Unvocalized قدر hides several related verbs and nouns. On this page, the core verb is Form I قَدَرَ / يَقْدِرُ “be able, have power,” usually with على. Dictionaries also record قَدَرَ / يَقْدُرُ and قَدِرَ / يَقْدَرُ as ability variants, alongside older transitive Form-I senses involving measure, allotment, or decree. Modern قَدَّرَ / يُقَدِّرُ “estimate, appreciate, assess” is Form II and must keep its shadda.
That separation matters because English can, estimate, and decree do not tell you which Arabic stem or complement to choose. For everyday formal “be able to,” استطاع أن is the broadest default; قدر على foregrounds capacity, command, or success in overcoming something.
Review the sound-stem baseline on the Form-I overview, then compare the broader neutral ability verb on the استطاع reference page.
Lookup card: the Form-I ability verb
| Item | Verified form | Use |
|---|---|---|
| root and Form | ق-د-ر، Form I | sound triliteral verb |
| perfect | قَدَرَ / قَدِرَ | he was able / had power; قَدَرَ is the production default here |
| imperfect | يَقْدِرُ / يَقْدُرُ؛ يَقْدَرُ with قَدِرَ | he is able; all three lexical pairings are recorded |
| imperative | اِقْدِرْ / اُقْدُرْ؛ اِقْدَرْ with قَدِرَ | corresponding variants; rare for ordinary ability |
| verbal nouns | قُدْرَةٌ، مَقْدِرَةٌ | ability, power, capacity |
| active participle | قَادِرٌ | able, capable; normally with على |
| passive participle | مَقْدُورٌ | within power, destined; sense depends on complement |
| Form-I passive | قُدِرَ — يُقْدَرُ | was/is measured or allotted; limited in contemporary use |
For active production, learn قَدَرَ — يَقْدِرُ — قُدْرَةً — قَادِرٌ عَلَى. The pairings قَدَرَ / يَقْدُرُ and قَدِرَ / يَقْدَرُ are also standard, particularly in older or elevated material; unvocalized قدر / يقدر does not show which reading a writer intends. The imperative is morphologically available, but the command “be able!” is rarely useful. Commands normally name the desired action instead.
قدر الفريق على استعادة معظم البيانات من النسخة الاحتياطية.
qadara l-farīqu ʿalā stiʿādati muʿẓami l-bayānāti mina n-nuskhati l-iḥtiyāṭiyya.
The team managed to recover most of the data from the backup. (Formal.)
لا يقدر هذا المحرك على حمل وزن إضافي في المنحدرات.
lā yaqdiru hādhā l-muḥarriku ʿalā ḥamli waznin ʾiḍāfiyyin fī l-munḥadarāt.
This engine cannot carry additional weight on slopes. (Formal technical register.)
Ability with على
The most characteristic frame is قَدَرَ على + noun or verbal noun. The preposition presents an action, difficulty, or opponent as something within the subject’s power. English normally uses can or manage to and has no equivalent preposition.
لم يقدر الطبيب على تحديد سبب الألم من الفحص الأول.
lam yaqdiri ṭ-ṭabību ʿalā taḥdīdi sababi l-ʾalami mina l-faḥṣi l-ʾawwal.
The doctor could not determine the cause of the pain from the first examination. (Formal.)
يقدر النظام على معالجة ألف طلب في الدقيقة.
yaqdiru n-niẓāmu ʿalā muʿālajati ʾalfi ṭalabin fī d-daqīqa.
The system can process one thousand requests per minute. (Formal technical register.)
كان قادرا على المغادرة، لكنه بقي ليساعد زملاءه.
kāna qādiran ʿalā l-mughādarati, lakinnahu baqiya liyusāʿida zumalāʾah.
He was able to leave, but he stayed to help his colleagues. (Formal; adjective capable state.)
The active participle قادر على is often more idiomatic than finite يقدر على when ability is treated as a stable property: الشركة قادرة على التوسع “the company is capable of expanding.” With a specific achieved event, past قدر على or استطاع is natural.
Ability with أن
Formal Arabic also attests قَدَرَ أن + imperfect subjunctive, particularly when the complement is a full proposition rather than a compact activity noun. It is grammatical, though قدر على + maṣdar and استطاع أن give learners more predictable default frames.
لم يقدر أن يشرح موقفه قبل انتهاء الجلسة.
lam yaqdir ʾan yashraḥa mawqifahu qabla ntihāʾi l-jalsa.
He was unable to explain his position before the session ended. (Formal.)
قدرت اللجنة أن تجمع بين المقترحين في صيغة واحدة.
qadarati l-lajnatu ʾan tajmaʿa bayna l-muqtaraḥayni fī ṣīghatin wāḥida.
The committee managed to combine the two proposals in one formulation. (Formal.)
Do not mix the two frames mechanically: use قدر على إنجاز المهمة or قدر أن ينجز المهمة. Adding على directly before أن is possible in some expanded constructions but is not the clean learner default for this verb.
قدر and استطاع
استطاع is the neutral all-purpose formal verb for practical ability and often means “managed to” in the affirmative past. قدر على places the enabled action or obstacle under the subject’s power and can sound slightly more forceful or elevated. In many contexts both are truthful and natural; the difference is perspective, not a categorical division between “physical” and “mental” ability.
