Climb Gradient Calculator for IFR | Aviator.NYC

When you depart IFR, you need to be assured that you will clear all the obstacles in your takeoff path. This guide teaches you the math behind climb gradients, where to find them, and how to convert feet-per-nautical-mile into something your VSI actually shows—feet-per-minute. Use the interactive tools below to practice and build intuition.

Quick Reference

Climb Gradient Formulas & Common Values
What You Need	Formula / Value
Standard IFR gradient	200 ft/NM
Convert to ft/min	`FPM = (Groundspeed × ft/NM) ÷ 60`
Reverse calculation	`ft/NM = (FPM × 60) ÷ Groundspeed`
Mental math trick	ft/NM value = required FPM at 60 kt GS

Common Examples (200 ft/NM Standard Gradient)

Groundspeed	Required Climb Rate
90 kt	300 fpm
120 kt	400 fpm
140 kt	467 fpm
160 kt	533 fpm

⚠️Training Tools Only

The calculators and tools on this page are for educational purposes—practice the math and build intuition. Always verify performance data from your aircraft's POH and current conditions before any real flight.

The Standard IFR Climb Gradient (200 ft/NM)

A climb gradient is the ratio between distance traveled and altitude gained. It's expressed in feet per nautical mile (ft/NM)—not feet per minute. The standard IFR climb gradient is 200 ft/NM, which provides obstacle clearance for most departures.

Here's what that means: for every nautical mile you travel horizontally, you need to gain at least 200 feet of altitude. This creates a 40:1 obstacle clearance surface that procedure designers use to ensure you'll clear terrain and obstructions.

Diverse Departure Criteria

When an airport has been evaluated and found to have no obstacles within the 200 ft/NM climb surface up to the minimum IFR altitude, it meets "diverse departure" criteria. This means:

No departure procedure (DP) needs to be published
After reaching 400 ft AGL on runway heading, you can safely turn in any direction
You're expected to climb at least 200 ft/NM until reaching your assigned altitude

If the airport doesn't meet diverse departure criteria—meaning obstacles penetrate that 40:1 surface—the FAA publishes an Obstacle Departure Procedure (ODP) with specific routing or a steeper climb gradient requirement.

Where to Find Required Climb Gradients

Climb gradients "greater than standard" are called out runway-by-runway in published procedures. Here's where to look:

Finding Climb Gradients on Charts video thumbnail — Where to find non-standard climb gradients in FAA and Jeppesen publications

In the FAA Terminal Procedures Publication, look for the "IFR Takeoff Minimums and (Obstacle) Departure Procedures" section. Airports are listed alphabetically, and each runway with non-standard requirements will specify the required gradient and the altitude at which the standard 200 ft/NM resumes.

Example: KPOU Runway 15

At Poughkeepsie (KPOU), Runway 15 requires a 370 ft/NM climb gradient up to 700 feet, after which the standard 200 ft/NM resumes. This appears both in the textual ODP and on any associated SID. At 90 kt groundspeed, that means you need approximately 555 fpmuntil reaching 700 ft—significantly more than the 300 fpm you'd need for a standard gradient.

Climb Gradient Formula: ft/NM ↔ ft/min

Your VSI shows feet per minute, but climb gradients are published in feet per nautical mile. You need to convert between them.

Converting Climb Gradients video thumbnail — How to convert feet per nautical mile to feet per minute

The Exact Formulas

💡Forward Calculation

Required FPM = (Groundspeed in knots × Required ft/NM) ÷ 60

Example: (90 kt × 370 ft/NM) ÷ 60 = 555 fpm

💡Reverse Calculation

Achievable ft/NM = (Your climb rate in fpm × 60) ÷ Groundspeed

Example: (700 fpm × 60) ÷ 100 kt = 420 ft/NM

The Mental Math Trick

Here's an easier way to think about it: treat the published gradient as if it were the required FPM at 60 knots groundspeed.

