Annotated Heatmap Generator - Free Online Table Heatmap Maker
Use Annotated Heatmap Generator - Free Online Table Heatmap Maker
All GotoKit tools run directly online, no download required.
Upload a wide-table CSV template to generate an annotated table heatmap: a diverging color scale shows the numeric distribution of a 2D matrix, every cell is labeled with its value, and a vertical color bar with ticks sits on the right. Three color themes (classic reference, rainbow, Morandi), light / dark canvas, and PNG / SVG export.
About this tool
Heatmaps excel at exposing patterns, yet bare color blocks hide the exact numbers. This table heatmap fills every cell with color and prints the value inside it — a diverging scale runs from zero to positive and negative extremes, negative in blues and positive in reds, with a ticked vertical color bar on the right. Built for correlation matrices, expression data and survey scores where you read color and number together.
- Export crisp PNG / SVG you can keep editing
- Multiple built-in themes, one-click switch
- Light and dark canvas support
- Free, no watermark, no limits
Compared with general charting workflows
| Aspect | This tool | Typical alternative |
|---|---|---|
| Visual direction | Optimized for a specific chart grammar | More general, but more setup |
| Export | Fast PNG/SVG export first | More formats, but heavier workflow |
| Best fit | Slides, landing pages, and social visuals | Building bespoke analytical charts from scratch |
Docs
What is an annotated heatmap?
An annotated heatmap (also called a table heatmap or labeled matrix heatmap) shows the numeric distribution of a 2D matrix: rows and columns are the categories of two dimensions, each cell’s color varies continuously with its value, and every cell is directly labeled with the exact number — so you can grasp the overall pattern at a glance and still read individual values precisely. When values can be negative and positive, a diverging color scale is used: cool colors for negatives, a light neutral tone at zero, warm colors for positives, with a vertical continuous color bar on the right as the legend. This tool faithfully reproduces the reference style: white background, thin white gaps between cells, dark rose axis text, and a vertical ticked color bar with an upright rotated title, plus rainbow and Morandi themes.
Features
- Template driven, WYSIWYG: no visualization skills needed — download the CSV template, fill in your data, upload, and get the heatmap
- Wide matrix layout: first row = X categories, first column = Y categories, top-left cell empty, numbers in the grid; 2
40 rows × 260 columns - Per-cell value labels: every cell shows its value; labels automatically switch to white on dark cells for readability
- Auto-rounded diverging scale: the scale diverges from 0 toward both ends, and the color bar range snaps to symmetric round ticks (e.g. ±60)
- Three color themes: classic reference (teal → ivory → orange → wine), rainbow (violet → blue → green → yellow → red), and Morandi (muted blue-gray → beige → terracotta), switchable from a dropdown
- Light / dark modes: switch canvas style in one click; dark mode brightens the palette for slides, reports, and web pages
- Multiple export formats: download high-resolution PNG (2x pixel ratio) or vector SVG
- Local privacy: all data is parsed and rendered locally in your browser, never uploaded to any server
Use cases
- Research and academia: gene expression matrices, correlation matrices, experiment-condition × metric result distributions
- Data analytics and BI: cross-dimensional views such as region × product or month × channel for sales, growth, or attainment
- Finance and risk: spread matrices by sector × tenor, factor-exposure heat distributions
- Operations and user research: activity by weekday × hour, conversion comparison by page × version
- Reports and presentations: add information-dense yet elegant matrix charts to slides, posters, and annual reports
If your values have no negative/positive meaning and you only compare magnitudes on one side, consider a single-hue triangular distribution heatmap instead; the annotated heatmap is best for matrix data that spans both signs and needs per-cell reading.
