Betaflight Rates Calculator

Tuning Inputs

Rate and Expo Variable Definitions

Variable	Meaning	Unit	Typical Range
Rate	Maximum rotation speed around an axis.	Degrees per Second (dps) or Revolutions per Second (rps)	50 – 300 dps
Expo	Exponent applied to stick input to modify sensitivity near the center.	Unitless	-1.0 to 1.0
Stick Input	Raw input from your transmitter stick (normalized 0 to 1).	Unitless	-1.0 to 1.0
Output Rate	Actual rotation speed applied by the flight controller.	Degrees per Second (dps) or Revolutions per Second (rps)	Varies based on Rate and Stick Input

What is a Betaflight Rates Calculator?

{primary_keyword} are fundamental parameters in FPV drone flight control software like Betaflight. They dictate how quickly your drone rotates around its Pitch, Roll, and Yaw axes when you move the control sticks on your transmitter.

A Betaflight Rates Calculator is a tool designed to help FPV pilots fine-tune these crucial settings. It allows you to input your desired 'Rates' (maximum rotation speed) and 'Expo' (stick response curve) and see how they translate into actual flight behavior. This helps pilots achieve a more predictable, responsive, and comfortable flying experience, whether they are freestyling, racing, or performing cinematic maneuvers.

Who should use it?

• New FPV pilots trying to find comfortable stick feel.
• Experienced pilots experimenting with new tuning styles.
• Pilots who want to understand the relationship between stick input and drone response.
• Anyone looking to optimize their drone's agility and precision.

Common Misunderstandings:

• Confusing Rates and PID: Rates control the *maximum* rotation speed, while PID controllers manage how the drone *achieves and maintains* that rotation. They are separate but work together.
• Unit Confusion: Rates can be set in Degrees per Second (dps) or Revolutions per Second (rps). It's crucial to understand which unit your flight controller firmware is expecting and to be consistent. Our calculator supports both.
• Expo Misinterpretation: Expo doesn't directly change the maximum rate; it changes the *sensitivity* of the stick near the center. Negative expo makes the center less sensitive (smoother for fine control), while positive expo makes it more sensitive (quicker initial response).

Betaflight Rates and Expo Formula and Explanation

The core of rate calculation involves understanding how your stick input is translated into a command for the flight controller, modified by both the 'Rate' and 'Expo' settings. Betaflight uses a specific formula to calculate the output rate based on stick input and the configured rates and expo for each axis (Pitch, Roll, Yaw).

The General Formula (Conceptual)

While Betaflight's internal implementation is complex, the effective output rate can be conceptually understood as:

Output Rate = (Input_Function(Stick_Input, Expo)) * Rate

Where:

• Stick Input: The raw value from your transmitter stick, typically normalized from -1.0 (full deflection one way) to +1.0 (full deflection the other way), with 0 being the center.
• Expo: A value that modifies the stick input curve. Higher positive values flatten the curve near the center, making it less sensitive. Higher negative values steepen the curve near the center, making it more sensitive.
• Input_Function(Stick_Input, Expo): This is the non-linear transformation applied to the stick input based on the expo value. Betaflight uses a polynomial function for this.
• Rate: Your configured maximum rotation speed in Degrees per Second (dps) or Revolutions per Second (rps). This scales the output of the input function to your desired maximum speed.

Simplified Calculation for Midpoint Sensitivity

A common way to understand expo's effect is by looking at the sensitivity at the stick's midpoint (e.g., 50% stick deflection). A simplified view of the input function's output at 50% stick input might look like:

Input_Function_Output_at_50% = sign(Stick_Input) * pow(abs(Stick_Input), 1 / (1 + Expo))

Then, the effective rate at that point is:

Effective Rate at 50% = Rate * pow(0.5, 1 / (1 + Expo))

This calculation is what our calculator uses to approximate "Midpoint Sensitivity". A value closer to 1.0 means the stick is highly sensitive near the center, while a value closer to 0.0 means it's less sensitive.

Variables Table

Variables Used in Rate Calculation

Variable	Meaning	Unit	Typical Range
Pitch Rate	Desired maximum pitch rotation speed.	dps / rps	50 – 300 dps
Roll Rate	Desired maximum roll rotation speed.	dps / rps	50 – 300 dps
Yaw Rate	Desired maximum yaw rotation speed.	dps / rps	80 – 400 dps
Pitch Expo	Expo value for pitch axis.	Unitless	-1.0 to 1.0
Roll Expo	Expo value for roll axis.	Unitless	-1.0 to 1.0
Yaw Expo	Expo value for yaw axis.	Unitless	-1.0 to 1.0
Stick Mode	Transmitter stick configuration.	Mode Number	1, 2, 3, 4
Rate Units	Selected unit for rates.	'dps' or 'rps'	N/A

Practical Examples

Let's see how the Betaflight Rates Calculator helps in real-world scenarios.