At 60 kt GS: required FPM = gradient value (200 ft/NM → 200 fpm)
At 120 kt GS: double it (200 ft/NM → 400 fpm)
At 90 kt GS: multiply by 1.5 (200 ft/NM → 300 fpm)

Common Gotchas

⚠️Watch Out For

Groundspeed vs. Airspeed: A headwind on departure means lower groundspeed, which actually helps—you need less FPM to meet the gradient.
High Density Altitude: This is a double penalty. Your climb rate drops AND your groundspeed increases. Both work against you.
Gradient altitude limit: The non-standard gradient ends at a specific altitude (e.g., "370 ft/NM to 700 ft"). After that, standard 200 ft/NM applies.

Climb Gradient Calculator

Use this interactive calculator to practice converting between ft/NM and ft/min. Toggle between modes to explore how groundspeed affects your required climb rate or achievable gradient.

Training Tool Only: This calculator is for educational purposes—practice the math and build intuition. Always verify performance data from your aircraft's POH and current conditions before any real flight.

Climb Gradient Playground

Required Climb Gradient (ft/NM)

100200 (std)300400600

Groundspeed (knots)

6090120150180

Required Climb Rate

300 ft/min

To meet 200 ft/NM at 90 kt GS

How groundspeed affects your required climb rate:

Groundspeed	Required FPM
70 kt	233 ft/min
80 kt	267 ft/min
90 kt(current)	300 ft/min
100 kt	333 ft/min
110 kt	367 ft/min

Remember:

• Headwind on departure = lower groundspeed = easier gradient
• High density altitude: reduces climb rate AND increases groundspeed (double penalty)
• The gradient requirement ends at a specific altitude—check the procedure!

Formulas:

Required FPM:

FPM = (GS × ft/NM) ÷ 60

Achievable Gradient:

ft/NM = (FPM × 60) ÷ GS

Mental math trick: The ft/NM value equals the required FPM at 60 kt GS. At 120 kt, double it. At 90 kt, multiply by 1.5.

Visual Reference Chart

This chart shows the relationship between groundspeed and required climb rate for common gradients. Plot your own performance to see which gradients you can meet.

Climb Gradient Reference Chart

Standard (200 ft/NM)

300 ft/NM

400 ft/NM

500 ft/NM

How to read this chart: Find your groundspeed on the X-axis, then move up to see what climb rate (Y-axis) you need for each gradient. If your aircraft's climb rate is above a line, you can meet that gradient. Plot your own point to visualize your capability.

Can Your Airplane Actually Make That Gradient?

Knowing the math is one thing—knowing whether your airplane can actually do it is another. Here's a practical workflow:

Check your POH/AFM: Find your aircraft's climb performance at the expected weight and density altitude. Remember, book numbers are best-case scenarios.
Apply a margin: Subtract 10-20% for aging engine, imperfect technique, and the increased workload of instrument flying. If the book says 800 fpm, plan for 650-700.
Convert to gradient: Use the reverse formula to see what gradient you can actually meet at your expected groundspeed.
Compare to requirement: If it's close, consider departing at a lower groundspeed (better gradient capability) or waiting for better conditions.

💡Practical Tip

If your achievable gradient is within 10% of the required gradient, treat it as marginal. Either find an alternative (like a VCOA) or wait for conditions that give you more margin.

Understanding ODPs, SIDs, and Non-Standard Minimums

When Do You Turn After Departure? video thumbnail — Understanding when to turn on diverse departures, ODPs, and SIDs

What ODPs Are

Obstacle Departure Procedures (ODPs) exist when the standard 200 ft/NM surface isn't enough to clear obstacles. They may be:

Textual: Written instructions like "Climb runway heading to 1400 before turning..."
Graphic: Published as a chart with "(OBSTACLE)" in the title

SIDs vs ODPs

Standard Instrument Departures (SIDs) also provide obstacle clearance, but they're primarily ATC tools for traffic flow. Key differences:

SIDs require ATC assignment; ODPs don't
If not assigned a SID or radar vectors, you may still need to fly the ODP for obstacle clearance
When flying an ODP with a defined route, inform ATC before departure

Visual Climb Over Airport (VCOA)

