Statul online a personal vision
100%
RO EN HU

Research · Choosing a font

Choosing a font: criteria for the right font

This research sets out the criteria for choosing the font of a design system for the Romanian state. It describes the situation on 22 October 2026. Here you will find:

0. Summary in eight points

  1. There is no single "most legible" font. Studies show which features help:
    • lowercase letters that are tall enough;
    • open shapes;
    • letters that are wide enough, with space between them;
    • characters that are easy to tell apart.
  2. The characters most easily confused are capital I, lowercase l and the digit 1, then capital O, the digit 0 and lowercase o. The German legibility standard DIN 1450 and the US government's accessibility guide both require them to be distinct.
  3. "Dyslexia fonts" do not help. Wider spacing does, and users must be able to increase it.
  4. In Romania, the font has to write many languages correctly. The state applies the European Charter for Regional or Minority Languages to 20 languages, written in the Latin, Cyrillic, Greek, Armenian and Hebrew alphabets. This rules out most of the fonts presented as "highly legible", including Sora, the font used by ROeID, Romania's electronic identity service.
  5. A font of your own has a price. States that made their own font cannot pass it on to suppliers and partners, who end up using Arial. Newer systems choose open-licence fonts.
  6. The font is hosted on the state's own servers, not loaded from Google.
  7. Of the fonts checked, Source Sans 3 and IBM Plex Sans meet the criteria best. The final choice should be made together with the General Secretariat of the Government (SGG), after a short test with people.
  8. Section 5 gathers the criteria into a list that can be used for any font choice.

1. What studies and standards say

1.1 Characters that are easy to confuse

The German standard DIN 1450 asks for easily confused characters to be avoided and names I, l, 1 and O, 0. The US government's accessibility guide (digital.gov) says: "I, l, and 1 are distinct. 0 and O are distinct." A review of studies on confused letters adds other pairs: rn and m, cl and d, B and 8, 5 and S. In one of the studies cited there, a digit 1 drawn with a flag and a base was recognised correctly 97% of the time, against 43% without the base.

The I/l/1 and O/0 pairs are the ones standards and guidance agree on. Studies carried out directly on interfaces are, however, few.

Roboto the Android phone font I and l look the same

Inter default I and l look the same

IBM Plex Sans default I, l and 1 differ

Source Sans 3 with serifed I and slashed 0 I, l and 1 differ

The same characters, I l 1 and O 0 o, in four fonts at the same size. In Roboto and in Inter, without settings, capital I and lowercase l are almost identical. IBM Plex Sans tells them apart out of the box, and Source Sans 3 tells them apart clearly once two of the font's options are switched on.

The distinction matters most in codes: personal numerical codes (CNP), IBANs, company tax codes (CUI), case numbers, vehicle registration numbers, confirmation codes. There, readers cannot guess from context. There is also a case specific to Romania: the Ukrainian letter І looks identical to the Latin I. A serifed I therefore helps in Cyrillic text too.

Roboto default

Source Sans 3 with serifed I and slashed 0

In a code, context does not help. Anyone reading a personal number, an IBAN or a confirmation code has to recognise every single character.

1.2 Tall lowercase letters

At the same font size, some fonts look 20–30% bigger than others. The reason is the height of the lowercase letters (in typography, the "x-height"). An analysis of 1,049 fonts found it ranges from 0.28 to 0.58 of the font size. The font size alone therefore does not say how big the text looks. A larger x-height helps letter recognition.

Source Sans 3

IBM Plex Sans

Inter

The same text at the same font size. The dotted line shows the height of the lowercase letters. Source Sans 3's lowercase letters are almost 13% shorter than Inter's, so the text looks smaller: with Source Sans 3, body text needs at least 18 px.

1.3 Open shapes, wide letters, space between letters

Roboto more closed shapes

Source Sans 3 open shapes

The openings of a, c, e and s. Wider openings make letters easier to recognise at a glance and at small sizes.

1.4 Dyslexia

Studies of the OpenDyslexic and Dyslexie fonts found no gain in speed or accuracy. With Dyslexie, the small advantage disappeared when the spacing was matched: the spacing helped, not the letter shapes. Wider spacing also helped children with dyslexia in other studies.

