How to Convert Milliamps to Amps (mA to A): Step-by-Step
Need to convert milliamps to amps but not sure how it works? You’re in the right place. Whether you’re checking your phone charger, working with electronics, or sizing up a power supply, knowing how to switch between milliamps (mA) and amps (A) is super useful. This guide breaks it down simply so you can get what you need—fast.
What Is a Milliampere?
A milliampere, or mA for short, is a unit used to measure small amounts of electric current. It’s equal to one-thousandth of an ampere, so 1,000 milliamps make up just 1 amp.
The prefix “milli-” in the metric system always denotes 10⁻³, so you’ll sometimes see small currents written in scientific form as 1 × 10⁻³ A.
You’ll bump into milliamps whenever you deal with low-power electronics. A smartphone charger, for instance, might deliver 500 mA, while an Arduino microcontroller may draw as little as 20 mA on standby.
Using milliamps keeps the numbers neat. 0.02 A looks abstract, but 20 mA is instantly readable.
What Is an Ampere?
An ampere, usually shortened to amp and written as A, is the standard unit used to measure electric current. It’s a base unit in the International System of Units (SI), meaning it’s one of the core measurements we use in science and engineering.
In 2019, the ampere got a more precise definition. Now, it’s based on something called elementary charge—the charge of a single electron. Technically, 1 amp equals the flow of about 6.241 × 10¹⁸ electrons per second.
If that sounds a bit abstract, don’t worry—it’s more intuitive when you see it in action. For example:
A standard kettle or hair dryer might draw around 10 to 15 A.
A home circuit breaker is usually rated at 10 or 20 A to stop wires from overheating.
A lightning strike? That can hit over 100,000 A for a heartbeat.
Because the ampere is a base unit, other electrical units build on it. Volts, ohms, and watts all reference current in their formulas.
How to Convert Milliamps to Amps
Converting mA into ampere is super simple—you just divide by 1,000. That’s because 1 mA = 0.001 A. So, when you’re dealing with small electrical currents and want to express them in amps, a quick division does the trick.
mA to A Formula:
Amps (A) = Milliamps (mA) ÷ 1000
Example:
Let’s say a device draws 750 mA of current.
To convert that to amps: 750 mA ÷ 1,000 = 0.75 A
So, your device uses 0.75 amps.
This conversion is handy when you’re checking power supplies, figuring out load limits, or comparing specs for devices that switch between units. For example, a power bank rated at 3000 mA delivers 3 A of current.
And if you’re working with battery capacity, it’s also important to understand how to convert milliamp hours to amp hours. The concept is the same: divide by 1000. So, a 5000 mAh battery equals 5 Ah.
How to Convert Amps to Milliamps
Need to go the other way? No problem—just multiply by 1,000. Since 1 A = 1,000 mA, this is a quick way to get more precise when working with smaller devices or low-power circuits.
Formula:
Milliamps (mA) = Amps (A) × 1000
Example:
Suppose your charger says it outputs 2.4 A.
To convert that to milliamps: 2.4 × 1,000 = 2,400 mA
So, the charger delivers 2,400 milliamps of current.
This is especially useful when you’re comparing specs between devices or trying to figure out if a cable or adapter is up to the job. Knowing the number in mA gives you a better feel for what’s happening under the hood.
Milliampere to Ampere Conversion Chart
Just want the number? Below is a chart to give you a quick reference—no calculator required.
Milliamps | Amps |
1 mA | 0.001 A |
10 mA | 0.01 A |
100 mA | 0.1 A |
250 mA | 0.25 A |
500 mA | 0.5 A |
750 mA | 0.75 A |
1,000 mA | 1 A |
2,000 mA | 2 A |
5,000 mA | 5 A |
Why You Might Need to Convert Milliamps to Amps?
So, why bother converting milliamps to amps (or the other way around)? This simple conversion can help you make better decisions when using, buying, or setting up electronic gear. Here are some everyday scenarios where it comes in handy:
Matching Devices with Chargers or USB Ports
Not all chargers or ports are created equal. For example:
A standard USB 2.0 port gives you 500 mA (0.5 A), while USB 3.0 can offer up to 900 mA (0.9 A).
Many phone chargers now push out between 1 A and 2.4 A.
Laptops step things up again: USB-C chargers and now many high-output power banks typically deliver about 3 A to 5 A.