When you can't meet the gradient but have VMC, a VCOA may be available. You climb visually over the airport to a specified altitude, then proceed IFR. This requires:

VMC at the airport
Prior coordination with ATC
Following the specific VCOA procedure for that airport

Non-Standard Takeoff Minimums

For aircraft that can't meet a required gradient, procedures publish alternate ceiling/visibility minimums. These allow visual obstacle avoidance instead of climb gradient compliance:

Ceiling: Usually 100 ft above the controlling obstacle
Visibility: At least 1 SM

⚠️Risk Management

Just because you legally can depart with higher ceiling/visibility instead of meeting the gradient doesn't mean you always should. The gradient exists because there's something out there to hit.

Early Turns

Standard rule: don't turn more than 15° before 400 ft AGL unless directed. However, some DPs require "early turns" below 400 ft AGL because of close-in obstacles:

Takeoff minimums are usually at least 300-1
Procedure says "turn as soon as practicable"
This is a mandatory turn—not optional

IFR Departure Briefing Template

Having a consistent departure briefing format helps you catch issues before they become problems. Use this pattern:

Runway, heading, initial altitude, nav plan
Required climb gradient ft/NM → required ft/min at expected groundspeed
Departure procedure type: Diverse / ODP / SID / vectors
When I can turn (altitude) and where
What if: engine issue, can't maintain gradient, need to return

The One-Liner Format

For a quick reference you can memorize and say out loud:

"15, 153°, 3000, 370 to 700—that's 555 fpm at 90 kt—left to IGN, ODP."

Format: Runway, heading, altitude, gradient/end altitude—required fpm at GS—turn direction/fix, procedure type

Practice Building Briefings

Use this tool to practice structuring your departure briefings. Enter procedure information and see both the full format and the one-liner version.

Practice Tool Only: Build practice briefings to master the departure briefing format. Always verify procedure details from current charts before any real flight.

Departure Briefing Builder

Departure Information

Airport

Runway

Heading (°)

Initial Altitude (ft)

Gradient (ft/NM)

Gradient Ends At (ft)

Leave empty if standard continues

Expected Groundspeed (kt)

Procedure Type

Turn

To Fix/Heading

At (ft AGL)

Generated Briefing

Required Climb Rate

300 ft/min

at 90 kt GS for 200 ft/NM

Full Briefing

Runway: [RWY], Heading: [HDG]° Initial Altitude: 3,000 ft Climb Gradient: 200 ft/NM Required Climb Rate: 300 ft/min at 90 kt GS Procedure: Diverse Departure

One-Liner Format

RWY, HDG°, 3,000, 200, → 300 fpm @ 90kt, DIV

Format: RWY, HDG, ALT, Gradient → FPM @ GS, Turn, Procedure

Practice Quiz

Test your climb gradient math with these practice scenarios based on real departure procedures. Switch between Quiz mode (test yourself) and Learn mode (see the answers immediately).

Climb Gradient Practice Quiz

Score: 0/0

Scenario 1 of 8

KLGA (LaGuardia)

Runway 22

200 ft/NM

A standard diverse departure in the NYC area.

Gradient

200 ft/NM

Until

2,000 ft

Groundspeed

120 kt

What climb rate (ft/min) is required to meet a 200 ft/NM gradient at 120 kt groundspeed?

Quick Reference:

Required FPM = (GS × ft/NM) ÷ 60

Achievable ft/NM = (FPM × 60) ÷ GS

Practice in the Simulator

Understanding the math is step one. Actually flying these departures under the hood, managing airspeed, monitoring your VSI, and executing procedure turns—that's where the real learning happens.

Our FAA-certified AATD simulator lets you practice departures from challenging airports with tight gradients, high density altitudes, and terrain—all without the consequences of getting it wrong in the real airplane. Use the calculator and quiz above to prepare, then put it into practice in the sim.

Whether you're working toward your instrument rating in NYC, need to maintain your instrument currency, or are preparing for airline training, practicing these concepts in a simulator environment allows you to perfect procedures before applying them in the aircraft.