1.5 Atkinson Hyperlegible and Luciole

Atkinson Hyperlegible was made by the Braille Institute for people with low vision. It tells letters apart very well, but there is no published study of reading speed or accuracy with it.

Luciole was tested with 145 readers, 73 of them with low vision. About half of those with low vision preferred it, but the measured gain was small. Its text fonts are licensed under CC BY 4.0, which is not a font licence.

1.6 Everyone reads differently

A study of 352 adults and 16 fonts found that each person read 35% faster in their fastest font than in their slowest. The fastest font differed from person to person. 73% of participants wrongly thought their preferred font was also their fastest. Legibility researchers therefore recommend font features, not a particular font, and users should be able to choose their font.

1.7 What accessibility rules require

WCAG, the international web accessibility guidelines, does not require any particular font or size. The European standard EN 301 549 follows WCAG.

Success criterion 1.4.12, however, requires pages to stay usable when users increase:

This concerns the font, but mostly the components: buttons with a fixed height are usually the first to break.

1.8 What is proven and what is not

Claim How solid it is
Taller lowercase letters and a suitable size help recognition solid
Wide letters and wider spacing help people with low vision and with dyslexia solid, moderate effect, studies with small groups
Open shapes are read faster at a glance fairly solid
I, l, 1 and O, 0 must be distinct consensus of standards, few direct studies on interfaces
Serif or sans-serif fonts read better on screen no consistent evidence
Special dyslexia fonts help not supported
Atkinson Hyperlegible is measurably more legible no published evidence
One font is best for everyone contradicted

2. What other states use

State or system Font Licence
European Commission (ECL component library) Inter, which replaced Arial open
EU institutions (europa.eu) Arial system font
USA (USWDS) Source Sans (default); Public Sans, optional, no longer maintained open
Norway Source Sans 3 (NAV); Inter, with the tailed l recommended (Designsystemet) open
Finland (Suomi.fi) Source Sans 3 open
Denmark IBM Plex Sans, across government open
Germany (KERN, the federal and state standard) Fira Sans open
Canada Noto Sans for text, Lato for headings open
Italy Titillium Web; "Titillium Pro" is planned, to fix legibility problems open
Republic of Moldova (the design system's code) Onest open
Estonia (TEDI) Roboto open
United Kingdom (GOV.UK) GDS Transport, kept after the 2025 brand refresh gov.uk domains only
France Marianne reserved for state websites
Netherlands; German federal government; NHS Rijksoverheid Sans; BundesSans; Frutiger proprietary or paid
Romania: the SGG visual identity guide Trajan Pro (institution names), Trebuchet MS (everything else) commercial
Romania: ROeID Sora open, but without Cyrillic letters

No state uses Atkinson Hyperlegible as its main font. You can find more about European systems in Design systems in Europe.

3. What the font has to cover in Romania

3.1 The languages

Languages Characters Note
Romanian ă â î ș ț Ș Ț, with a comma below not ş ţ with a cedilla
Hungarian ő ű Ő Ű
German, Czech, Slovak, Polish, Croatian, Serbian in Latin script, Albanian, Italian ß ě ř ů ľ ą ę ł č ć đ š ž ë ç
Turkish and Tatar ğ ı İ and ş with a cedilla here, the cedilla is correct
Romani Latin letters, plus θ and ʒ in the spelling used in schools ʒ is missing from some fonts
Ukrainian, Russian, Rusyn, Bulgarian, Serbian, Macedonian ґ є і ї; the local forms of Bulgarian and Serbian letters in Bulgarian and Serbian, a few letters (б, г, д, п, т) are drawn differently
Greek the Greek alphabet
Armenian, Yiddish (in the Hebrew alphabet) separate alphabets almost never in the same font; a companion font is added

Source Sans 3 with a comma: correct in Romanian

Source Sans 3 with a cedilla: wrong in Romanian, correct in Turkish and Tatar

Romanian ș and ț take a comma below. The cedilla versions are different characters. The font has to have both, and Romanian text has to use the comma versions.