How to use
- Click “Download CSV template” to get the sample file
- Fill in your data: first row = X categories, first column = Y categories, top-left cell empty, numbers in the grid
- Click the upload area or drag and drop a CSV file onto the page
- The annotated heatmap is generated automatically; switch color themes and light / dark mode to preview
- Click “Download PNG” or “Download SVG” to save the image
Data format
| Position | Required | Description |
|---|---|---|
| First row | Yes | X category names (e.g. 1~36); the top-left cell stays empty |
| First column | Yes | Y category names (e.g. 1~20) |
| Grid cells | Yes | Numbers, positive or negative, integers or decimals |
Limits: 240 rows × 260 columns; all grid cells must be numeric. The scale diverges from 0 toward both ends, and the color bar range snaps to a symmetric round value based on the data’s maximum absolute value (e.g. ±60) with 7 ticks.
How to read this chart
Color carries direction and magnitude, but read the printed number for precision. Zero is the pivot: cells on one side are positive, the other negative, growing more saturated away from zero. To find outliers, scan rows and columns for sudden color jumps first, then confirm with the printed value.
About Gotokit
Gotokit is dedicated to providing simple, efficient, and beautiful online tools. This annotated heatmap generator is powered by the ECharts rendering engine — no sign-up required, ready to use, with all data processed locally to protect your privacy.
FAQ
What is the wide-table layout: X categories in the header row, Y categories in the first column, top-left cell empty?
A wide matrix layout: first row holds the X categories (top-left cell empty), first column holds the Y categories, and the grid cells hold the values. It supports 2~40 rows × 2~60 columns; values can be positive or negative, integers or decimals.
How is the color bar range determined?
The scale diverges from 0 toward both ends: the range takes the data's maximum absolute value and rounds up to a symmetric round number (e.g. data within ±47 snaps to ±50, within ±57 to ±60), producing 7 ticks so that 0 always maps to the neutral middle color.
Is this chart tool better for slides, reports, or social visuals?
All three can work, but each needs a different emphasis. Slides care about legibility, reports care about structure and annotation, and social visuals care about density and style. Tune colors, labels, and export size for the destination.
When should I export PNG instead of SVG?
PNG is usually better for slides, chats, or social sharing, while SVG is better if you need to keep editing, scale for print, or embed the graphic in a design system. If the target platform does not support SVG, export a higher-resolution PNG.
How is this different from a general charting tool?
These tools are optimized for a specific visual grammar, so you can get to a strong result faster. General charting tools are more flexible across many chart families, but usually take more setup and styling work.
Can I use this tool on mobile phones or tablets?
Most tools work in modern mobile browsers, but complex charts, larger files, and precision drag-and-drop tasks usually feel better on desktop. If speed and control matter, desktop is the safer choice.
Is this tool better for one-off tasks or recurring workflows?
It is strongest for fast one-off tasks, quick verification, and temporary exports. If you need long-term automation, team collaboration, or deeper integration, you will usually pair it with desktop software, scripts, or a larger system.
How can I get a better result on the first try?
Start with the built-in example or with the smallest realistic sample you have. Once the format, layout, and export look right, switch to the full dataset or final asset. This is usually the fastest way to catch formatting issues early.
More from Design
All Design toolsCircular Evidence Network Plot Generator
Generate a circular evidence network from independently entered patient totals and pairwise study counts in CSV. Node area shows patients and curve width shows studies, with local processing, light/dark mode and PNG/SVG export. No statistical analysis.
Pantone Color Picker
Pick any color and find the nearest Pantone reference instantly, with ready-to-copy HEX and RGB values for design and print workflows.
Color Wheel Studio
Explore colors with an interactive wheel, fine-tune HEX, RGB, HSL, and HSV values, and save palettes directly in your browser.
Color Scheme Generator
Generate color schemes from a base color using 7 harmony rules with live UI preview and export to HEX, Tailwind, or CSS variables.
Pantone + CMYK + RGB Print Palette
Professional print palette with 150+ Pantone swatches, 2-5 color combos, auto Pantone matching, real-time CMYK, and simulated coated-paper preview.
Gradient Art Generator
Create layered radial-gradient artwork with blend modes, random presets, and copy-ready CSS for modern backgrounds and hero sections.
