Installment and instalment mean the same thing. The difference is spelling style. Installment is American English. Instalment is British English. Both refer to a part of a larger payment, story, or series.
Examples:
- I paid the phone bill in one installment. (US)
- I paid the phone bill in one instalment. (UK)
- The show released its final installment last week.
- This is the last instalment of the book series.
The meaning never changes. Only the region changes the spelling.
English spelling can feel tricky, especially when one word has two correct forms. That is exactly why many people search for installment vs instalment. You may see one spelling in bank documents and another in British books. This creates confusion. Is one wrong? Does the meaning change? Which one should you use in school, business, or online writing?
The confusion grows when people also mix up instalment and installation, or wonder if installmental payment is correct. Some see instalment plan on a UK website but bank installment on an American app. The good news is simple: both spellings are correct, but they belong to different versions of English. This guide explains instalment definition, instalment plural, usage rules, and real-life examples in clear, easy English.
The Origin of Installment vs Instalment

The word comes from the verb install, which means to place or set something in position. In old French, a similar word meant “to put in place.” Over time, English speakers used the term for payments made in parts.
British English kept the shorter spelling pattern, so instalment became standard in the UK. American English often adds double consonants before certain endings, which led to installment.
Language changes over time. Printing rules, dictionaries, and schools shaped spelling in different countries. That is why we now have two accepted forms. The instalment definition in both regions is the same: one of several equal payments or parts of something released over time.
The instalment plural form is instalments in British English and installments in American English.
British English vs American English Spelling
English spelling rules differ between regions. The extra “l” in installment follows American spelling habits. British English prefers one “l” before “-ment.”
| Feature | American English | British English |
|---|---|---|
| Standard spelling | installment | instalment |
| Plural form | installments | instalments |
| Used in | USA, Philippines (often), some global tech apps | UK, Pakistan, India, Australia, Canada (often) |
| Seen in banks | bank installment | bank instalment |
| Seen in shopping | installment plan | instalment plan |
Both are correct. Choice depends on your audience.
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Which Spelling Should You Use?
Use the version your readers expect.
- Writing for the USA → use installment
- Writing for the UK or Commonwealth → use instalment
- Writing for global business → follow brand style
- Academic writing → follow school guide
- Banking apps in America say bank installment
- UK finance sites say instalment payment
Oxford Dictionary follows British spelling, so it uses instalment. American dictionaries list installment.
Consistency matters more than choice. Do not mix both spellings in one document.
Common Mistakes with Installment vs Instalment
Many people confuse spelling and meaning.
Mistake 1: Mixing with installation
Installation means setting up equipment. An installment is a payment part.
Wrong: I paid the laptop installation.
Right: I paid the laptop installment.
Mistake 2: Writing installmental payment
Installmental payment is not standard English. Use instalment payment or installment payment.
Mistake 3: Mixing spellings in one text
Choose one style only.
Mistake 4: Wrong plural
Instalment plural → instalments
Installment plural → installments
Mistake 5: Thinking one is incorrect
Both are correct in their region.
Installment vs Instalment in Everyday Examples

Emails:
Please pay the first installment by Monday.
Your final instalment is due tomorrow.
News:
The final installment of the movie earned millions.
The last instalment of the series airs tonight.
Social Media:
Just paid my last installment, feeling free!
Only one instalment left on my loan.
Formal Writing:
The customer agreed to an installment plan.
The buyer selected an instalment plan.
Banking:
My bank installment is auto-deducted.
My bank instalment goes out every month.
Installment vs Instalment – Google Trends & Usage Data
Search patterns show strong regional use. People in the United States mostly search installment spelling UK when confused about British style. In the UK and nearby countries, instalment plan and instalment payment are more common.
Financial services often follow local language rules. International companies may switch spelling based on user location. Education systems also shape spelling habits.
Online shopping has increased global mixing. A UK user may see installment plan on an American website. That is why understanding both forms is helpful today.
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Comparison Table: Keyword Variations
| Phrase | Meaning | Region |
|---|---|---|
| installment | payment part | US |
| instalment | payment part | UK |
| installment plan | pay in parts | US |
| instalment plan | pay in parts | UK |
| bank installment | bank payment part | US |
| instalment payment | payment portion | UK |
| installment spelling UK | question about British form | Search term |
| instalment synonym | payment, portion, share | Both |
FAQs
1. How do you spell installment in Oxford Dictionary?
Oxford uses instalment, the British form.
2. What is the difference between installment and installation?
Installment means a payment part. Installation means setting something up.
3. Is it monthly installment or instalment?
Both are correct. Choose based on region.
4. Is installmental payment correct?
No. Use installment payment or instalment payment.
5. What is the instalment definition?
One of several parts paid or released over time.
6. What is the instalment plural?
Instalments in UK English. Installments in US English.
7. Is instalment synonym the same as payment?
Yes, it can mean payment, portion, or share.
Conclusion
The confusion around installment vs instalment comes from regional spelling rules, not meaning. Both words describe one part of a series of payments, stories, or releases. The instalment definition stays the same in every country. Only the spelling changes.
American English prefers installment, while British English uses instalment. Oxford dictionaries follow the British form. Financial services, schools, and companies usually match local spelling rules. That is why you may see bank installment in the US but instalment plan in the UK.
Avoid mixing the word with installation, which has a different meaning. Do not use installmental payment, as it is not standard English. Remember the correct instalment plural forms and keep your spelling consistent in one document.
Understanding both forms helps in global communication, online shopping, banking, and academic writing. When unsure, check your audience and follow their language style. Simple choice, clear writing, correct usage.

Tessa Hadley, a reflective voice at SimileHub.com, transforms everyday moments into vivid imagery, guiding writers to create powerful, expressive comparisons.








