Jacob's Ladder Quilt Block — Cutting Chart for Any Size
2 fabrics · Difficulty 4 of 5
Jacob's Ladder is a 4×4 block of 24 pieces. Cut sizes for 4″, 8″, 12″, 16″, 20″ are below; for any other size it divides into cleanly, type the size and the chart recomputes.
Set the finished sizeAt a glance
- Grid
- 4×4
- Pieces you cut
- 16 — subcutting turns them into the 24 in the sewn block
- Difficulty
- 4 of 5 — experienced How this is scored
Set the size
Nearest sizes that cut cleanly:
- Squares — Fabric A
- 3½″
- Squares — Background
- 3½″
- Squares for half-square triangles — Fabric A
- 3⅞″
- Squares for half-square triangles — Background
- 3⅞″
Reading focusTriangle-unit fields cross the checker structure diagonallyhalf-square-triangle unit
- Construction lattice
- 4 modules wide × 4 modules high
- Unit mix
- half-square-triangle unit, square
- Piece count
- 16 to cut · 24 in the diagram
Cut these pieces
Column headings are the FINISHED block size — the size it will be once it is sewn. Every number in the table is the size to CUT, which includes ¼″ of seam allowance on each edge. Rows that are subcut on a diagonal are cut larger still, so the allowance survives the extra cuts.
Scroll sideways to see every size.
| Patch | 4″ | 8″ | 12″ | 16″ | 20″ |
|---|---|---|---|---|---|
| Squares — Fabric ACut 4 | 1½″ | 2½″ | 3½″ | 4½″ | 5½″ |
| Squares — BackgroundCut 4 | 1½″ | 2½″ | 3½″ | 4½″ | 5½″ |
| Squares for half-square triangles — Fabric ACut 4, cut once on the diagonal | 1⅞″ | 2⅞″ | 3⅞″ | 4⅞″ | 5⅞″ |
| Squares for half-square triangles — BackgroundCut 4, cut once on the diagonal | 1⅞″ | 2⅞″ | 3⅞″ | 4⅞″ | 5⅞″ |
Read the block
Match each fabric letter in the diagram to the same fabric name in the cutting table. The caption describes the generated geometry in text.
Fabrics in this block
- A — gold
- BG — background
Which sizes divide cleanly
Scroll sideways to see every column.
| Grid | Divides cleanly at | The first few sizes |
|---|---|---|
| 2×2 | every 1″ | 1″, 2″, 3″, 4″, 5″, 6″ … |
| 3×3 | every 1½″ | 1½″, 3″, 4½″, 6″, 7½″, 9″ … |
| 4×4this block | every 2″ | 2″, 4″, 6″, 8″, 10″, 12″ … |
| 5×5 | every 2½″ | 2½″, 5″, 7½″, 10″, 12½″, 15″ … |
| 7×7 | every 3½″ | 3½″, 7″, 10½″, 14″, 17½″, 21″ |
- A 5-patch block at 12″ would need 2.4″ units, which is not a mark on any ruler. Try 10″ or 12½″ instead — Sister's Choice is the 5-patch block on this site.
- A 7-patch block at 12″ would need 1.714…″ units, which is not a mark on any ruler. Try 10½″ or 14″ instead — Bear's Paw is the 7-patch block on this site.
More about the sizes that do not divide cleanly
The sizes in between
Every whole-inch Jacob's Ladder size from 4″ to 20″ can be cut accurately on its 4×4 grid.
These sizes divide cleanly but sit between the main chart's columns — the same computed cuts, published here so they exist on paper too. Any other clean size still computes in the size input above.
Column headings are the FINISHED block size — the size it will be once it is sewn. Every number in the table is the size to CUT, which includes ¼″ of seam allowance on each edge. Rows that are subcut on a diagonal are cut larger still, so the allowance survives the extra cuts.
