Calendar Heatmap Generator: Free Contribution Graph
Making a calendar heatmap image is quick: open the free generator, enter your date and value pairs, pick a color ramp, and download a PNG or SVG. It's the fastest way to turn a year of daily numbers into a GitHub-style grid that shows streaks and gaps at a glance.
What a calendar heatmap showsWhat a calendar heatmap shows
A calendar heatmap draws one small cell per day, laid out in a grid of weeks. Each cell is colored by that day's value: light for a quiet day, dark for a busy one. Line up a full year and you get a wall of color that reads like a habit tracker. GitHub made the pattern famous with its green contribution graph, but the same grid fits any daily number.
You reach for one when you're tracking something that happens day after day and you want the rhythm to show:
- Streaks and habits: posting cadence, workouts logged, days you shipped code.
- Daily metrics: sales per day, signups, active users, tickets closed.
- Usage patterns: API calls, page views, or any count that ebbs and flows through the week.
A table can hold the same values, but the grid makes the shape obvious. A long dark run is a streak. A pale patch is a slump. The eye finds those instantly, which is why contribution graphs end up on profiles, dashboards, and yearly recaps.
Make one freeMake one free
Open the calendar heatmap maker. You enter your date and value pairs, and the tool places a cell for each day and shades it. Pick a color ramp that fits your brand or mood, tweak the range, and watch the grid fill in as you go.
There's no account to create and nothing to install. When the heatmap looks right, you download it. You get a clean PNG for READMEs and slides, or an SVG if you want it sharp at any size. No signup, no watermark, no credit card.
That covers the one-off case. If your data changes daily or you need one heatmap per user, keep reading.
Embed it anywhereEmbed it anywhere
A heatmap from the tool is just an image, which is what makes it easy to place. Drop it into a README, a profile page, or a weekly email. In markdown or HTML, one line does it:
A static file is perfect for a fixed recap. But a contribution graph is meant to move. Embed a render URL instead of a saved file and the image regenerates on each load, so today's activity shows up without you touching anything. Push a new value and the streak in your README grows on its own. Same one-line embed, live data behind it.
Generate at scaleGenerate at scale
When you need more than one heatmap, the API takes over. A single render call turns your date and value pairs into a finished image, and you swap the data per request. One design covers every user profile, every dashboard tile, or every automated digest email.
Here are the paths, from least to most hands-off:
- API: the API docs walk through a render call with tested examples you can copy and run.
- Component: the calendar heatmap is a first-class API component, so you set the days, values, and color ramp as fields. See the calendar component for what you can configure.
- AI agent: an AI agent can build the heatmap over MCP, so you describe the data in plain language and it produces the image.
Pick the level that fits. A quick script wants the API, a repeatable design wants the component, and a hands-off workflow hands it to an agent.
Start with the calendar heatmap makerStart with the calendar heatmap maker
For a single graph, the calendar heatmap maker gets you a PNG or SVG in a minute, free and unwatermarked. To automate it, read the calendar component reference, then wire it up through the API docs or hand it to an AI agent.
The free plan includes 100 renders a month, which is plenty to test the automated path before you scale it up. Build the contribution graph that keeps your streak on display.