Examples
Meaning
〜なら sets a condition based on a topic or assumption. 〜たら sets a condition based on something happening or being completed. Both can mean if, but the logic is different.
Formation
〜なら often follows a noun, な-adjective, or plain clause. 〜たら follows the past plain form plus ら.
Usage
Use 〜なら when you respond to a topic and give advice, information, or a recommendation. Use 〜たら when you talk about what will happen after an event or when a condition is satisfied.
Nuance
〜なら often feels like if that is what you mean or if that is your plan. 〜たら feels more like when that happens or once that happens.
Comparison
大阪に行くなら、たこ焼きを食べてください gives advice based on the topic of going to Osaka. 大阪に着いたら、連絡してください asks for an action after arriving in Osaka. Reversing them changes the meaning or sounds unnatural.
Common Mistakes
A common mistake is using 〜なら when the sentence is really about time order. If the meaning is after you arrive, use 〜たら instead of 〜なら.
Related Grammar
〜なら
〜なら is used when making a condition based on a topic, assumption, or information already mentioned. It often appears in advice and recommendations.
〜たら
〜たら is a flexible conditional pattern used for if, when, and after. It is common in daily conversation and works well with plans and requests.
〜と
〜と is a conditional pattern used for natural results, automatic actions, directions, and repeated facts.
〜ば
〜ば is a conditional pattern meaning if. It often focuses on the condition that must be true for something else to happen.
と・ば・たら・ならの違い
This comparison page organizes the four major Japanese conditionals と, ば, たら, and なら so learners can choose the right one.