Scroll sideways to see every size.
| Patch | 6″ | 10″ | 14″ | 18″ |
|---|---|---|---|---|
| Squares — Fabric ACut 4 | 2″ | 3″ | 4″ | 5″ |
| Squares — BackgroundCut 4 | 2″ | 3″ | 4″ | 5″ |
| Squares for half-square triangles — Fabric ACut 4, cut once on the diagonal | 2⅜″ | 3⅜″ | 4⅜″ | 5⅜″ |
| Squares for half-square triangles — BackgroundCut 4, cut once on the diagonal | 2⅜″ | 3⅜″ | 4⅜″ | 5⅜″ |
About this block
- Pieces in the finished block
- 24
- Unit types
- half-square-triangle unit, square
- Divides cleanly at
- 2″, 4″, 6″, 8″, 10″, 12″, 14″, 16″, 18″ and 20″ finished.
- Also known as
- Road to California, Railroad, Stepping Stones, Wagon Tracks, Underground Railroad, Golden Stairs
- Attribution
- Marie Webster, Quilts: Their Story and How to Make Them (1915)
- Fabric for one 12″ block
- ½ yd total, rounded up to the nearest ⅛ yard, assuming 40″ of usable width.
Every triangle unit faces the same way — not one of them turns — so the diagonal movement comes from repetition and reversed fabrics, not rotation. Opposite quadrants pair up: checkerboard squares across one diagonal, triangle units across the other. Watch the dark path as the block grows; a reversed unit breaks the run, and is far better caught before the quadrant seams lock it in.
Piecing order
Make the 8 half-square-triangle units.
Lay out row 1 of 4 and sew its pieces together, left to right.
Lay out row 2 of 4 and sew its pieces together, left to right.
Lay out row 3 of 4 and sew its pieces together, left to right.
Lay out row 4 of 4 and sew its pieces together, left to right.
Join the 4 rows, matching the seams.
Cutting oversize
The chart gives the standard cut sizes, nothing padded. Some quilters cut this block's triangle units a little oversize and trim back — published allowances genuinely disagree on how much, so the range with its sources is on how to square up a quilt block.
History
Ruth Finley's 1929 Old Patchwork Quilts named this family Railroad Crossing and pictured a nine-patch variation she called Underground Railroad — that name is a genuine 1929 print fact. The story that the block signalled escape routes is not: Barbara Brackman traces the 'quilt code' legend to modern fiction and has written plainly against repeating it as history. The first book publication under the Jacob's Ladder name is Marie Webster's 1915 Quilts: Their Story and How to Make Them.
Sources: Barbara Brackman — Underground Railroad; Barbara Brackman — Quilt Code Persists.
Common questions
What size can I make Jacob's Ladder?
Any size it divides cleanly: 2″, 4″, 6″, 8″, 10″, 12″, 14″, 16″, 18″ and 20″ finished. The chart above carries 4″, 8″, 12″, 16″, 20″ ready-worked, and the size input computes any other clean size without you doing arithmetic — every value computed by Quilt Block Atlas, none transcribed.
How many pieces are in a Jacob's Ladder block?
24 pieces make up the sewn block, but you cut 16. The difference is method: triangle units are cut as squares and subcut, so the chart's quantities are what your rotary cutter produces, not what you count in the diagram.
What sizes does a 4×4 block divide into cleanly?
2″, 4″, 6″, 8″, 10″, 12″, 14″, 16″, 18″ and 20″ finished. The step is half the grid this block's cutting sizes are computed on, and the clean-size table above marks this block's row with the other families beside it.
Is Jacob's Ladder good for a beginner?
Not as a first block — it scores 4 of 5, experienced, on this site's computed scale: 24 pieces, with the half-square-triangle unit as its hardest unit. The scoring rule, and every block ranked by it, is on the difficulty page linked above.
How do finished size, sewn unfinished/trim size, and starting cut size differ?
Finished size is 12″ after the block is sewn into surrounding seams. Its sewn unfinished/trim size is 12½″ before those outer seams, derived with the plain-square allowance. Starting cut size is the method-specific input listed in the chart. Starting cut size equals the unfinished outer target only for a plain square or rectangle workflow; it is not generally the same for pieced triangle units.
Keep going
Related blocks
Where this block appears
Calculators for this block
- Quilt block grid calculator
- Half square triangle calculator
- Quilt top size calculator
- Fabric yardage calculator
Reference
Before you print
Measure this square before you cut. It must be exactly 1 inch. If it isn't, your printer scaled the page — reprint at 100% or "Actual size", not "Fit to page".