Free tool
eSIM data calculator: how much data do you need for your trip?
Add the country, the days, and a normal day of maps, chat and video to see the gigabytes and what they cost on that country's pay-as-you-go rate.
The formula
GB = days × GB/day × buffer, with the buffer set to 1.15 (15% extra). Cost = GB × that country's per-GB price from the rates data. 1 GB = 1000 MB.
GB/day is the daily total in megabytes divided by 1,000. The cost is that recommended total times the per-GB price published for the country on the rates page. Silent eSIM bills it from a USD balance. You are not buying a fixed pack of gigabytes.
A week in Spain, typical use
Same preset the calculator opens on: 7 days, typical use in 🇪🇸 Spain. The gigabytes are the figures above. The price, when it is shown, is Spain's current rate from the rates catalogue.
| Destination | Spain |
|---|---|
| Trip | 7 days, typical use |
| Daily use | 789 MB (0.789 GB) |
| Before buffer | 5,523 MB (5.523 GB) |
| Buffer (15%) | 828.45 MB (0.828 GB) |
| Recommended | 6,351.45 MB (6.351 GB) |
| Rate | $1.08 per GB |
| Balance used | about $6.86 |
Prices checked 26 October 2026.
How we estimate
These are typical public estimates. Your apps, quality settings and background updates will differ. The calculator uses the single figure in the middle column, and nowhere else.
| Activity | Figure we use | Where that sits |
|---|---|---|
| Maps and navigation | 10 MB per hour | Inside the usual 5–20 MB/hour band for live maps. Offline maps are about 0 MB while you follow them. |
| Text messages | 0.02 MB each | A short WhatsApp, Signal or iMessage is tiny. This leaves a little room for delivery overhead. |
| Photos in chat | 0.3 MB each | Inside the usual 0.1–0.5 MB band for a compressed photo, not the original from the camera roll. |
| Social scrolling | 150 MB per hour | Inside the usual 100–200 MB/hour band. TikTok and Reels run higher than a still-photo feed. |
| Video, SD | 700 MB per hour (0.7 GB) | Inside the usual 0.5–0.7 GB/hour band. |
| Video, HD | 1500 MB per hour (1.5 GB) | The low end of the usual 1.5–3 GB/hour band. Full 1080p can sit higher. |
| Video calls | 1000 MB per hour (1 GB) | Inside the usual 0.5–1.5 GB/hour band for a one-to-one call. |
| Hotspot | 150 MB per hour | Ordinary laptop browsing and email. It depends what the laptop does. Count video on the video row. |
A few things that actually save data
Download offline maps
Grab the area on Wi-Fi before you fly. Following an offline map is about 0 MB. The maps row is for live turn-by-turn.
Turn off auto-play and background updates
Social apps burn through the social row if video starts on its own. App stores and system updates belong on Wi-Fi.
Use Wi-Fi for backups
A camera-roll backup is far larger than the compressed photos in the chat row. Wait until you are on Wi-Fi.
Limits
- Trip length in the calculator runs from 1 to 90 days.
- Hotspot is counted at 150 MB per hour of ordinary browsing. If the laptop plays video, add those minutes on the video row instead.
- Photo backups, app updates and the download of offline maps are not in the sliders. Do those on Wi-Fi.
- This is not a fixed gigabyte pack. Silent eSIM deducts data from a USD balance at the live per-GB rate for the country you are standing in. That rate can change. Credit you do not spend stays on the eSIM.
- The 15% buffer is room for a busier day. It is not a cap, and it is not a promise about coverage or speed.
Questions
How much data do I need for a week?
On the typical preset this page opens with, 7 days is 789 MB a day and 6.351 GB after the 15% buffer. That preset is an hour of maps, 50 texts, 10 photos, 40 minutes of social scrolling, 30 minutes of standard-definition video, 15 minutes of video calls and half an hour of hotspot. The country changes the price, not the gigabytes.
Does a hotspot use more data?
It depends what you plug in. Hotspot is counted here at 150 MB per hour, which is ordinary browsing and email on a laptop. Video on that laptop belongs on the video row. Hotspot is included on every Silent eSIM, with no extra fee.
What if I run out?
Data pauses when the balance hits zero. There is no overage charge. Top up from any browser and the same eSIM is back online in seconds. You do not reinstall it, and you do not get a new QR code. Credit you do not spend stays on the eSIM and does not expire.
Are these figures exact?
No. They are typical public estimates, and real use moves with app settings and whatever updates in the background. The calculator and the how-we-estimate table use one figure per activity, then add 15%.
Do offline maps use data?
Following a map you have already downloaded is about 0 MB. The download itself can be large, so get it on Wi-Fi before you leave. Live navigation in this calculator is 10 MB per hour.
Does unused credit expire?
No. Silent eSIM takes the cost out of a USD balance at the country's per-GB rate as you go. You are not buying a bundle of gigabytes that runs out on a date, and credit left over from the trip stays on the eSIM.
Take the balance with you
The calculator is only an estimate. When you are ready, start an eSIM and spend the balance in whichever country you are actually in.
Get an eSIM