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install with bioconda Bioconda installs covtobed Codacy Badge

status License

a tool to generate BED coverage tracks from BAM files

Reads one (or more) alignment files (sorted BAM) and prints a BED with the coverage. It will join consecutive bases with the same coverage, and can be used to only print a BED file with the regions having a specific coverage range.

📖 Read more in the wiki - this is the main documentation source


  • Can read (sorted) BAMs from stream (like bwa mem .. | samtools view -b | samtools sort - | covtobed)
  • Can print strand specific coverage to check for strand imbalance
  • Can print the physical coverage (with paired-end or mate-paired libraries)

ℹ️ For more features, check the BamToCov suite.

covtobed example


📖 The complete documentation is available in the GitHub wiki.


Usage: covtobed [options] [BAM]...

Computes coverage from alignments

  -h, --help            show this help message and exit
  --version             show program's version number and exit
  --physical-coverage   compute physical coverage (needs paired alignments in input)
  -q MINQ, --min-mapq=MINQ
                        skip alignments whose mapping quality is less than MINQ
                        (default: 0)
  -m MINCOV, --min-cov=MINCOV
                        print BED feature only if the coverage is bigger than
                        (or equal to) MINCOV (default: 0)
  -x MAXCOV, --max-cov=MAXCOV
                        print BED feature only if the coverage is lower than
                        MAXCOV (default: 100000)
  -l MINLEN, --min-len=MINLEN
                        print BED feature only if its length is bigger (or equal
                        to) than MINLELN (default: 1)
  -z MINCTG, --min-ctg-len=MINCTG
                        skip reference sequences having size less or equal to MINCTG
  -d, --discard-invalid-alignments
                        skip duplicates, failed QC, and non primary alignment,
                        minq>0 (or user-defined if higher) (default: 0)
  --output-strands      output coverage and stats separately for each strand
  --format=CHOICE       output format



covtobed -m 0 -x 5 test/demo.bam


NC_001416.1     0       2       0
NC_001416.1     2       6       1
NC_001416.1     6       7       2
NC_001416.1     7       12      3
NC_001416.1     12      18      4
NC_001416.1     169     170     4
NC_001416.1     201     206     4

See the full example output from different tools 📂 here


  • To install with Miniconda:
conda install -c bioconda covtobed
  • Both covtobed, and the legacy program coverage are available as a single Docker container available from Docker Hub Docker build:
sudo docker pull andreatelatin/covtobed
sudo docker run --rm -ti andreatelatin/covtobed coverage -h
  • Download Singularity image by singularity pull docker://andreatelatin/covtobed, then:
singularity exec covtobed.simg coverage -h

Startup message

When invoked without arguments, covtobed will print a message to inform the user that it is waiting for input from STDIN. To suppress this message, set the environment variable COVTOBED_QUIET to 1.


covtobed is generally faster than bedtools. More details are in the benchmark page.

Requirements and compiling

This tool requires libbamtools and zlib.

To manually compile:

c++ -std=c++11 *.cpp -I/path/to/bamtools/ -L${HOME}/path/to/lib/ -lbamtools -o covtobed

Issues, Limitations and how to contribute

  • This program will read the coverage from sorted BAM files. The CRAM format is not supported at the moment.
  • If you find a problem feel free to raise an issue, we will try to address it as soon as possible
  • Contributions are welcome via PR.


This tools uses libbamtools by Derek Barnett, Erik Garrison, Gabor Marth and Michael Stromberg, and cpp-optparse by Johannes Weißl. Both tools and this program are released with MIT license.


Giovanni Birolo (@gbirolo), University of Turin, and Andrea Telatin (@telatin), Quadram Institute Bioscience.

This program was finalized with a Flexible Talent Mobility Award funded by BBSRC through the Quadram Institute.


If you use this tool, we would really appreciate if you will cite its paper:

Releases after 1.3 (inclusive):

Giovanni Birolo, Andrea Telatin, BamToCov: an efficient toolkit for sequence coverage calculations, Bioinformatics, 2022

Releases up to 1.2:

Birolo et al., (2020). covtobed: a simple and fast tool to extract coverage tracks from BAM files. Journal of Open Source Software, 5(47), 2119,