How Loadster Fuel works
Loadster Fuel is the pay-as-you-go currency for load testing and monitoring. Bots burn it while they run, so you pay for the tests you actually run, not for seats or idle time. Every new account starts with 50 units, no credit card required.
Loadster Fuel prices
Buy fuel when you need it. There's no subscription, and fuel you buy never expires. Bigger packs cost less per unit.
1,000 units
About $0.097 per unit
Enough for 1,000 Protocol Bot-hours, or 250 Browser Bot-hours
Buy 1K fuel
5,000 units
About $0.079 per unit
Enough for 5,000 Protocol Bot-hours, or 1,250 Browser Bot-hours
Buy 5K fuel
10,000 units
About $0.070 per unit
Enough for 10,000 Protocol Bot-hours, or 2,500 Browser Bot-hours
Buy 10K fuel
20,000 units
About $0.050 per unit
Enough for 20,000 Protocol Bot-hours, or 5,000 Browser Bot-hours
Buy 20K fuel
Bulk fuel
Volume pricing
Need more than 20,000 units, or a year's worth up front? We'll quote a volume price.
Get a quoteThe Loadster Fuel formula and calculator
Only load tests and monitor cycles burn fuel. Editing scripts, designing scenarios, and reading reports are free, however many teammates do them.
Fuel Calculator
fuel ≈ duration × bots × rate
Duration × bots × rate
Loadster Fuel vs. VU-hours
One unit of fuel is one Protocol Bot running for one hour, the same idea as a VU-hour (virtual user hour). Browser Bots and Playwright scripts use 4 units per bot-hour.
Unlike tools that round every test up to the next hour or charge a minimum per test, Loadster calculates fuel to the second. A 7-minute test with 100 Protocol Bots burns about 11.7 units, not 100. More about Loadster Fuel and VU-hours
The calculator gives a flat estimate. Load tests ramp up and down, and fuel counts the whole test at its peak bot count, so real tests can burn a little more. On the Team plan you don't have to do this math at all.
Loadster Fuel examples for load tests and monitors
Load tests and monitors use the same formula. A monitor is like a one-bot test that lasts as long as its script, so most monitors burn a few units a day.
Load tests
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100 Protocol Bots for 6 minutes
0.1 h × 100 × 1 = 10 units
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250 Browser Bots for 6 minutes
0.1 h × 250 × 4 = 100 units
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1,000 Protocol Bots for 15 minutes
0.25 h × 1,000 × 1 = 250 units
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500 Browser Bots for 15 minutes
0.25 h × 500 × 4 = 500 units
Monitors, per day
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Browser Bot, 45-second script every hour (18 minutes a day)
0.3 h × 1 × 4 = 1.2 units
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Browser Bot, 20-second script every 10 minutes (48 minutes a day)
0.8 h × 1 × 4 = 3.2 units
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Protocol Bot, 30-second script every 5 minutes (2.4 hours a day)
2.4 h × 1 × 1 = 2.4 units
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Protocol Bot, 4-second script every minute (96 minutes a day)
1.6 h × 1 × 1 = 1.6 units
If you run lots of monitors, or run them often, a monitoring plan covers them without burning fuel. The Team plan includes monitoring too.
Loadster Fuel FAQs
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Why do Browser Bots and Playwright scripts burn more fuel?
Each one drives a real Chrome browser, which takes more cloud compute than Protocol Bots sending HTTP requests. The 4× multiplier tracks that infrastructure cost. Protocol Bots are the economical choice for APIs and high-volume HTTP; real browsers are for JavaScript, page resources, and front-end timing.
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How do the 50 free units of fuel work?
Every new account starts with 50 units. That's enough for a handful of short tests, such as five 6-minute tests with 100 Protocol Bots each. No credit card required. The 50 units are a starter amount, not a monthly refill. When they run out you can buy more fuel or switch to the Team plan; your scripts and reports stay put.
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Does unused Loadster Fuel expire?
No. Fuel you buy stays in your account until you use it, whether that's next week or next year.
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Do you offer bulk fuel pricing?
Yes. If you need more than 20,000 units, or want to buy a year's worth of fuel up front, email sales@loadster.com and we'll put together a quote.
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Is Loadster Fuel the same as VU-hours?
Close. One unit of fuel is one Protocol Bot running for one hour, the same idea as a VU-hour (virtual user hour). Browser Bots and Playwright scripts use 4 units per bot-hour. There's more detail in what is Loadster Fuel.
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What happens if we run out of fuel during a test?
Loadster checks your balance before a test starts and won't launch one that your fuel can't cover. If you run low, add fuel from the Billing page. Your scripts, scenarios, and reports stay put either way.
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Do we have to use fuel at all?
No. The Loadster Team plan includes load testing and monitoring for one flat price, so you don't have to watch a fuel balance. You can still run an occasional oversized test with fuel.