End-of-Test Summary

Understand the end-of-test summary that k6 displays after your test completes, including metrics, thresholds, and checks.

End-of-Test Summary

When a test finishes, k6 prints a summary of aggregated results to stdout. This summary provides a comprehensive overview of your test execution, organized by thresholds, checks, and metric categories.

Summary Modes

k6 provides three display modes through the --summary-mode option:

compact (default)

The compact mode displays the most relevant test results in a concise format, focusing on:

• Threshold results
• Check results
• Aggregated metrics by category

k6 run script.js
# or explicitly
k6 run --summary-mode=compact script.js

Example output:

  █ THRESHOLDS

    http_req_duration
    ✓ 'p(95)<1500' p(95)=148.21ms
    ✓ 'p(90)<2000' p(90)=146.88ms

    http_req_failed
    ✓ 'rate<0.01' rate=0.00%


  █ TOTAL RESULTS

    checks_total.......................: 90      13.122179/s
    checks_succeeded...................: 100.00% 90 out of 90
    checks_failed......................: 0.00%   0 out of 90

    ✓ test-api.k6.io is up
    ✓ status is 200

    CUSTOM
    custom_waiting_time................: avg=152.355556 min=120      med=141      max=684      p(90)=147.2    p(95)=148.8

    HTTP
    http_req_duration..................: avg=140.36ms   min=119.08ms med=140.96ms max=154.63ms p(90)=146.88ms p(95)=148.21ms
      { expected_response:true }.......: avg=140.36ms   min=119.08ms med=140.96ms max=154.63ms p(90)=146.88ms p(95)=148.21ms
    http_req_failed....................: 0.00%  0 out of 45
    http_reqs..........................: 45     6.56109/s

    EXECUTION
    iteration_duration.................: avg=152.38ms   min=119.37ms med=141.27ms max=684.62ms p(90)=147.11ms p(95)=148.39ms
    iterations.........................: 45     6.56109/s
    vus................................: 1      min=1       max=1
    vus_max............................: 1      min=1       max=1

    NETWORK
    data_received......................: 519 kB 76 kB/s
    data_sent..........................: 4.9 kB 718 B/s

full

The full mode includes everything from compact mode plus:

• All HTTP timing metrics (blocked, connecting, TLS handshaking, sending, waiting, receiving)
• Group-specific results
• Scenario-specific results

k6 run --summary-mode=full script.js

This mode is useful when you need detailed breakdowns by scenario or group, or when you want to see all HTTP timing phases.

legacy

The legacy mode uses the pre-v1.0.0 summary format for backward compatibility.

k6 run --summary-mode=legacy script.js

Use this mode if you have tooling that depends on the old format.

Understanding the Summary

Thresholds Section

Thresholds appear at the top of the summary with clear pass/fail indicators:

• ✓ Indicates a passing threshold
• ✗ Indicates a failing threshold

Each threshold shows its expression and the actual value:

http_req_duration
✓ 'p(95)<1500' p(95)=148.21ms
✗ 'p(99)<500' p(99)=687.43ms

If any threshold fails, k6 exits with a non-zero status code, making it perfect for CI/CD pipelines.

Checks Section

Checks show pass/fail ratios for assertions in your test:

checks_total.......................: 90      13.122179/s
checks_succeeded...................: 100.00% 90 out of 90
checks_failed......................: 0.00%   0 out of 90

✓ test-api.k6.io is up
✓ status is 200

Unlike thresholds, failed checks do not cause k6 to exit with an error. They’re for informational purposes.

Metrics by Category

Metrics are organized into categories based on their source:

CUSTOM - Your custom metrics using Trend, Counter, Gauge, or Rate

HTTP - Metrics from the k6/http module:

• http_req_duration - Total request time
• http_req_blocked - Time waiting for a free connection slot
• http_req_connecting - Time establishing TCP connection
• http_req_tls_handshaking - Time performing TLS handshake
• http_req_sending - Time sending request data
• http_req_waiting - Time waiting for server response (TTFB)
• http_req_receiving - Time receiving response data
• http_req_failed - Rate of failed requests
• http_reqs - Total number of requests

EXECUTION - Test execution metrics:

• iteration_duration - Time to complete one full iteration
• iterations - Total number of iterations completed
• vus - Current number of active virtual users
• vus_max - Maximum VUs allocated

NETWORK - Data transfer metrics:

• data_received - Total data received
• data_sent - Total data sent

Categories only appear when relevant. For example, browser metrics appear only when using k6/browser.

Customization Options

k6 provides several options to customize the summary output:

CLI Flags

# Choose summary mode
k6 run --summary-mode=full script.js

# Disable summary
k6 run --no-summary script.js

# Select trend statistics
k6 run --summary-trend-stats="min,avg,max,p(95),p(99)" script.js

# Set time unit
k6 run --summary-time-unit=ms script.js

Available Options

Option	Description	Default
--summary-mode	Display mode: compact, full, or legacy	compact
--no-summary	Disable end-of-test summary	false
--summary-trend-stats	Statistics to show for Trend metrics	avg,min,med,max,p(90),p(95)
--summary-time-unit	Time unit for all values (s, ms, us)	Auto-detected

Custom Summary with handleSummary()

For complete control over the summary output, use the handleSummary() function in your test script:

import http from 'k6/http';
import { textSummary } from 'https://jslib.k6.io/k6-summary/0.0.2/index.js';

export const options = {
  vus: 10,
  duration: '30s',
  thresholds: {
    http_req_duration: ['p(95)<500'],
  },
};

export default function () {
  http.get('https://test.k6.io');
}

export function handleSummary(data) {
  return {
    'stdout': textSummary(data, { indent: ' ', enableColors: true }),
    'summary.json': JSON.stringify(data),
    'summary.html': htmlReport(data),
  };
}

function htmlReport(data) {
  const passed = data.metrics.http_req_duration.thresholds['p(95)<500'].ok;
  return `
    <!DOCTYPE html>
    <html>
      <head><title>k6 Test Report</title></head>
      <body>
        <h1>Test Results: ${passed ? 'PASSED' : 'FAILED'}</h1>
        <p>Duration: ${data.state.testRunDurationMs}ms</p>
        <p>Requests: ${data.metrics.http_reqs.values.count}</p>
        <p>P95: ${data.metrics.http_req_duration.values['p(95)']}ms</p>
      </body>
    </html>
  `;
}

The handleSummary() function:

• Receives the complete metrics data object
• Returns a map of {destination: content} pairs
• Can output to stdout, stderr, or any file path
• Allows multiple outputs simultaneously

For more details on custom summaries, see the Custom Summary documentation.

CI/CD Integration

The end-of-test summary is ideal for CI/CD pipelines:

GitHub Actions

name: Load Test
on: [push]
jobs:
  k6:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Run k6 test
        uses: grafana/k6-action@v0.3.1
        with:
          filename: test.js
      # k6 exits with code 99 if thresholds fail

Next Steps

Custom Summary

Create fully customized summary reports with handleSummary()

Real-Time Output

Stream metrics during test execution for live monitoring

Thresholds

Learn how to define performance requirements with thresholds

Checks

Understand how to add assertions to your tests