Which Newick features does this editor read?

Nested parentheses with labels and branch lengths, such as ((A:1,B:2)X:1,C:3)R; including unquoted labels, single-quoted labels like 'Homo sapiens' (write a quote inside one as ''), lengths such as 0.25, .5 or 1e-4, and bracketed comments such as NHX or BEAST annotations, which are kept. It opens one tree at a time and adds a missing final semicolon. Negative branch lengths are refused.

How does rerooting work, and does it change branch lengths?

Select a node and press Reroot here. With Middle of the branch above, the new root sits halfway along the branch above that node, which becomes two equal halves; with On this node, an internal node becomes the root. Either way the path length between every pair of tips stays the same. If the old root is left linking just two branches and joining them loses nothing, they become one branch with the lengths added, and the status line says what changed.

What happens to bootstrap or support values when I reroot?

A support value describes a branch, so after a reroot it has to move with that branch or it ends up on the wrong split. Set Internal labels are to Branch support and each value stays on its branch; with Names, each label stays on its node. Automatic chooses Branch support when the tree has internal labels below the root and all of them are numbers.

Can I add, delete or rename nodes by hand?

Yes. Select a node in the drawing or the node list, then change its label and branch length and press Apply label and length (or Enter). Add child tip adds a tip named new1 (then new2 and so on), Delete node removes the node and everything below it, and Collapse node removes an internal node and joins its branches to the node above, adding its length to each branch that has one. Rotate children and Ladderize change only the drawing order. Undo covers up to 50 steps.

Why is my Newick rejected?

The message gives the line and column and what to change: a parenthesis that is never closed or has no partner, a label with spaces that needs single quotes, a missing comma between sister nodes, a branch length that is negative or not a number, or text after the final semicolon. Show the error in the text puts the cursor there, and the last valid tree stays on screen, marked, until the text reads again.

How big a tree can it open?

Up to 1 MB of Newick text and 2,000 tips, nested at most 3,000 levels deep; larger input is refused with a message rather than cut short. The PNG export refuses a drawing too large for browsers to draw reliably and says so, while the SVG has no such limit.

Does it build a tree from my sequences or identify species?

No. It draws and edits the tree you supply. It does not align sequences, infer relationships, look up a taxonomy or check that labels name real organisms.

Where is my tree kept?

In this browser once you change something, and in any file you download; nothing is uploaded. Save project JSON keeps the Newick text and the drawing settings in a file that Open project JSON brings back, and Start over at the top of the page removes the copy kept in this browser.

Phylogenetic tree maker

Paste or open a tree in Newick format and it is drawn as you type: rectangular, circular or radial, with branch lengths to scale or ignored. Select any node to rename it, change its branch length, add or delete tips, collapse it into the node above, colour its clade or reroot the tree there. Rerooting keeps the path length between every pair of tips, and a setting keeps support values on their branches instead of their nodes. Syntax errors name the line and column, labels, lengths and bracketed comments are kept as written, and the tree exports as Newick, SVG, PNG or a project file without leaving this browser.

newick20 characters

Newick text (up to 1 MB and 2,000 tips)

Open Newick file

Valid Newick: 3 tips, 2 internal nodes.

This is an example tree with placeholder labels. Paste your own Newick above, or open a file.

treelengths to scale

Show internal labelsShow branch lengthsText sizeLine width

Nodes in tree order

Select a node in the list above or in the drawing to rename it, set its branch length, colour its clade or reroot the tree there.

Open project JSON

Tips: 3

Internal nodes: 2

Tree height: 3

Branch lengths: all present

Validated Newickwhat Download Newick saves
((A:1,B:2)X:1,C:3)R;
Path lengthbetween two tips
First tipSecond tipPath length: 5 over 3 branches

The tree as text

Rectangular tree with 3 tips and 2 internal nodes, rooted at R, branch lengths drawn to scale. Each line lists one node's branches in drawing order.

R has node X at length 1 and tip C at length 3. X has tip A at length 1 and tip B at length 2.

In the node list the arrow keys move through every node, and the fields under the list edit the selected node. Clicking a label or a dot in the drawing selects it too. Rerooting on the middle of a branch splits that branch into two equal halves, so every path length between tips stays the same.

When internal labels are support values, set Internal labels are to Branch support so a reroot keeps each value on its branch. Clade colours are written into the Newick as [&!color=#rrggbb] comments. This browser keeps the tree and the drawing settings once you change something; Save project JSON keeps them in a file that Open project JSON brings back.

Common questions

Which Newick features does this editor read?: Nested parentheses with labels and branch lengths, such as ((A:1,B:2)X:1,C:3)R; including unquoted labels, single-quoted labels like 'Homo sapiens' (write a quote inside one as ''), lengths such as 0.25, .5 or 1e-4, and bracketed comments such as NHX or BEAST annotations, which are kept. It opens one tree at a time and adds a missing final semicolon. Negative branch lengths are refused.
How does rerooting work, and does it change branch lengths?: Select a node and press Reroot here. With Middle of the branch above, the new root sits halfway along the branch above that node, which becomes two equal halves; with On this node, an internal node becomes the root. Either way the path length between every pair of tips stays the same. If the old root is left linking just two branches and joining them loses nothing, they become one branch with the lengths added, and the status line says what changed.
What happens to bootstrap or support values when I reroot?: A support value describes a branch, so after a reroot it has to move with that branch or it ends up on the wrong split. Set Internal labels are to Branch support and each value stays on its branch; with Names, each label stays on its node. Automatic chooses Branch support when the tree has internal labels below the root and all of them are numbers.
Can I add, delete or rename nodes by hand?: Yes. Select a node in the drawing or the node list, then change its label and branch length and press Apply label and length (or Enter). Add child tip adds a tip named new1 (then new2 and so on), Delete node removes the node and everything below it, and Collapse node removes an internal node and joins its branches to the node above, adding its length to each branch that has one. Rotate children and Ladderize change only the drawing order. Undo covers up to 50 steps.
Why is my Newick rejected?: The message gives the line and column and what to change: a parenthesis that is never closed or has no partner, a label with spaces that needs single quotes, a missing comma between sister nodes, a branch length that is negative or not a number, or text after the final semicolon. Show the error in the text puts the cursor there, and the last valid tree stays on screen, marked, until the text reads again.
How big a tree can it open?: Up to 1 MB of Newick text and 2,000 tips, nested at most 3,000 levels deep; larger input is refused with a message rather than cut short. The PNG export refuses a drawing too large for browsers to draw reliably and says so, while the SVG has no such limit.
Does it build a tree from my sequences or identify species?: No. It draws and edits the tree you supply. It does not align sequences, infer relationships, look up a taxonomy or check that labels name real organisms.
Where is my tree kept?: In this browser once you change something, and in any file you download; nothing is uploaded. Save project JSON keeps the Newick text and the drawing settings in a file that Open project JSON brings back, and Start over at the top of the page removes the copy kept in this browser.

Displays supplied relationships; does not infer evolution, identify organisms, perform medical analysis or fetch a taxonomy database.