Chord Diagram Generator - Free Online Circular Chart Maker
Read pair-wise relationships with a circular chord diagram: nodes ring the circle, arc length shows each node’s total flow, and ribbon width plus color encodes how strongly any two nodes connect. Made for migration, trade, calls or citations, with three color themes and PNG / SVG export.
Elegant Date Ring Bubble Chart
Map a full year of events onto a concentric date ring — months on the outer circle and days aligned inward — so each event floats as a soft gradient bubble over its own calendar cell. Sparse days and crowded holidays reveal themselves instantly in a refined, low-saturation palette with light / dark canvas and PNG / SVG export.
Dual Gradient No. 1 Nightingale Rose Chart
A Nightingale rose whose petals sweep outward in a symmetric ring, each one brushed with a two-tone gradient instead of a flat color. An optional year label sits at the center of the chart, and light / dark canvas styles come with PNG / SVG export.
Poster Two-Column Sankey Diagram Generator
A poster-grade two-column Sankey: left-side nodes take vivid colors while right-side nodes are shaded in weight-based grays, and every flow band carries its own name, value and share. The clean two-column layout is ready to drop into a poster, with light / dark canvas styles and PNG / SVG export.
Streamgraph Generator - Free Online River Chart Maker
A smooth streamgraph where every series stacks symmetrically around a baseline that sways with time, the stacked shapes undulating like shifting river channels. Ideal for comparing how the parts of a whole change together over the years; supports 2 to 16 series and 3 to 40 rows, with light / dark canvas and PNG / SVG export.
Morandi Streamgraph Generator - Free Online River Chart Maker
A streamgraph dressed in a Morandi blue-to-pink palette: low-saturation navy, blue-gray and dusty rose keep the layered river calm and easy on the eye, thin white seams separate every layer, and a top legend keys colors to series. For stacked trend views that still feel refined, with light / dark canvas and PNG / SVG export.
Error Band Chart Generator - Free Online Confidence Band Maker
A continuous error band chart: instead of a fixed shadow under the main line, a band hugs the line and changes width point by point, swelling in volatile periods and thinning in calm ones, so trend and uncertainty live in one frame. Classic off-white, rainbow and Morandi themes with light / dark canvas and PNG / SVG export.
Line Bubble Chart Generator - Free Online Log-Scale Bubble Chart Maker
A curved-stem bubble chart for timelines: each event sits on a year axis, a thin stem bows rightward off the bottom spine and lifts a translucent bubble, and a logarithmic Y axis keeps values across orders of magnitude (0.7 to 14) comparable in one frame while bubble size maps by square root. Five category colors, light / dark canvas and PNG / SVG export.
Morph Bubble Zoning Diagram Generator - Free Online Organic Bubble Diagram Maker
A Morph Bubble Zoning Diagram where child nodes fuse into their hub with Metaball surfaces instead of floating detached, labels run along each node’s outer arc, dashed links connect the bubbles, and a teal-to-green four-color palette keeps the cluster calm. Made for hub-and-member structures; light / dark canvas and PNG / SVG export included.
Scallop Chord Diagram Generator - Free Online Bipartite Chord Diagram Maker
A scallop-shaped bipartite chord diagram: group arcs along the bottom are weighted by total flow into unequal scallops, target nodes fan across the top in equal-width arcs, and the flows between them become thin ribbons bending along center-crossing Bézier curves, with radial labels that never tangle. Built for few-groups-to-many-targets bipartite data; light / dark canvas and PNG / SVG export.
Grouped Bar Chart with Error Bars Generator - Free Online Chart Maker
A grouped bar chart with error bars in the restrained academic style: two pastel-colored bars side by side, black I-shaped error bars on top, a full black axis frame and x labels rotated 45 degrees — a faithful reproduction of a paper-ready figure. Built for experimental group comparisons, with light / dark canvas and PNG / SVG export.
