parts together.
Spot
A round spot weld callout, often paired with pitch spacing.
Seam
A seam weld symbol for continuous or intermittent resistance seam welds.
Backing
Backing material or weld metal supporting the root side of a groove weld.
Melt-through
Shows visible root reinforcement or required penetration on the far side.