ISRO UDC Syllabus 2026: Written Test and Skill Test Guide

The ISRO UDC syllabus covers two stages: a computer-based written test in General English, Quantitative Aptitude, General Intelligence and Reasoning and General Knowledge, and a Computer Literacy Test in MS Word, Excel and PowerPoint. Both are set by the ISRO Centralised Recruitment Board (ICRB) under Advertisement No. ISRO:ICRB:01(A-JPA):2026.

ISRO publishes a short outline for each part in the advertisement's annexures rather than a full topic list. The topic tables below expand that official outline using the question types that appear in clerical recruitment exams of this level. Use them as a working checklist, not as an official list, and check the official ISRO ICRB 2026 advertisement for the exact wording.

Table of Contents

ISRO UDC Syllabus at a Glance

The marking, stage rules and timing are explained in detail in the ISRO UDC exam pattern guide.

Rules That Shape Your Preparation

A few official rules change how you should spread your time across the syllabus.

• Negative marking: Each wrong answer in the written test costs 0.25 marks, so accuracy matters as much as coverage.

• Qualifying marks: You need 50% in the written test as a UR candidate and 40% in a reserved category against reserved vacancies.

• Merit from the written test only: Skill test marks are not added. Your rank depends on your score out of 200.

• Reasoning breaks ties: When written scores are equal, higher marks in General Intelligence and Reasoning rank you higher.

• Skill test is pass or fail: UR candidates need 60% and reserved candidates need 50% in the Computer Literacy Test.

Older pages may still show 22 UDC vacancies and 16 August as the last date. The 11 August 2026 corrigendum revised these to 23 posts and 20 August, and the syllabus and pattern were not changed for UDC.

General English Syllabus

The official outline names comprehension, grammar, correct use of words, and idioms and phrases. In practice, this section rewards steady reading and a firm grip on basic grammar rules.

English is usually the fastest section to finish. If you can answer most of it accurately in about 25 minutes, you gain time for Quant and Reasoning.

Quantitative Aptitude Syllabus

The outline lists number systems, percentages, profit and loss, ratios, averages, interest, time and work, geometry, mensuration, trigonometry, algebra, and statistics with data interpretation. It splits naturally into three blocks.

Arithmetic

• Number basics: Number system, divisibility, HCF and LCM, decimals and fractions, simplification and approximation, surds and indices.

• Percentage-based topics: Percentage, profit and loss, discount, simple and compound interest.

• Ratio-based topics: Ratio and proportion, partnership, mixture and alligation, ages, averages.

• Time-based topics: Time and work, pipes and cisterns, time, speed and distance, boats and streams, trains.

Advanced Mathematics

Statistics and Data Interpretation

Expect questions on mean, median and mode, along with data sets presented as tables, bar graphs, line graphs and pie charts. Data interpretation questions usually come in sets, so a strong grip on percentages and ratios pays off twice here.

General Intelligence and Reasoning Syllabus

The official outline covers verbal and non-verbal reasoning, including series, analogies, coding-decoding, seating and ranking, direction sense and puzzles. Because this section decides ties, it deserves more attention than its 50 marks suggest.

General Knowledge Syllabus

The outline names current affairs, history, culture, geography, science, polity and economy. For an ISRO post, questions on space science and the organisation's own missions are also a sensible area to cover.

Static GK can be built over time, but current affairs needs a daily habit. A one-page monthly summary is easier to revise than a large stack of newspaper cuttings.

Computer Literacy Test Syllabus

The skill test is practical. You perform tasks on a computer within 75 minutes, and the outline in Annexure-IV of the advertisement lists what each application covers.

MS Word (35 Marks)

• Files and editing: Creating, opening, saving and printing documents; cut, copy, paste, find and replace.

• Formatting: Fonts, paragraph alignment, line spacing, bullets and numbering, headers, footers and page numbers.

• Page and tables: Page setup, margins and orientation; inserting tables and editing rows, columns and borders.

• Tools: Spell check, templates, mail merge and common shortcut keys.

MS Excel (35 Marks)

• Worksheet basics: Entering and editing data, inserting and deleting rows and columns, cell formatting.

• Formulas and functions: Relative and absolute cell references, SUM, AVERAGE, COUNT, MIN, MAX, IF and similar functions.

• Data handling: Sorting, filtering and data validation.

• Charts and printing: Creating and formatting charts, setting print areas and page layout.

MS PowerPoint (30 Marks)

• Creating presentations: New slides, layouts, design templates and slide backgrounds.

• Adding content: Text boxes, images, shapes, tables and charts.

• Finishing: Headers and footers, slide numbers, basic formatting and saving.

Practise on a recent version of MS Office, and learn keyboard shortcuts for common actions. They save a lot of time when tasks are spread across three applications.

Which Topics to Prioritise

The table gives a starting order based on how quickly each area turns study time into marks. Adjust it after your first full mock.

Common Syllabus Mistakes to Avoid

• Treating GK as an afterthought: General Knowledge carries the same 50 marks as Quant. Leaving it to the last month usually means weak current affairs and guesswork, which negative marking punishes.

• Over-studying advanced maths: Geometry and trigonometry are in the outline, but arithmetic and data interpretation are the foundation the other topics build on. Secure those first, then move to advanced topics.

• Skipping non-verbal reasoning: Mirror images, figure counting and paper folding are quick marks once you practise them, yet many candidates leave them out.

• Ignoring the skill test until the result: The gap between the written test result and the skill test can be short. Basic MS Office practice during written test preparation keeps you ready.

• Studying from a single long list: A topic list tells you what to cover, not how well you know it. Test each chapter as you finish it, and let your mock analysis decide what to revise.

How to Cover the ISRO UDC Syllabus

The plan below assumes about 14 weeks for the written test. If you took the 2026 written test and expect to be shortlisted, start the skill test phase now, because the test is tentatively scheduled for 25 October 2026.

1. Weeks 1 to 6, concepts: Cover arithmetic and reasoning basics, revise grammar rules, and build a daily 20-minute reading habit. Solve topic-wise questions after each chapter.

2. Weeks 3 to 14, current affairs: Spend 30 to 40 minutes a day on news and maintain monthly notes. Add static GK one area at a time.

3. Weeks 7 to 10, advanced topics and sectional tests: Finish algebra, geometry, trigonometry and data interpretation. Take timed sectional tests twice a week to build speed.

4. Weeks 11 to 14, full mocks: Attempt two or three full-length tests a week in 150 minutes, analyse each one on the same day, and revise from an error log.

5. Skill test phase, 3 to 4 weeks: Practise one Word, one Excel and one PowerPoint task daily under a timer, focusing on formulas, tables and formatting.

Topic tests help you check each chapter as you finish it, while full-length tests show whether you can hold accuracy for 200 questions.

Finally, solve the official ISRO Assistant 2023 question paper under exam conditions. It shows the real level of questions for this clerical cadre better than any topic list.