If your device needs more current than the port or charger can supply, it might charge slowly—or not at all. Being able to convert between milliamps and amps helps you make sure everything’s compatible.
Take the EcoFlow Silver RAPID Magnetic Power Bank (10,000 mAh) as an example. It comes with a built-in USB-C cable that can push a full 65W (20 V × 3.25 A) of power, enough for a 13-inch MacBook Air or other slim laptops.
At the same time, it offers Qi2-certified 15W wireless charging for iPhones, so you can just snap it onto the back of your device and go. Whether you’re topping up your phone or charging your laptop at full speed, you won’t need to carry extra cables.
A strong N52 magnetic ring keeps your phone securely attached, while a fold-out kickstand lets you prop it up in portrait or landscape. You can even personalize boot-screen graphics and monitor charging through the EcoFlow app. And when it’s time to recharge, the 65W input gets the power bank itself from 0 to 70% in under 33 minutes.
Understanding Battery Capacity and Run-Time
Batteries are usually rated in milliamp-hours (mAh), but your device might list its current draw in amps (A). Converting between the two helps you estimate how long a battery will last or how big of one you’ll need for a project.
Since 1,000 mAh equals 1 amp-hour (Ah), you can just divide by 1,000 to convert milliamp hours to amp hours. Once you’ve got that, calculating how long your battery will last is easy:
Run-time (hours) = Battery capacity (Ah) ÷ Device draw (A)
For example, say your RC car has a 2,000 mAh battery (that’s 2 Ah), and the motor draws about 1 amp while running.
Just plug it into the formula: 2 Ah ÷ 1 A = 2 hours of run-time (in ideal conditions).
Of course, real-world use—like high-speed bursts or tough terrain—can make the battery drain faster, but this gives you a solid starting point.
Sizing Fuses and Circuit Protection
Fuses and circuit breakers are always rated in amps, but you’ll often see device specs listed in milliamps. If you skip the conversion, you could end up with a fuse that blows too easily—or worse, one that doesn’t blow when it should.
Working with Solar or Off-Grid Systems
If you’re setting up solar panels, portable power stations, or inverters, everything is usually rated in amps. But device specs might be in milliamps, especially for smaller appliances or monitoring gear. Getting the conversion right helps ensure your system is properly balanced and won’t overload.
Building or Troubleshooting Electronics
Electronics projects often involve components that draw very small currents:
An Arduino board might only draw 20 mA when idle.
LED strips might use 60 mA per segment or over 1 A per metre at full brightness.
Knowing how to switch between units makes it easier to figure out your total power draw and avoid flickering, overheating, or unstable circuits.
Using a Multimeter Safely
Multimeters have different ports and fuses for measuring milliamps versus amps. Knowing your expected current before you start measuring helps you plug into the right port and avoid blowing a fuse in your tool.
Conclusion
That’s all there is to it. Converting milliamps to amps is just a matter of moving the decimal. It’s the kind of thing that comes in handy more often than you’d think, whether you’re sizing up power banks, working on a DIY project, or just making sure your devices are powered safely. With the basics sorted, you’ll be able to spot the right info, do the maths in seconds, and avoid mismatched gear down the track.
FAQs
Is 1000 milliamps equal to 1 amp?
Yes. 1000 milliamps (mA) is exactly equal to 1 amp (A). This is because “milli” is a metric prefix meaning one-thousandth. So, when you multiply 1000 mA by 0.001, you get 1 A. This conversion is a basic but important concept when working with different types of electrical devices.
How to convert mA to amps?
To convert milliamps (mA) to amps (A), simply divide the number of milliamps by 1,000, since 1 amp is equal to 1,000 milliamps. For example, 250 mA is 0.25 A. Just remember: move the decimal three places to the left!
What is 30 mA in amps?
To convert 30 milliamps to amps, use the formula: 30 mA ÷ 1000 = 0.03 A. So, 30mA equals 0.03 amps. This amount of current is typical for small sensors or electronic components with low power requirements.
Is 500 milliamps the same as 5 amps?
No, 500 milliamps is not the same as 5 amps. 500 mA ÷ 1000 = 0.5 A, which is only half an amp. In contrast, 5 amps equals 5000 mA. Always double-check your conversion by dividing the milliamps by 1,000.