Source Sans 3 every letter

Atkinson Hyperlegible Next no Cyrillic or Greek

Romanian, Hungarian, Ukrainian and Greek in the same font. Atkinson Hyperlegible, one of the fonts presented as highly legible, has no Cyrillic or Greek letters: empty rectangles appear in their place.

3.2 The candidates, checked

I downloaded 22 open-licence font families from the official source, Google Fonts, together with their licences. I added Trebuchet MS, Verdana and Arial for comparison. Then I used a program to check, character by character, what each font contains. The data in the table comes from the font files, not from descriptions.

Font ș ț, ő ű Cyrillic Bulgarian / Serbian forms Greek Armenian / Hebrew I and l, without settings Slashed 0 Lowercase height Equal-width digits
Source Sans 3 yes yes yes / yes yes no / no distinct (tailed l); with one setting, a serifed I too option 0.478 (smallest) yes
IBM Plex Sans yes yes yes / no yes no / companion font distinct (serifed I, tailed l) option 0.516 yes
Inter yes yes no / no yes no / no the same; distinct with one setting option 0.546 with one setting
Noto Sans yes yes no / yes yes companion fonts similar; no tailed l option 0.536 yes
Fira Sans yes yes unconfirmed yes no distinct (tailed l) option 0.527 with one setting
Open Sans yes yes no / yes yes no / yes similar option 0.535 yes
Roboto (the Android phone font) yes yes not checked yes no the same no 0.528 yes
Atkinson Hyperlegible Next yes no — no no distinct default 0.496 yes
Sora (ROeID) yes no — no no similar no 0.534 yes
Lexend, Public Sans, Red Hat Text, Figtree, Titillium Web yes no — no no varies varies — varies
Trebuchet MS (SGG guide), commercial yes yes — yes no distinct (tailed l) no — —
Arial, commercial yes yes — yes no / yes almost the same no 0.519 —

The lowercase height is given as a fraction of the font size. All the candidates have ș and ț with a comma and ş and ţ with a cedilla, as separate letters.

What the table shows:

4. Practical considerations

5. The recommendation: criteria for the right font

A font suited to the Romanian state's services should meet all the criteria below.

# Criterion How to check
1 Easily confused characters are distinct: I, l and 1; O, 0 and o type "Il1 O0o" and a code (a personal number, an IBAN) and compare them at normal text size
2 Writes every language required in Romania correctly: ș and ț with a comma, ő and ű, Cyrillic with the Bulgarian and Serbian forms, Greek; Armenian and Hebrew through a companion font type a test line in each language and look for empty rectangles or letters from another font
3 Tall enough lowercase letters, with body text sized to match compare fonts at the same size; for body text, at least 16–19 px, depending on the font
4 Open shapes, letters wide enough, no very thin weights for text compare a, c, e, s at small sizes
5 Withstands wider spacing set by the user (WCAG 1.4.12) apply the wider spacing to real pages and components
6 Equal-width digits, for tables, amounts and codes line up a column of amounts
7 Open licence, with the right to host it, use it in apps and documents and pass it on to suppliers read the licence (OFL) and check whether it has a reserved name
8 Maintained and used by other administrations check the latest versions and who else uses it
9 Works everywhere: website, phone apps, documents, PDF test in Word, on Windows with an ordinary monitor, on iOS and on Android
10 Tested with people: older people, people with low vision, Hungarian and Ukrainian speakers a short test, on a form with a personal number and an IBAN

The fonts that meet the criteria best:

In both cases, Noto Sans Armenian and Noto Sans Hebrew would cover Armenian and Hebrew. Inter remains a good option if matching the European Commission matters a lot. It would then need a version with distinct I and l from the start, which its licence allows.

My proposal, the Government of Romania Design System (SDGR), requires "open fonts with correct ș and ț" and with the characters of minority languages. I would not choose the font alone: the choice should be made together with the SGG, which is responsible for the Government's visual identity, and checked with people.

6. What I could not confirm

Sources

← All research documents