Example 1: Finding a Balanced Freestyle Tune

A pilot wants a drone that feels agile but still allows for precise control during complex freestyle maneuvers. They prefer Mode 2 stick mode.

• Inputs:
  • Pitch Rate: 120 dps
  • Roll Rate: 120 dps
  • Yaw Rate: 250 dps
  • Pitch Expo: 0.20
  • Roll Expo: 0.20
  • Yaw Expo: 0.10
  • Stick Mode: Mode 2
  • Rate Units: dps
• Calculator Output:
  • Effective Pitch Rate: 120.00 dps
  • Effective Roll Rate: 120.00 dps
  • Effective Yaw Rate: 250.00 dps
  • Pitch Midpoint Sensitivity: ~0.65
  • Roll Midpoint Sensitivity: ~0.65
  • Yaw Midpoint Sensitivity: ~0.85
  • Primary Result: Balanced Agility

Interpretation: The pilot achieves their desired maximum rotation speeds. The higher expo on pitch and roll (0.20) results in lower midpoint sensitivity (~0.65), meaning the sticks are less twitchy right at the center, aiding control. The lower yaw expo (0.10) keeps yaw responses relatively quicker.

Example 2: Transitioning from dps to rps

A pilot is used to thinking in terms of full rotations and wants to set up a new drone using Revolutions per Second (rps) for rates.

• Inputs:
  • Pitch Rate: 5.0 rps
  • Roll Rate: 5.0 rps
  • Yaw Rate: 8.0 rps
  • Pitch Expo: 0.15
  • Roll Expo: 0.15
  • Yaw Expo: 0.05
  • Stick Mode: Mode 2
  • Rate Units: rps
• Calculator Output:
  • Effective Pitch Rate: 5.00 rps
  • Effective Roll Rate: 5.00 rps
  • Effective Yaw Rate: 8.00 rps
  • Pitch Midpoint Sensitivity: ~0.73
  • Roll Midpoint Sensitivity: ~0.73
  • Yaw Midpoint Sensitivity: ~0.93
  • Primary Result: Responsive Control

Interpretation: The calculator confirms the rates in the chosen unit (rps). The sensitivity values indicate a fairly responsive stick feel across all axes, with yaw being slightly more immediate due to lower expo. If the pilot wanted to convert these to dps, they would multiply the rps values by 360 (1 rotation = 360 degrees).

How to Use This Betaflight Rates Calculator

Using the Betaflight Rates Calculator is straightforward. Follow these steps to dial in your drone's flight characteristics:

1. Select Your Stick Mode: Ensure the 'Stick Mode' dropdown matches how your transmitter is configured (Mode 2 is the most common, with throttle on the left stick).
2. Set Desired Rates: Input the maximum rotation speed you want for Pitch, Roll, and Yaw into the respective 'Rate' fields. Think about the type of flying you do. Faster rates are good for aggressive maneuvers, while slower rates can be better for stability and precision.
3. Adjust Expo: Enter your desired 'Expo' values. Start with defaults like 0.15-0.20 for Pitch/Roll and 0.05-0.10 for Yaw. Lower values (closer to 0) make the sticks less sensitive near the center, which can help with fine control. Higher values (closer to 1) make the center more sensitive. Negative values are less common but can be used for specific tuning goals.
4. Choose Your Units: Select whether you prefer to work with 'Degrees per Second (dps)' or 'Revolutions per Second (rps)' for your rates. This ensures the calculator uses the correct conversion if needed and helps you match your Betaflight Configurator settings.
5. Click 'Calculate Rates': The calculator will instantly display the effective rates (which should match your input unless units were converted) and the calculated midpoint sensitivity for each axis.
6. Interpret Results:
   • Effective Rates: These are your target maximum rotation speeds.
   • Midpoint Sensitivity: A value closer to 1.0 indicates high sensitivity around the center stick position. A value closer to 0.0 indicates low sensitivity (smoother, less twitchy).
   • Primary Result: Provides a general classification of the overall stick response based on your inputs.
7. Copy Settings: Use the 'Copy Results' button to copy the calculated values and units to your clipboard for easy pasting into your Betaflight Configurator.
8. Reset: If you want to start over or return to the default settings, click the 'Reset Defaults' button.