Ridgeline Plot Generator - Free Online Joy Plot Chart Maker
A ridgeline (joy) plot that stacks several distributions along their own horizontal baselines, peaks rising smooth and never overlapping, with a series name on the left of each row and a dot legend beneath — ideal for comparing the peaks and spread of many groups side by side. Up to 6 series and 400 rows, with light / dark canvas and PNG / SVG export.
Radial Stacked Bar Chart Generator - Free Online Circular Bar Plot Maker
A radial stacked bar chart (racetrack / circular bar plot) where each row of data becomes one concentric ring, split into stacked category arcs whose lengths stay proportional to the ring total — like laps of a track labelling each year’s composition. An italic total sits just beyond every arc end and a vertical square-marker legend keys the colors; light / dark canvas and PNG / SVG export included.
Curved Fan Story Sankey Diagram Generator
Recreate the reference style with fan-shaped sources, slanted event bars and curved character arcs. Map influence to ribbon width and export CSV-driven PNG or SVG charts.
Log-Scale Bubble Scatter Chart Generator
Upload a CSV to build a dual log-axis bubble scatter: bubble area encodes a third variable, colors follow your groups, and a dashed y=x line with R² / P / n annotations is added automatically. PNG and SVG export included.
Five-Stage Pastel Gradient Sankey Diagram Generator
A five-stage Sankey that renders source → transit → hub → channel → destination in one chart. Every node takes its own pastel color, ribbons blend a source-to-target gradient at low opacity, and slim nodes carry white pill labels on the inner columns. Three soft palettes, light / dark canvas and PNG / SVG export.
Dual-Tone Budget Flow Sankey Diagram Generator
A standard left-to-right layered dual-tone budget Sankey built on the ECharts sankey layout: the revenue side converges in cyan from the left, passes through the central pivot bar that fades from cyan to magenta, and the expenditure side then diverges to the right in magenta. Within each family, nodes are ranked by throughput across seven shades of light and dark — darker and thicker means larger, while pale slivers that thin to a line are the smallest items. Labels are tiered by column with automatic collision avoidance. Three dual-tone palettes, light / dark canvas and PNG / SVG export.
Energy Flow Sankey Diagram Generator
A free-depth energy flow Sankey that renders energy sources → conversion carriers → end uses in one chart, in UK DECC style. Every node takes an earthy multi-hue color, ribbons blend a source-to-target gradient at ~0.2 low opacity, and all node labels sit to the right of their bars with no background. Three palettes, light / dark canvas and PNG / SVG export.
Metabolite–Pathway Enrichment Sankey Generator
Render a two-column metabolite → pathway enrichment Sankey plus a matching right bubble panel in one chart. Ribbons use one flat light-gray tone at ~0.6 opacity so overlaps darken; every label sits to the left of its bar, right-aligned and vertically centered with no pill; ~50 pastel metabolites feed 11 gem-toned pathways; the bubble panel aligns row-by-row, x = -Log(Pvalue), area = Count, red shade = Hit Ratio. Light / dark canvas and PNG / SVG export.
Four-Stage Decision Sankey Diagram Generator
A four-column Sankey that renders the whole funnel at once — origin, destination, decision, then breakdown by origin. Volume layers in from the left, the right side splits it into accepted-versus-rejected comparison bars per source, and a year badge plus three palettes complete the academic poster look for review, approval or admission flows.
Three-Column Influence Sankey Diagram Generator
Chain situation type → scene → character into one influence-flow diagram: ribbon width is the value itself, so the thicker the scene the bigger its pull on the outcome. Right-column nodes inherit the colour of their largest source category, and the bottom legend reads your own CSV node names — swap in your data and the whole chart re-skins instantly. Includes in-chart title and caption, light / dark canvas and PNG / SVG export.
Triangular Distribution Matrix Heatmap Generator
Lay out a frequency matrix — how many days each category spends in every value bin — as a stepped triangular heatmap. Cell color encodes frequency while IQR ranges, median dots and mean crosses are drawn automatically, revealing skew and spread at a glance. Three palettes, light / dark canvas and PNG / SVG export.