استطاعت الشركة فتح فرع جديد، لكنها لم تقدر على جذب عدد كاف من الموظفين.
istaṭāʿati sh-sharikatu fatḥa farʿin jadīdin, lakinnahā lam taqdir ʿalā jadhbi ʿadadin kāfin mina l-muwaẓẓafīn.
The company managed to open a new branch, but it could not attract enough employees. (Formal.)
Several spoken dialects use reflexes of قدر as the everyday modal “can.” That does not make finite يقدر على wrong in MSA, but formal prose uses استطاع، يمكن، قادر على more broadly and does not import every dialectal complement pattern.
Measure, allot, and decree: Form I versus Form II
Form I قَدَرَ has older and elevated transitive senses: determine a measure, apportion something, plan a matter, or—in reference to divine action—decree or allot. These uses are found in Classical, Quranic, religious, and literary language. Their maṣdar may be قَدْر or قَدَر depending on sense.
قدر الله للإنسان رزقه وأجله.
qadara llāhu lil-ʾinsāni rizqahu waʾajalah.
God allotted to the human being his provision and lifespan. (Religious/elevated; Form I.)
Contemporary Form II قَدَّرَ / يُقَدِّرُ / تَقْدِيرًا carries the ordinary meanings “estimate, assess, value, appreciate,” and also “decree” in many formal or religious contexts. The shadda is part of the stem, not optional emphasis.
قدر المهندس تكلفة الإصلاح بمئتي ألف دولار.
qaddara l-muhandisu taklifata l-ʾiṣlāḥi bimiʾatay ʾalfi dūlār.
The engineer estimated the repair cost at two hundred thousand dollars. (Formal; Form II.)
نقدر تعاونكم وصبركم خلال فترة الانتقال.
nuqaddiru taʿāwunakum waṣabrakum khilāla fatrati l-intiqāl.
We appreciate your cooperation and patience during the transition period. (Formal correspondence; Form II.)
The common passive قُدِّرَ له أن... “it was destined for him to...” contains a shadda and is Form II. Form-I passive قُدِرَ is separately possible but far less central in contemporary prose. Unvocalized text hides this distinction, so grammatical context and meaning must recover it.
High-frequency collocations
| Collocation | Meaning and register |
|---|---|
| قَدَرَ عَلَى الشَّيْءِ | be able to master/do something (formal) |
| قَدَرَ أَنْ يَفْعَلَ | be able to do (formal; attested alternative) |
| قَادِرٌ عَلَى | capable of (neutral formal) |
| فِي مَقْدُورِهِ | within his power (formal) |
| قَدْرَ الِاسْتِطَاعَةِ | to the extent possible (formal) |
| قَدَّرَ التَّكْلِفَةَ | estimated the cost (Form II, formal) |
| قَدَّرَ جُهُودَهُ | appreciated his efforts (Form II, formal) |
Common Mistakes
Dropping على from the core ability frame
❌ لم يقدر إلى حل المشكلة وحده.
Incorrect for ability—the established preposition is على, not إلى.
✅ لم يقدر على حل المشكلة وحده.
lam yaqdir ʿalā ḥalli l-mushkilati waḥdah.
He could not solve the problem alone.
Using the wrong preposition with Form-II “estimate”
❌ قدر الخبير الخسائر على مليون دولار.
Incorrect for ‘estimated the losses at’—Form II قدّر takes the amount with بـ in this frame, not على.
✅ قدر الخبير الخسائر بمليون دولار في تقريره الأولي.
qaddara l-khabīru l-khasāʾira bimilyūni dūlārin fī taqrīrihi l-ʾawwaliyy.
The expert estimated the losses at one million dollars in his preliminary report.
Treating قدر and استطاع as different physical-versus-mental modals
❌ لا يستعمل استطاع إلا للقدرة الجسدية.
Incorrect—استطاع covers physical, mental, technical, and situational ability.
✅ استطاع الباحث تفسير النتيجة المعقدة.
istaṭāʿa l-bāḥithu tafsīra n-natījati l-muʿaqqada.
The researcher managed to explain the complex result.
Key Takeaways
- Form-I ability قَدَرَ / يَقْدِرُ normally takes على + noun or maṣdar; قدر أن + subjunctive is also attested.
- قادر على is especially natural for stable capability.
- استطاع is the broad unmarked formal ability verb; قدر على often foregrounds power or mastery.
- Form II قَدَّرَ supplies ordinary modern “estimate, assess, appreciate” and must keep its shadda.
- Older Form-I measure/allot/decree senses are real but mainly elevated, religious, literary, or lexicographic in contemporary reading.
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Start learning Arabic →Related Topics
- استطاع — be able with أن and an irregular Form X hollow stemB1 — Conjugate استطاع, express ability with أن or a verbal noun, and distinguish capability from successful achievement and قدر على.
- يجب — express obligation impersonally with على and أنB1 — Build precise obligation clauses with يجب أن and يجب على شخص أن without conjugating يجب like English must.
- كان — beA2 — Reference the hollow verb كان across its full paradigm, copular and existential senses, predicate case, conditionals, and high-frequency collocations.
- Ability and ObligationA2 — Distinguish personal ability, impersonal possibility, firm obligation, and formal advisability with أستطيع، يمكن، يجب، and ينبغي.
- Form I: The Lexical BaseA2 — Learn why Form I must be stored through verified principal parts, stem-vowel class, valency, and maṣdar rather than one universal pattern.