Flag Size Calculator
Enter the height of your flagpole, whether it stands in the ground or angles from a wall, and the flag's proportions. The calculator suggests a flag size and the nearest standard size.
- Pole height to flag size
- Ground or wall poles
- Standard sizes
Measure the pole above the ground. For wall poles, measure the pole's full length.
A flag should be about a quarter as long as the pole is tall. That simple rule keeps a flag in proportion. Too small and it looks lost at the top. Too large and it can tangle, touch the ground or put strain on the pole in wind. Wall-mounted poles take a flag about half the pole length.
Flag and flagpole chart
In-ground poles. Search for a height.
| Pole (ft) | Pole (m) | Flag (ft) | Flag (cm) |
|---|---|---|---|
| 15 | 4.6 | 2 × 3 or 3 × 5 | 90 × 150 |
| 20 | 6.1 | 3 × 5 or 4 × 6 | 120 × 180 |
| 25 | 7.6 | 4 × 6 or 5 × 8 | 150 × 240 |
| 30 | 9.1 | 5 × 8 | 150 × 240 |
| 35 | 10.7 | 6 × 10 | 180 × 300 |
| 40 | 12.2 | 6 × 10 or 8 × 12 | 240 × 360 |
| 50 | 15.2 | 8 × 12 or 10 × 15 | 300 × 450 |
Sizes are given as hoist (height) × fly (length). Use the next size down for very exposed, windy sites.
Pole height and flag size
In-ground pole, 2:3 flag. Slide the pole height.
The person in the drawing gives a sense of scale. A 6 m pole carries a flag about the length of a person.
How to choose a flag size
From the pole. Step through it.
Measure the pole
Height above ground.
Flags fly better and last longer in the right size. A big flag in strong wind frays quickly at the fly end.
Fabric choices
Flag materials. Compare them.
Light, bright and flies in a gentle breeze.
Heavy and hard-wearing, looks like cotton.
Shiny, dries fast and flies easily.
Bring flags down in storms. Even the strongest fabric wears out fast in a gale.
Before ordering a flag
Quick checks. Tick each item.
Tick each item as you go.
Check the correct proportions for national flags. The UK Union Flag is 1:2, while many shops sell it at 3:5.
What you get
Sizes in every unit. Each tile explains one result.
Hoist × fly in metres.
For US and UK suppliers.
Nearest stock size.
Flag proportions.
Square metres of fabric.
The fly is the length from pole to free end. The hoist is the height along the pole.
Frequently Asked Questions
No question matches that search.
What size flag for a 20 ft pole?
3 × 5 ft or 4 × 6 ft.
What size flag for a 6 m flagpole?
About 1 × 1.5 m (2:3), or 90 × 150 cm.
What is the rule for flag size?
The fly should be about a quarter of the pole height.
What size flag for a wall-mounted pole?
About half the pole length for the fly. A 1.5 m pole takes a 3 × 5 ft flag.
What do hoist and fly mean?
Hoist is the height along the pole; fly is the length out from it.
What ratio is the US flag?
10:19 officially, but 3:5 is most common for sale.
Should I use a smaller flag in wind?
Yes. One size down lasts longer on exposed sites.
A flag in proportion
Take a quarter of the pole height for the fly, apply the flag's proportions and round to a standard size. The flag will look right and fly well for years.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.