Circos Gradient Ribbon Chord Diagram Generator
A Circos-style chord diagram split into warm and cold camps: warm nodes and cold nodes each form a continuous arc, and the link between them becomes a ribbon that gradients from one end’s color to the other’s. Whole-camp flows are legible at a glance for matrices such as genomics, networks or ecology; dark mode and PNG / SVG export included.
Bubble Chord Diagram Generator - Circular Collaboration Network
A bubble chord diagram places paired relationships around one big circle: each node is a bubble whose size shows the node scale and whose fill walks an aqua-to-blue colormap for strength; links bow toward the center with thickness proportional to the flow value, while node names radiate outside the ring. Built for collaboration networks, supply-chain dependencies and inter-team flows where each node also carries metrics, still legible around 30 nodes; dark mode and PNG / SVG export.
Radial Arc Flow Diagram Generator
A radial arc flow diagram for country-to-organization flows: a top arch is segmented by region with country ticks along the arc, and curves stream down from each tick into organization nodes sized by total volume. Built for global trade, aid or migration narratives, with dark mode and PNG / SVG export.
Two-Tone Ring Chord Diagram Generator - Bipartite Flow Chart
A two-tone ring chord diagram for bipartite source-to-target flows: a slate top half-ring holds sources and a pink bottom half-ring holds targets, each node an arc sector weighted by its total flow; bezier curves cross the open center toward arrowheads on the target side. Built for threat modeling, capability mapping and requirements traceability; dark mode and PNG / SVG export.
Double Fan Colorful Chord Diagram Generator
A double-fan colorful chord diagram turns bipartite flows into an hourglass: five solid-colored arcs fan across the top and five pastel arcs fan across the bottom along one circle, with open gaps at 3 and 9 o’clock. Translucent colored ribbons cross the center waist, and every sector carries its own tick axis starting at 0 with majors every 10 units. Built for channel flows, cost allocation and requirement coverage; dark mode and PNG / SVG export.
Circos Collinearity Chord Diagram
A Circos collinearity chord diagram treats ring segments as continuous coordinate tracks instead of discrete nodes: outer ticks show positions and thin curves in the center map one interval to another. Built for genome synteny, block migration, address-range remapping, batch reassignment and stratigraphic comparison, with light/dark mode and PNG / SVG export.
Group Flow Chord Diagram Generator
Draws “many sources into a few groups” as one ring: the left half holds small source arcs in a single purple, the right half holds group arcs one colour each with a matching vertical legend, arc width equals node totals, and ribbons are tinted by their target group. White dividers inside group arcs show at a glance how many sources feed each one. Built for sample classification, channel attribution, topic assignment and batch destinations, with dark mode and PNG / SVG export.
Spectral Ring Chord Diagram Generator
Turns a pairwise relationship matrix into a spectral ring: nodes run clockwise from the largest total to the smallest, arc colors are sampled along one continuous ramp so hue is the ranking itself (reddest biggest, bluest smallest), every relationship is a uniform thin teal line bending toward the centre, and white dividers inside an arc are that node’s connection list. Dark mode and PNG / SVG export included.
Arc Diagram Generator
A classic arc diagram that flattens co-occurrence onto one baseline: colored group ticks sit on the line, vertical group-colored labels stand at the left, and relationship strength is drawn as semi-transparent semicircle arcs whose height and thickness vary with the weight — clean even at 400 relations. Great for timelines and ranked pairings; dark mode and PNG / SVG export.
Grouped-Color Rose Chart Generator
Turn category, value and group columns into a Nightingale rose where every petal takes the color of its group, hues flowing smoothly from one segment to the next. Includes a label toggle, light / dark canvas styles and PNG / SVG export, all rendered locally.
Excalidraw Whiteboard
Use a hand-drawn online whiteboard for flowcharts, sketches, wireframes, and annotations with local editing and export.