Remember to test these settings in a simulator or a safe, open area before flying aggressively. Fine-tuning rates is often an iterative process.

Key Factors That Affect Betaflight Rates

Several factors influence how your chosen rates and expo translate into actual flight performance. Understanding these helps in effective tuning:

1. Your Flying Style: Aggressive freestyle requires higher rates and potentially less expo for quick flips and rolls. Cinematic or stable flight might benefit from lower rates and more expo for smoother control.
2. Drone Size and Weight: Larger, heavier drones generally need lower rates to avoid becoming unstable or difficult to control. Smaller, lighter drones can often handle much higher rates.
3. Motor KV and Propeller Choice: Higher KV motors and larger props provide more thrust and torque, allowing the drone to reach higher rotation speeds (effectively increasing the 'Rate' capability). Lower KV motors with smaller props might struggle to achieve very high rates.
4. PID Loop Frequency and Filters: The underlying PID controller and filtering settings significantly impact how well the drone can follow your rate commands. Aggressive PIDs or insufficient filtering can cause oscillations, making high rates feel uncontrollable. Conversely, overly smooth PIDs might make the drone feel sluggish even with high rates. Check out our Betaflight PID Controller Guide.
5. Transmitter and Receiver Latency: Higher latency introduces delays between your stick movement and the drone's reaction, which can make high rates feel less direct or even laggy. Lower latency systems provide a more immediate response.
6. Pilot Skill and Experience: What feels "fast" or "agile" is subjective. As pilots gain experience, they often increase their rates to match their improving reflexes and ability to handle quicker movements.
7. Betaflight Version: Different versions of Betaflight might have subtle changes in how rates and expo are implemented or processed, potentially affecting the feel.

FAQ

• Q: What's the difference between dps and rps for rates?
  A: 'dps' stands for Degrees per Second, measuring how many degrees the drone rotates in one second. 'rps' stands for Revolutions per Second, measuring how many full 360-degree rotations the drone completes in one second. 1 rps is equal to 360 dps. Choose the unit that matches your comfort level and your Betaflight Configurator settings.
• Q: My drone feels twitchy on the sticks. How can I fix it?
  A: Increase the Expo value for the affected axis (Pitch, Roll, or Yaw). This makes the stick less sensitive near the center. You might also consider slightly lowering the Rate for that axis if the overall speed is too high.
• Q: My drone feels too slow and sluggish. What should I do?
  A: Lower the Expo value (closer to 0 or even negative) for the affected axis to make the sticks more sensitive near the center. You can also increase the Rate to allow for faster maximum rotation. Ensure your PID gains are not too low, as this can also cause sluggishness.
• Q: Can I use negative expo?
  A: Yes, negative expo makes the stick *more* sensitive near the center. This is less common for general tuning but can be useful for specific applications where immediate, sharp reactions are needed right off center, though it can make fine control difficult.
• Q: How does stick mode affect rates?
  A: Stick mode determines which physical stick controls which axis (Pitch, Roll, Yaw, Throttle). The rates and expo settings themselves are independent of the stick mode; they define the *behavior* associated with each axis, regardless of which stick controls it.
• Q: Does this calculator account for PID tuning?
  A: No, this calculator focuses specifically on Rates and Expo. PID tuning affects how the drone achieves and maintains the commanded rotation speed. While essential for a good tune, PID values are separate inputs. You can learn more about Tuning PID Controllers.
• Q: What does the 'Effective Rate' mean?
  A: The 'Effective Rate' usually matches your input 'Rate' when using 'dps' or 'rps' as the unit. It represents the maximum rotational speed your drone *can* achieve around that axis based on your configured Rate. The actual speed will vary based on stick input and the expo curve.
• Q: The chart shows a curve, but my sticks are linear. Why?
  A: The chart visualizes how the 'Expo' setting non-linearly modifies your linear stick input. The flight controller interprets this modified input to generate the final output rate. The curve represents the translation from your physical stick movement to the drone's command.

Related Tools and Internal Resources

To further enhance your FPV drone tuning knowledge, explore these related resources:

• FPV Drone PID Tuning Guide: A comprehensive walkthrough of PID controller tuning in Betaflight.
• Understanding Betaflight Filtering: Learn how filters affect flight characteristics and how to adjust them.
• Choosing the Right Propellers for FPV Drones: How prop choice impacts performance, efficiency, and the need for rate adjustments.
• RC Transmitter Basics for FPV Pilots: Essential information about your radio transmitter, including stick modes and setup.