Yes, only. You can upgrade to a higher plan or add accounts anytime during your contract period (changes take effect immediately).
The difference is calculated on a daily basis for the remaining period of your current contract period, and you pay the full amount at once.
To downgrade your plan, reduce accounts, change your contract period, or cancel your subscription, you must use the "Next renewal plan settings" screen and complete the process on your next renewal date, not during the contract period. Please note that we do not issue refunds for downgrades.
For details on how to complete these procedures, please refer to Paid plan contracts, billing, renewals, and cancellations.
Daily proration calculation method
The difference for upgrades and account additions is calculated using the following formula:
Difference (tax excl.) = (Monthly fee for new plan × contract period duration – Monthly fee for current plan × contract period duration) × Remaining days ÷ Total days in contract period
- "Amount per contract period" is monthly fee × 12 months for annual contracts, or monthly fee × 3 months for 3-month contracts.
- "Total days" is the number of days in your current subscription period (from start date to end date).
- "Remaining days" is the number of days from the start date through your subscription end date.
- Fractional amounts (decimals) are rounded down.
You will be charged only the difference; your current contract period and next renewal date remain unchanged. The new plan applies to the remainder of your contract period starting from the start date.
Billing amount case study
Using Lite plan (1-year contract)
Subscription period: January 25, 2025 – January 24, 2026
Upgrade to Pro plan on April 15, 2025
Amount per contract period
- Lite (annual contract): 10,000 yen/month × 12 months = 120,000 yen
- Pro (annual contract): 50,000 yen/month × 12 months = 600,000 yen
- Difference (full amount): 600,000 yen – 120,000 yen = 480,000 yen
Days
- Total days in contract period: January 25, 2025 – January 24, 2026 = 365 days
- Remaining days: April 15, 2025 – January 24, 2026 = 285 days
Billing calculation
- Calculation: 480,000 yen × 285 days ÷ 365 days
- 374,794.52… → Rounded down: 374,794 yen (tax excl.)
Total billing amount
- Difference (tax excl.): 374,794 yen
- Consumption tax (10%): 37,479 yen
Total: 412,273 yen (tax incl.)
※ When you actually proceed with the process, the Dive screen will display the difference and calculation basis (your current plan, new plan, full amount difference, and daily proration amount), and you can confirm the details before proceeding.