View NWK files in your browser
The way nearly every phylogenetics tool writes a tree. Open one right here drawn as a tree, with no FigTree. Nothing leaves your device.
Or drop it anywhere on this page
What you'll see
Your tree opens drawn with its branch lengths, rectangular or circular, its support by each clade.
- Rectangular or circular • Branch lengths, a scale and support
- Fold a clade • A click on its node
- Find a name • Every match marked
- Export • Save as SVG, PNG or Newick
About NWK
The Newick format was agreed in 1986 by the authors of the main phylogenetics programs over dinner at Newick's, a seafood restaurant in New Hampshire, and Joseph Felsenstein's PHYLIP made it the standard. RAxML, IQ-TREE, FastTree, PhyML and MEGA write their trees in it, as .nwk, .tre, .tree or .treefile.
A tree is one line of nested brackets: (A:0.1,B:0.2)90:0.05 groups A and B, with each branch's length after a colon and a support value, like a bootstrap, after the bracket that closes a clade. Names can be quoted, and BEAST and others add notes in square brackets.
Filepeek reads it in your browser and draws the tree, rectangular with its branch lengths and a scale, or circular, with each clade's support by its node. A click on a node folds its clade into a triangle, Find marks the names that match, and Export saves the tree as SVG, PNG or Newick.
Newick tree
.nwk • .newick • .tre
Format
- MIME type
- text/x-newick
- Made by
- Joseph Felsenstein and the authors of the main phylogenetics programs, for PHYLIP
- Released
- 1986
Inside the file
- Clades
- Nested brackets
- Branch lengths
- After a colon
- Support
- After a clade's bracket
- Written as
- One line of text
Opens in every browser
Filepeek opens Newick files in Chrome, Edge, Firefox and Safari, trees of thousands of tips included. On their own, browsers download them or show them as text.
- YouChromeOpens through Filepeek
- YouEdgeOpens through Filepeek
- YouFirefoxOpens through Filepeek
- YouSafariOpens through Filepeek
Apps that open NWK
- WindowsFigTree, free • MEGA and Dendroscope
- MacFigTree, free • Dendroscope
- iPhone and iPadNo app opens it
- AndroidNo app opens it
Questions
How do I open a Newick tree without FigTree?
Drop it on this page or choose Peek an NWK. The tree opens drawn in your browser, on a phone too, with nothing to install.
What are the numbers on the nodes?
Support values: bootstrap percentages from RAxML or IQ-TREE, or posterior probabilities from MrBayes and BEAST. They show by each clade's node, and Support hides them.
Why does my .tre file open as text?
A .tre opens as a tree when it starts with a bracket, as Newick does, or with #NEXUS. Other programs name other files .tre too, and those open as their text.
Can I save the tree as a picture?
Yes. Choose Export, then Save the tree as SVG for papers and slides, or as PNG, with every clade open.